ALBERT

Description: Ammonia (NH3) emission from agriculture is an environmental threat and a loss of nitrogen for crop production. Mineral fertilizers and manure are significant sources of NH3; therefore, abatement technologies have been introduced to mitigate these emissions. The aim of this study was to demonstrate that low-cost measuring techniques are suitable to assess NH3 emissions in smaller plots, appropriate to test different managements. Two experiments were established to quantify NH3 emissions from urea application in a multi-plot design with radii of 5 (R5) and 20 m (R20). Field was bare soil partially surrounded by shelterbelts. Measurement techniques included passive flux samplers (Leuning), and passive concentration samplers (ALPHA) coupled to WindTrax dispersion model. NH3 emission from R5 was consistent with the emission from R20 when the surface-to-atmosphere exchange was not affected by shelterbelts, and wind speed near surface was greater than 1 m s−1. Both measurement methods gave unreliable NH3 quantification in combination with wind speed lower than 1 m s−1 and low emission strength. Cumulative emission over 60 h was 2% of the supplied N from the plots not affected by the shelterbelt, and 1% from the plots affected by shelterbelts, indicating that these structures can significantly reduce NH3 emissions.

Description: To achieve superior rice-grain quality, more emphasis has been placed on the genetic diversity of breeding programs, although this improvement could be seriously restricted in the absence of comparable agricultural management practices. Nitrogen (N) application and planting density are two important agronomic practices influencing rice growth, yield, and grain quality. This study investigated the four main aspects of rice-grain quality, namely, milling (brown-rice, milled-rice, and head-rice percentage), appearance (length/width ratio, chalky-kernel percentage, and chalkiness), nutrition (protein content), and cooking and eating quality (apparent amylose content, gel consistency, and pasting viscosities) of two rice cultivars (Shendao 47 and Jingyou 586) under four N rates (0, 140, 180, and 220 kg ha−1), and three planting densities (25 × 104, 16.7 × 104, and 12.5 × 104 hills ha−1) in a field trial from 2015 to 2016. The four main aspects of rice-grain quality were significantly influenced by cultivar. Several aspects were affected by the interactions of N rate and cultivar. No significant interaction between N rate and plating density was detected for all grain-quality parameters. A higher N rate increased the percentages of brown rice and head rice, chalky-kernel percentage, and setback and peak time values, but reduced the length/width ratio, chalkiness, apparent amylose content, gel consistency, and peak-, trough-, and final-viscosity values. These results indicate that the N rate has a beneficial effect on milling and nutritional quality, but a detrimental effect on appearance and cooking and eating quality. Jingyou 586 and Shendao 47 had different responses to planting density in terms of grain quality. Our study indicates that low planting density for Jingyou 586, but a medium one for Shendao 47, is favorable for grain quality.

Description: Plant roots play a significant role in plant growth by exploiting soil resources via the uptake of water and nutrients. Root traits such as fine root diameter, specific root length, specific root area, root angle, and root length density are considered useful traits for improving plant productivity under drought conditions. Therefore, understanding interactions between roots and their surrounding soil environment is important, which can be improved through root phenotyping. With the advancement in technologies, many tools have been developed for root phenotyping. Canopy temperature depression (CTD) has been considered a good technique for field phenotyping of crops under drought and is used to estimate crop yield as well as root traits in relation to drought tolerance. Both laboratory and field-based methods for phenotyping root traits have been developed including soil sampling, mini-rhizotron, rhizotrons, thermography and non-soil techniques. Recently, a non-invasive approach of X-ray computed tomography (CT) has provided a break-through to study the root architecture in three dimensions (3-D). This review summarizes methods for root phenotyping. On the basis of this review, it can be concluded that root traits are useful characters to be included in future breeding programs and for selecting better cultivars to increase crop yield under water-limited environments.

Description: Knowledge about seasonal and litter bag soil position effects on litter decomposition (k value), mineralization and nitrification rate of annual legumes in Puerto Rico is limited. This study determined dry matter yield (DMY), k value of litter bags placed below and above the soil surface, mineralization and nitrification rates of Lablab purpureus cv. “Rongai” and Mucuna pruriens (Velvet bean) seeded in the wet and dry season in Oxisol soils (Typic Eustrustox). There was an interaction (p 〈 0.05) for season and legumes on DMY, k value and N content. “Rongai” DMY was higher for the dry than wet season while Velvet bean had an opposite seasonal response. Higher k value occurred in the wet season for legumes, but “Rongai” had higher k than Velvet bean. For both legumes, N content was higher on litter bag placed below-ground in both seasons. However, in the wet season, there was less N in the above ground litter position. Higher inorganic N was observed at 90 days of soil incubation (DOI) suggesting that N was not available prior to 42 DOI. Nitrification rate was higher for “Rongai” at 22 DOI and lower at 42 and 90 DOI for both legumes. Both legumes enhanced inorganic N, but, regardless of season, Rongai supplied nutrients to the soil faster than Velvet bean. “Rongai” because of its higher k value than Velvet bean is recommended for fast growing row or vegetable crops in Puerto Rico.

Description: Drought stress is one of the most adverse environmental limiting factors for wheat (Triticum aestivum L.) productivity worldwide. For better understanding of the molecular mechanism of wheat in response to drought, a comparative transcriptome approach was applied to investigate the gene expression change of two wheat cultivars, Jimai No. 47 (drought-tolerant) and Yanzhan No. 4110 (drought-sensitive) in the field under irrigated and drought-stressed conditions. A total of 3754 and 2325 differential expressed genes (DEGs) were found in Jimai No. 47 and Yanzhan No. 4110, respectively, of which 377 genes were overlapped, which could be considered to be the potential drought-responsive genes. GO (Gene Ontology) analysis showed that these DEGs of tolerant genotype were significantly enriched in signaling transduction and MAP (mitogen-activated protein) kinase activity, while that of sensitive genotype was involved in photosynthesis, membrane protein complex, and guard cell differentiation. Furthermore, 32 and 2 RNA editing sites were identified in drought-tolerant and sensitive genotypes under drought compared to irrigation, demonstrating that RNA editing also plays an important role in response to drought in wheat. This study investigated the gene expression pattern and RNA editing sites of two wheat cultivars with contrasting tolerance in field condition, which will contribute to a better understanding of the molecular mechanism of drought tolerance in wheat and beyond.

Description: Galactinol synthases (GolSs) are the key enzymes that participate in raffinose family oligosaccharides (RFO) biosynthesis, which perform a big role in modulating plant growth and response to biotic or abiotic stresses. To date, no systematic study of this gene family has been conducted in cassava (Manihot esculenta Crantz). Here, eight MeGolS genes are isolated from the cassava genome. Based on phylogenetic background, the MeGolSs are clustered into four groups. Through predicting the cis-elements in their promoters, it was discovered that all MeGolS members act as hormone-, stress-, and tissue-specific related elements to different degrees. MeGolS genes exhibit incongruous expression patterns in various tissues, indicating that different MeGolS proteins might have diverse functions. MeGolS1 and MeGolS3–6 are highly expressed in leaves and midveins. MeGolS3–6 are highly expressed in fibrous roots. Quantitative real-time Polymerase Chain Reaction (qRT-PCR) analysis indicates that several MeGolSs, including MeGolS1, 2, 5, 6, and 7, are induced by abiotic stresses. microRNA prediction analysis indicates that several abiotic stress-related miRNAs target the MeGolS genes, such as mes-miR156, 159, and 169, which also respond to abiotic stresses. The current study is the first systematic research of GolS genes in cassava, and the results of this study provide a basis for further exploration the functional mechanism of GolS genes in cassava.

Description: Increasing plant density seems to improve the productivity of maize crops, and the understanding of how the metabolism of non-structural carbohydrates is affected in plants under high crop density is critical. Thus, with the objective of further clarifying this issue, maize plants were subjected to densities from 30,000 to 90,000 plants ha−1, and the plant growth, soluble sugars and starch contents, invertase and sucrose synthase activities, and plant production were evaluated. We found that the stalk is more sensitive to the increasing plant density than leaves and kernels. The dry weight of the stalk and leaves per single plant decreased more drastically from low to intermediate plant densities, while grain production was reduced linearly in all plant density ranges, leading to higher values of harvest index in intermediate plant densities. The sucrose concentration did not change in leaves, stalk, or kernels of plants subjected to increasing plant densities at the R4 stage. Also, the specific activity of soluble invertase, bound invertase, and sucrose synthase did not change in leaf, stalk, or kernels of plants subjected to increased plant density. The productivity was increased with the increase in plant density, using narrow row (0.45 m) spacing.

Description: Monocropping systems, which currently dominate China’s major grain production regions, contribute to resource scarcity and environmental pollution. Intercropping has the potential to improve resource use efficiency. However, prior studies of intercropping systems have generally focused on ecological, economic, and social consequences. Here, we make a comparative ecological sustainability analysis on energy capture and efficiency of maize monocropping and maize–soybean intercropping systems through emergy evaluation based on field experiments performed from 2012 to 2014. We find that maize monocropping shows higher sustainability than maize–soybean intercropping in the North China Plain at present. Quantitative results indicate that for maize monocropping, the emergy yield ratio (EYR) and emergy sustainability index (ESI) are 13.7% and 21.1% higher than that of intercropping systems, and the environmental loading ratio (ELR) is 7.3% lower than that of intercropping systems. To further test, we applied three levels of nitrogen fertilizer in intercropping systems (120 kg ha−1, 180 kg ha−1, 240 kg ha−1), and find that a reduced rate of N fertilizer for intercropped system leads to higher sustainability (ESI 5.3% higher) but still lower sustainability than maize monocropping. Key drivers of the different sustainability outcomes are decreased energy output and a larger proportion of labor input associated with intercropping systems.

Description: In the present study, the following was investigated: (a) The effect of ulvan on in vivo and in vitro biocontrol of Debaryomyces hansenii and Stenotrophomonas rhizophila against Fusarium proliferaum and (b) the effect of ulvan on in vivo and in vitro growth of D. hansenii and S. rhizophila and muskmelon quality parameters. The results showed that the biocontrol activity of D. hansenii and S. rhizophila could be enhanced by ulvan (5 g/L). The combination of ulvan and S. rhizophila resulted in a more effective control of fruit rot in comparison to fungicide benomyl. On in vitro growth of F. proliferatum, individual treatments of D. hansenii and S. rhizophila inhibited spore germination and mycelial growth with no statistical difference with the combined treatments. Ulvan does not have a direct effect on the in vivo and in vitro growth of D. hansenii and S. rhizophila. Furthermore, the combined treatments improve the natural disease incidence and quality parameters like weight, firmness, total soluble solids (TSS), and pH. These results suggest that the use of ulvan may be an effective method to improve the biological activity of D. hansenii and S. rhizophila.

Description: The objective of this research was to evaluate the production and phytochemical quality of cucumber (Cucumis sativus) fruits, in response to the foliar application of different seaweed extracts. This study was carried out under shadow mesh conditions in the autumn–winter agricultural cycle at the Instituto Tecnológico de Torreón, Torreón, Coahuila, Mexico. The experimental design was completely random, using six treatments with six repetitions each. The treatments evaluated were: Macrocystis pyrifera, Bryothamnion triquetrum, Ascophyllum nodosum, Grammatophora spp., Macrocystis integrifolia, and a control treatment with inorganic fertilization. The substrate used was a mixture of sand and vermicompost. The yield, commercial size, and phytochemical compounds of the fruit were evaluated. Results showed that the yield using Steiner solution (6.75 kg m−2) was higher than that obtained with Bryothamnion triquetrum algae (6.07 kg m−2). Regarding the phenolic content, the extracts surpassed the control treatment, with Macrocystis pyrifera and Macrocystis integrifolia being statistically equal, with values of 47.37 and 43.73 mg equiv. of Ac. Gallic 100 g fresh weight, respectively. The antioxidant capacity by ABTS+ and DPPH+ methods was higher using the treatment with Macrocystis pyrifera algae with 149.4 and 454.1 μM equiv Trolox/100 g fresh base, respectively. This treatment also presented the highest value of vitamin C with 5.07 mg/100 g fresh base, being 27% greater than the control treatment. Algae extracts increased the quality of the fruits by obtaining the highest antioxidant capacity, making their use a viable option to minimize the application of conventional fertilizers, thereby attenuating the effects on the environment and improving the health of the population.

Description: Agricultural productivity depends on increasingly extreme weather phenomena, and the use of germplasm that has to be continuously improved by plant breeders to become tolerant to various biotic and abiotic stresses. Molecular plant biologists try to understand the mechanisms associated with stress responses and provide knowledge that could be used in breeding programs. To provide a partial overview about our current understanding about molecular and physiological stress responses, and how this knowledge can be used in agriculture, we have edited a special issue on “Biotic and Abiotic Stress Responses in Crop Plants”. Contributions are from different fields including heat stress responses, stress responses during drought and salinity, as well as during flooding, and resistance and susceptibility to pathogenetic stresses and about the role of plant functional metabolites in biotic stress responses. Future research demand in particular areas of crop stress physiology is discussed, as well as the importance of translational research and investigations directly in elite crop plants and in the genetic resources available for breeding.

Description: Work-related musculoskeletal disorders (MSDs) accounted for 32% of days-away-from-work cases in private industry in 2016. Several factors have been associated with MSDs, such as repetitive motion, excessive force, awkward and/or sustained postures, and prolonged sitting and standing, all of which are required in farm workers’ labor. While numerous epidemiological studies on the prevention of MSDs in agriculture have been conducted, an ergonomics evaluation of blueberry harvesting has not yet been systematically performed. The purpose of this study was to investigate the risk factors of MSDs for several types of blueberry harvesting (hand harvesting, semi-mechanical harvesting with hand-held shakers, and over-the-row machines) in terms of workers’ postural loads and self-reported discomfort using ergonomics intervention techniques. Five field studies in the western region of the United States between 2017 and 2018 were conducted using the Borg CR10 scale, electromyography (EMG), Rapid Upper Limb Assessment (RULA), the Cumulative Trauma Disorders (CTD) index, and the NIOSH (National Institute for Occupational Safety and Health) lifting equation. In evaluating the workloads of picking and moving blueberries by hand, semi-mechanical harvesting with hand-held shakers, and completely mechanized harvesting, only EMG and the NIOSH lifting equation were used, as labor for this system is limited to loading empty lugs and unloading full lugs. Based on the results, we conclude that working on the fully mechanized harvester would be the best approach to minimizing worker loading and fatigue. This is because the total component ratio of postures in hand harvesting with a RULA score equal to or greater than 5 was 69%, indicating that more than half of the postures were high risk for shoulder pain. For the semi-mechanical harvesting, the biggest problem with the shakers is the vibration, which can cause fatigue and various risks to workers, especially in the upper limbs. However, it would be challenging for small- and medium-sized blueberry farms to purchase automated harvesters due to their high cost. Thus, collaborative efforts among health and safety professionals, engineers, social scientists, and ergonomists are needed to provide effective ergonomic interventions.

Description: The AGL15 subfamily MADS-box proteins play vital roles in various developmental processes, such as floral transition, somatic embryogenesis, and leaf and fruit development. In this work, an AtAGL15 ortholog, CsMADS26, was cloned from cucumber (Cucumis sativus L.). The open reading frame (ORF) of CsMADS26 is 669 bp in length, encoding a predicted protein of 222 amino acids. The CsMADS26 protein contains a highly conserved MADS-box domain and a variable C domain, as well as less conserved I and K domains. Phylogenetic relationship analysis revealed that CsMADS26 was clustered into the AGL15 clade of AGL15 subfamily. Expression analysis based on qRT-PCR showed that CsMADS26 is mainly expressed in reproductive organs including flowers and fruits. Transgenic Arabidopsis plants with ectopic expression of CsMADS26 exhibited curled rosette and cauline leaves, and the leaf size was much smaller than that of wild-type (WT) plants. These results provide clues for the functional characterization of CsMADS26 in the future.

Description: Rice seedling segmentation is a fundamental process of extracting the guidance line for automated rice transplanters with a visual navigation system, which can provide crop row information to ensure the transplanter plants seedlings along the crop row without damaging seedlings. However, obtaining accurate rice seedling segmentation in paddy fields is still a challenging task. In this paper, a rice seedling segmentation method in paddy fields is proposed. The method mainly consists of two steps: image graying and threshold segmentation. In the procedure of image graying, the RGB (Red Green Blue) seedling image is first converted into the YCrCb color space and a Cg component is constructed. A color-index 2Cg-Cb-Cr is then constructed for image graying based on the excess green index (2G-R-B), which can reduce the influence of illumination variation on the equality of image graying. For the second step, an improved Otsu method is proposed to segment rice seedlings. With respect to the improved Otsu method in this research, the background variance of within class variance is weighted by a probability parameter to ensure that the method works well for both bimodal and near-unimodal histogram images, and the search range of gray levels is constrained to reduce the time to search the segmentation threshold. Experimental results indicate that the proposed method achieves better segmentation results and reduces the computational cost compared with the traditional Otsu method and other improved Otsu methods.

Description: Efficient use of nitrogen (N) fertilizer is critically important for China’s food security and sustainable development. Crop models have been widely used to analyze yield variability, assist in N prescriptions, and determine optimum N rates. The objectives of this study were to use the CERES-Rice model to simulate the N response of different high-latitude, adapted flooded rice varieties to different types of weather seasons, and to explore different optimum rice N management strategies with the combinations of rice varieties and types of weather seasons. Field experiments conducted for five N rates and three varieties in Northeast China during 2011–2016 were used to calibrate and evaluate the CERES-Rice model. Historical weather data (1960–2014) were classified into three weather types (cool/normal/warm) based on cumulative growing degree days during the normal growing season for rice. After calibrating the CERES-Rice model for three varieties and five N rates, the model gave good simulations for evaluation seasons for top weight (R2 ≥ 0.96), leaf area index (R2 ≥ 0.64), yield (R2 ≥ 0.71), and plant N uptake (R2 ≥ 0.83). The simulated optimum N rates for the combinations of varieties and weather types ranged from 91 to 119 kg N ha−1 over 55 seasons of weather data and were in agreement with the reported values of the region. Five different N management strategies were evaluated based on farmer practice, regional optimum N rates, and optimum N rates simulated for different combinations of varieties and weather season types over 20 seasons of weather data. The simulated optimum N rate, marginal net return, and N partial factor productivity were sensitive to both variety and type of weather year. Based on the simulations, climate warming would favor the selection of the 12-leaf variety, Longjing 21, which would produce higher yield and marginal returns than the 11-leaf varieties under all the management strategies evaluated. The 12-leaf variety with a longer growing season and higher yield potential would require higher N rates than the 11-leaf varieties. In summary, under warm weather conditions, all the rice varieties would produce higher yield, and thus require higher rates of N fertilizers. Based on simulation results using the past 20 years of weather data, variety-specific N management was a practical strategy to improve N management and N partial factor productivity compared with farmer practice and regional optimum N management in the study region. The CERES-Rice crop growth model can be a useful tool to help farmers select suitable precision N management strategies to improve N-use efficiency and economic returns.

Description: A better understanding of the capacity of soils to supply nitrogen (N) to wheat can enhance fertilizer recommendations. The aim of this study was to assess the soil mineral N (Nmin) dynamics throughout the wheat growing season in crucial stages for the plant yield and grain protein content (GPC). To this aim, we evaluated the utility of different soil properties analyzed before sowing: (i) commonly used soil physicochemical properties, (ii) potentially mineralizable N or No (aerobic incubation), and (iii) different extraction methods for estimating No. A greenhouse experiment was established using samples from 16 field soils from northern Spain. Wheat N uptake and soil Nmin concentrations were determined at following growing stages (GS): sowing, GS30, GS37, GS60, harvest, post-harvest, and pre-sowing. Pearson’s correlation analysis of the soil properties, aerobic incubations and chemical extractions with the soil Nmin dynamics and N uptake, yield and GPC was performed. In addition, correlations were performed between Nmin and the N uptake, yield, and GPC. The dynamics of soil Nmin throughout the cropping season were variable, and thus, the crop N necessities were variable. The soil Nmin values in the early wheat growth stages were well correlated with the yield, and in the late stages, they were well correlated with GPC. N0 was correlated with the late N uptake and GPC. However, the chemical methods that avoid the long periods required for N0 determinations were not correlated with the N uptake in the late wheat growth stages or GPC. Conversely, clay was positively correlated with the late Nmin values and GPC. Chemical methods were unable to estimate the available soil N in the later stages of the growing cycle. Consequently, as incubation methods are too laborious for their widespread use, further research must be conducted.

Description: Maize grain yield is considered to be highly associated with ear and leaf carbohydrate dynamics during the critical period bracketing silking and during the fast grain filling phase. However, a full understanding of how differences in N availability/plant N status influence carbohydrate dynamics and processes underlying yield formation remains elusive. Two field experiments were conducted to examine maize ear development, grain yield and the dynamics of carbohydrates in maize ear leaves and developing ears in response to differences in N availability. Increasing N availability stimulated ear growth during the critical two weeks bracketing silking and during the fast grain-filling phase, consequently resulting in greater maize grain yield. In ear leaves, sucrose and starch concentrations exhibited an obvious diurnal pattern at both silking and 20 days after silking, and N fertilization led to more carbon flux to sucrose biosynthesis than to starch accumulation. The elevated transcript abundance of key genes involved in starch biosynthesis and maltose export, as well as the sugar transporters (SWEETs) important for phloem loading, indicated greater starch turnover and sucrose export from leaves under N-fertilized conditions. In developing ears, N fertilization likely enhanced the cleavage of sucrose to glucose and fructose in the cob prior to and at silking and the synthesis from glucose and fructose to sucrose in the kernels after silking, and thus increasing kernel setting and filling. At the end, we propose a source-sink carbon partitioning framework to illustrates how N application influences carbon assimilation in leaves, transport, and conversions in developing reproductive tissues, ultimately leading to greater yield.

Description: Individual sugars were analyzed by High Performance Liquid Chromatography (HPLC) in plum juice samples obtained from “Stanley”, “Vânăt de Italia”, and “Tuleu Gras”. The samples were harvested from the inside and periphery of the crown during six development phases. The aim of the present study was to determine the individual sugars in plum juice by the HPLC and Fourier transform mid-infrared spectroscopy (FT-MIR) methods and to validate them. Our findings were as follows: levels between 0.26–3.73% for fructose, 1.43–1.10% for glucose, and 0.01–10.19% for sucrose. The FT-MIR analyses confirmed the differences between the juice samples, mainly in the spectral region characteristic to sugars which ranged from 900 to 1500 cm−1. FT-MIR coupled with Partial least squares (PLS) was used to develop calibration models for estimating individual plum juice sugars, the predictive characteristics being assessed. The optimal regions and spectral pretreatments were 800–1600 cm−1 and Savitzky Golay first derivative (d1) for fructose, 800–1600 cm−1 for glucose, and 915–1145 cm−1 and second derivative (d2) for sucrose. The selection of optimal spectral zones and pre-treatments led to PLS calibration models with acceptable predictive abilities for glucose, very good for sucrose, and less satisfactory for fructose. Moreover, the FT-MIR results were compared to the HPLC results in external validation tests and reference values included.

Description: Under a global warming scenario, it is important to adopt practices that favor soil water conservation, such as plant intercropping systems and the use of plastic mulching. The objective of this study was to determine how microenvironment, morphology, productivity and quality of jalapeño peppers were affected by corn intercropping and the use of plastic mulching. Two experiments were conducted during 2015 and 2016 in the Valley of Mexicali, Mexico, a region characterized by its extreme aridity, soil salinity, hot temperatures and high radiation during the summer. Four treatments were tested: jalapeño peppers grown on bare soil (BS); on bare soil intercropped with corn (BS+IC); on plastic mulch (PMu); and on plastic mulch intercropped with corn (PMu+IC). The response variables measured were yield, fruit quality attributes, microclimatic variables, and morphology of the pepper crop. PMu treatment produced the tallest pepper plants and yields, while the BS+IC treatment produced the smallest plants and the lowest yields. A possible explanation for the higher biomass and crop yield of the PMu treatment is the lack of competition from corn and the effect of plastic mulching in reducing soil salinity. It is concluded that competition from corn on jalapeño pepper dramatically affected the pepper’s productivity, particularly under high soil salinity and extremely high temperature conditions.

Description: Understanding spatial and temporal variability patterns of crop yield and their relationship with soil properties can provide decision support to optimize crop management. The objectives of this study were to (1) determine the spatial and temporal variability of cotton (Gossypium hirsutum L.) lint yield over different growing seasons; (2) evaluate the relationship between spatial and temporal yield patterns and apparent soil electrical conductivity (ECa). This study was conducted in eight production fields, six with 50 ha and two with 25 ha, on the Southern High Plains (SHP) from 2000 to 2003. Cotton yield and ECa data were collected using a yield monitor and an ECa mapping system, respectively. The amount and pattern of spatial and temporal yield variability varied with the field. Fields with high variability in ECa exhibited a stronger association between spatial and temporal yield patterns and ECa, indicating that soil properties related to ECa were major factors influencing yield variability. The application of ECa for site-specific management is limited to fields with high spatial variability and with a strong association between yield spatial and temporal patterns and ECa variation patterns. For fields with low variability in yield, spatial and temporal yield patterns might be more influenced by weather or other factors in different growing seasons. Fields with high spatial variability and a clear temporal stability pattern have great potential for long-term site-specific management of crop inputs. For unstable yield, however, long-term management practices are difficult to implement. For these fields with unstable yield patterns, within season site-specific management can be a better choice. Variable rate application of water, plant growth regulators, nitrogen, harvest aids may be implemented based on the spatial variability of crop growth conditions at specific times.

Description: Development of high yielding and more palatable glutinous rice is an important goal in breeding and long-standing cultural interaction in Asia. In this study, the TGW6 and Wx, major genes conferring 1000 grain weight (GW) and amylose content (AC), were edited in a maintainer line by CRISPR/Cas9 technology. Four targets were assembled in pYLCRISPR/Cas9Pubi-H vector and T0 mutant plants were obtained through Agrobacterium mediated transformation with 90% mutation frequency having 28% homozygous mutations without off-target effects in three most likely sites of each target and expression level of target genes in mutant lines was significantly decreased (P 〈 0.01), the GW and gel consistency (GC) were increased, and the AC and gelatinization temperature (GT) were decreased significantly and grain appearance was opaque, while there was no change in starch content (SC) and other agronomic traits. Mutations were inheritable and some T1 plants were re-edited but T2 generation was completely stable. The pollen fertility status was randomly distributed, and the mutant maintainer lines were hybridized with Cytoplasmic Male Sterile (CMS) line 209A and after subsequent backcrossing the two glutinous CMS lines were obtained in BC2F1. The identified proteins from anthers of CMS and maintainer line were closely associated with transcription, metabolism, signal transduction, and protein biosynthesis. Putative mitochondrial NAD+-dependent malic enzyme was absent in CMS line which caused the pollen sterility because of insufficient energy, while upregulation of putative acetyl-CoA synthetase and Isoamylase in both lines might have strong relationship with CMS and amylose content. High yielding glutinous CMS lines will facilitate hybrid rice breeding and investigations of proteins linked to male sterility will provide the insights to complicated metabolic network in anther development.

Description: Drought and low phosphorus (P) availability are major limitations for rainfed rice production. Crop roots are important for soil resource acquisition and tolerance to P and water limitations. Two pot and two field trials were conducted to evaluate architectural root responses of contrasting rice varieties to combinations of different levels of P (deficient to non-limiting) and water availability (water stressed to submergence) and to identify the interactions with different varieties. Root development was then related to drought and/or low P tolerance. Although shoot and root growth responded more to P than to water availability, architectural root responses to water were much more prominent than responses to P availability. Reduced water availability decreased nodal thickness and increased secondary root branching, both factors partially enhancing P uptake efficiency and even overcoming a decreased root:shoot ratio under reduced water availability. In contrast to root thickness and secondary branching, basal lateral root density was strongly determined by variety and was related to enhanced P uptake. Reduced water availability induces root modifications which—apart from enhancing drought resilience—also affect P uptake efficiency. Future research on rice roots and nutrient uptake may hence take into account the large effects of water on root development.

Description: Subsoil tillage loosens compacted soil for better plant growth, but promotes water loss, which is a concern in areas that are commonly irrigated. Therefore, our objective was to determine the physiological responses of high yield spring maize (Zea mays L.) to subsoil tillage depth when grown in the Western plain irrigation area of Inner Mongolia, China. Our experiment during 2014 and 2015 used Zhengdan958 (Hybrid of Zheng58 × Chang7-2, produced by Henan academy of agricultural sciences of China, with the characteristics of tight plant type and high yield) and Xianyu335 (Hybrid of PH6WC × PH4CV, produced by Pioneer Corp of USA, with the characteristic of high yield and suitable of machine-harvesting) with three differing subsoil tillage depths (30, 40, or 50 cm) as the trial factor and shallow rotary tillage as a control. The results indicated that subsoil tillage increased shoot dry matter accumulation, leading to a greater shoot/root ratio. Subsoil tillage helped retain a greater leaf area index in each growth stage, increased the leaf area duration, net assimilation rate, and relative growth rate, and effectively delayed the aging of the blade. On average, compared with shallow rotary, the grain yields and water use efficiency increased by 0.7–8.9% and 1.93–18.49% in subsoil tillage treatment, respectively, resulting in the net income being increased by 2.24% to 6.97%. Additionally, the grain yield, water use efficiency, and net income were the highest under the treatment of a subsoil tillage depth of 50 cm. The results provided a theoretical basis for determining the suitable chiseling depth for high-yielding spring corn in the Western irrigation plains of Inner Mongolia.

Description: Hydraulic redistribution (HR) by plant roots can increase moisture content in the dry, mostly upper, parts of the soil. HR helps maintain the viability of fine roots, root hydraulic conductivity, microbial activity and facilitate nutrient uptake. Plants can supply water to other surrounding plants by HR under drought conditions. In oil sands reclamation areas in Northeastern Alberta, Canada, reconstructed soils commonly suffer from the problems of drought, high pH, salinity, and compaction, which often impact revegetation success. In this study, we investigated the HR potential of two herbaceous plants that are frequently present in oil sands reclamation sites: slender wheatgrass (Elymus trachycaulus Link Malte) and yellow sweet clover (Melilotus officinalis L.), using a vertically split-root growth setup and treatments with deuterium-enriched water. Our objective was to test the potential benefits of HR on drought responses of seedlings of the commonly used plant species for oil sand reclamation, balsam poplar (Populus balsamifera L.), when these plants were grown together under controlled environment conditions. We found that both wheatgrass and yellow sweet clover could redistribute water in the upward and downward directions. However, the amount of water released by the roots was not sufficient to alleviate the effects of drought stress on the associated balsam poplar seedlings. Longer-term field studies should be carried out in order to examine, under different environmental conditions, the potential benefits of HR in these herbaceous plants to the establishment and growth of other plant species that are used for land reclamation.

Description: Cotton is one of the most important economic crops worldwide. As the global demands rising, cotton yield improvement is the most important goal of cotton breeding. Hybrids have great potential for increasing yield, however, the genetic mechanism of hybrids is still not clear. To investigate the genetic basis of cotton hybrids, we resequenced 9053 and sGK9708 with 62.13x coverage depth, the parents of the elite hybrid cotton CCRI63 that has obvious heterosis in lint percentage (LP) and boll weight (BW). Based on the cotton reference genome (TM-1), 1,287,661 single nucleotide polymorphisms (SNPs) and 152,479 insertions/deletions (InDels) were identified in 9053, and 1,482,784 SNPs and 152,985 InDels in sGK9708. Among them, 8649 SNPs and 629 InDels in the gene coding regions showed polymorphism between parents. Moreover, these variations involved 5092 genes, and 3835 of these genes were divided into 10 clusters based on the gene expression profiles. The genes in Cluster 3 and 7 were specifically expressed in the ovule and fiber development stage, suggesting that they might relate to LP and BW. We further co-localized the polymorphic SNPs and InDels with the reported quantitative trait loci (QTLs) of LP and BW, and identified 68 genes containing the polymorphic SNPs or InDels within these QTL intervals and as being related to fiber development. This suggested that the outstanding traits of CCRI63 such as LP and BW might be generated by accumulating the favorable variations from the parents. The results generated herein provide a genetic basis for cotton hybrids and genetic markers for marker-assisted selection breeding of cotton.

Description: Sustainable crop production systems can be attained by using inputs efficiently and nitrogen use efficiency (NUE) parameters are indirect measurements of sustainability of production systems. The objective of this study was to investigate the effect of selected nitrogen (N) management treatments on wheat yields, grain and straw N concentration, and NUE parameters, under conservation agriculture (CA). The present study was conducted at the International Maize and Wheat Improvement Center (CIMMYT), in northwest, Mexico. Seventeen treatments were tested which included urea sources, timing, and methods of fertilizer application. Orthogonal contrasts were used to compare groups of treatments and correlation and regression analyses were used to look at the relationships between wheat yields and NUE parameters. Contrasts run to compare wheat yields or agronomic efficiency of N (AEN) performed similarly. Sources of urea or timing of fertilizer application had a significant effect on yields or AEN (p 〉 0.050). However, methods of application resulted in a highly significant (p 〈 0.0001) difference on wheat yields and agronomic efficiency of N. NUE parameters recorded in this study were average but the productivity associated to NUE levels was high. Results in this study indicate that wheat grew under non-critically limiting N supply levels, suggesting that N mineralization and reduced N losses from the soil under CA contributed to this favorable nutritional condition, thus minimizing the importance of N management practices under stable, mature CA systems.

Description: Olive anthracnose is a very common and severe disease caused by diverse species of fungi belonging to Colletotrichum acutatum and Colletotrichum gloeosporioides complexes. To understand aspects of the Colletotrichum colonization and primary infection in olives, Colletotrichum spp. were isolated from the interior of 2-year stems, flower buds, and immature fruits of three important olive cultivars, Galega vulgar, Cobrançosa, and Azeiteira, from different sites within Alentejo, a major olive-producing region in Portugal. A total of 270 trees was sampled, and 68 Colletotrichum spp. isolates were obtained from 46 olive trees. DNA extraction and amplification of β-tubulin and GADPH genes through PCR revealed that the vast majority of the isolates showed high similarity to Colletotrichum nymphaeae, and only three isolates showed high similarity to Colletotrichum godetiae. The highest number of Colletotrichum spp. isolates was detected in olive trees from Galega vulgar and in immature fruits. No significant differences in the number of Colletotrichum spp. isolates were found in trees from different sites. The highest percentages of infected immature fruits were obtained in trees that also presented a high percentage of 2-year stem infections, which may indicate that 2-year stems serve as important sources of inoculum, and the fungus may travel from the stems to other parts of the plant. Another indication of such possibility is that one isolate of C. nymphaeae (C. nymphaeae 2), characterized by a unique nucleotide mutation within the beta tubulin gene, was present in different organs of the same tree, both in 2-year stems and in recently formed vegetative organs as flower buds and immature fruits, which seem to suggest that it may be the same isolate, which has moved systemically inside the plant. The results presented here can play an important role in working out strategies for the effective and timely management of the disease and in reducing the number of unnecessary fungicide applications.

Description: The tomato commercial groups cherry and fresh market, mainly classified by fruit size, have clearly segregated markets. We aimed to estimate the variation within and between these groups and to analyze factors that impact consumer acceptance. To this end, we studied the chemical profile (dry matter, sugars, acids) and fruit morphology (Tomato Analyzer) of 63 accessions grown in 2 environments (open air/soil culture; greenhouse/soilless culture). To identify traits underlying consumer preferences, we used a trained panel for quantitative descriptive sensory analyses and consumer surveys on a subset of genotypes. Our results confirm the higher content of reducing sugars (fructose, glucose), soluble solids, dry matter, and glutamic acid in the cherry group and the important effects of environment and genotype-by-environment interactions on fruit quality traits. The diversity within cherry for chemical composition is 1.4-fold to 2.1-fold that of fresh market. Differences in fruit morphological traits (weight, shoulder height, height/width relation) were highly related to fruit size, but no differences between groups were found for the internal structure of the fruit (locular relative content). Consumers value sweetness, glutamic acid, titratable acidity, and juiciness in cherry, and sweetness and taste intensity in the fresh market group. The implications for plant breeding are discussed.

Description: Green peach aphid, Myzus persicae (Hemiptera: Aphididae), is an economically important pest of crops within more than 40 plant families all over the world. This study encompasses in-vitro pathogenicity of two strains of Beauveria bassiana (BB-72 and BB-252) and one strain of Lecanicillium lecanii (V-4) against green peach aphid (M. persicae). Using a leaf-dip method, three different bioassays were conducted comprised of filtrates and conidial concentrations of BB-72, BB-252 and V-4 fungal strains and their binary combinations. Infiltrate bioassays, 2 mL fungal filtrate of each strain was used. In conidial bioassays, three different concentrations (i.e., 1 × 106, 1 × 107 and 1 × 108 conidia mL−1) of each fungal strain were used, while in binary combination bioassays, LC50 and LC33 of these fungal strains were evaluated. According to the results, maximum pathogenicity against test aphids was observed at 10th day of all treatments. Both strains of B. bassiana (BB-72 and BB-252) exhibited higher mortality of aphids (up to 95 and 91%, respectively) than L. lecanii (V-4) strain (87%) in all three types of bioassays. Moreover, binary combinations of BB-72 and BB-252 strains showed significantly higher aphid mortality (94%) than other combinations. Reduced mortality in case of fungal combinations of V-4 strain might be due to the antagonistic effect of L. lecanii strain along with both strains of B. bassiana. Nevertheless, evaluation of combined pathogenicity of the fungal strains constitutes the novelty of this in-vitro study which revealed that both strains of B. bassiana (i.e., BB-72 and BB-252) are mutually compatible and can be utilized together as new biocontrol tools against destructive insect pests such as M. persicae.

Description: Peach market is facing a constant decrease due to the poor fruit quality perceived at consumption that might be greatly affected by fruit ripening stage at harvest and by the post-harvest management. The present work aimed at clarifying the influence of maturity at harvest on the evolution of peach aroma and quality during shelf-life after prolonged cold storage. “August Flame” peaches were harvested at three maturity stages, determined based on IAD (index of absorption difference) and ethylene emission. Fruit quality traits (firmness, soluble solids, titratable acidity), ethylene and volatile organic compound (VOC) emission were monitored during for four weeks of cold storage (0 °C). Every week of cold storage was followed by 6 days of shelf-life (18 °C). Ripening segregation at harvest based on IAD was successful since each maturity classes significantly differed based on all quality traits. Cold storage enhanced the aroma development of ‘August Flame’ peach, primarily by increasing the emission of esters and lactones associated with pleasant aroma. Moreover, cold storage also reduced the differences in aroma between the maturity classes. The role of ethylene, which was also influenced by cold storage, in regulating the VOCs emission is discussed.

Description: Temporal and spatial resolution of satellite images are coarse and cannot provide the real-time, meter-scale resolution monitoring required in many applications, such as precision agriculture. Since high resolution thermal infrared data provide one means to observe canopy temperature variance, we developed an algorithm (three-temperature model, 3T) to estimate transpiration rate at meter-scale pixels and detected transpiration variation for soybean under different upper irrigation limits: No irrigation, 35% of field capacity (FC), 55% of FC, and 75% of FC, denoted as W0, W1, W2, and W3, respectively. The spatial patterns of the transpiration rate indicated that heterogeneity is common in farmland. Transpiration rates in the wet treatment (i.e., W3) were consistently higher than that in the dry treatment (i.e., W0). Transpiration rates reached peak values at around 12:30–14:30 and most of values showed that W3 〉 W2 〉 W1 〉 W0, with 0.91 mm/h, 0.89 mm/h, 0.79 mm/h, and 0.62 mm/h during the reproductive period, respectively. In general, the transpiration rate of soybean increased with increasing irrigation quantities. With a higher irrigation total, soil water content increased gradually, and then the transpiration rate increased. Although land surface temperature decreased by only 8.57 K (Kelvin), 6.33 K, and 5.47 K, respectively, the transpiration rate increased by 78%, 60%, and 40%, respectively, for the W3, W2, and W1 treatment compared with the W0 treatment. The magnitude of transpiration change is greater than that of canopy temperature, but both parameters are strongly interrelated with each other through a non-linear correlation. Heterogeneity of canopy leaf temperature and transpiration is mainly due to physical and biological interactions. Understanding transpiration rate and canopy temperature heterogeneity under different irrigation treatments can not only help in scheduling irrigation, but also in enhancing water utilization efficiency in irrigated agriculture. The real-time monitoring of crop transpiration at meter-scale is of great importance for large irrigation systems, especially for precision irrigation, and will have great application prospects in the near future.

Description: Water demand in Korea has triggered the need for fresh water to be used for agriculture. Agricultural drainage water (ADW) is a way of coping with the growing demand for fresh water for agriculture. In this study, a water quality model (WQM), and an algorithm were used in order to determine the water quality and optimize the water reuse quantity in the Osan stream drain, South Korea. The water quality associated with the drain was stimulated using the QUAL2Kw model and the uncertainty analysis and sensitivity analysis with the use of Monte Carlos Simulation was performed to determine the performance of the WQM. Jaya algorithm technology was used as an optimization tool to find optimal ADW reuse quantities at particular withdrawal points. For calibration and validation, the model was applied twice for both summer and winter seasons. The results show that the reuse quantities represent 77.2% and 49.8% of the available ADW in the study area for summer and winter, respectively, representing 49.1% and 54.5% of seasonal canal delivery. The utilization of the simulation-optimization model is usually well suited for decision support leading to near-optimum reuse assortment of ADW for irrigation.

Description: The rice-wheat system (RWS), managed over 10.5 Mha in the Indo-Gangetic Plains of India suffers from production fatigue caused by declining soil organic matter, multi-nutrient deficiencies and diminishing factor productivity. We, therefore, conducted a long-term field experiment (1998–1999 to 2017–2018) in Modipuram, India to study the effect of continuous use of farmyard manure (FYM) as an organic fertilizer (OF), mineral fertilizers applied alone (RDF) and their combination (IPNS), as well as the inclusion of forage berseem (IPNS+B) or forage cowpea (IPNS+C) on crop yield, soil health and profits. The long-term yield trends were positive (p 〈 0.05) in all treatments except the control (unfertilized) in rice, and the control and RDF in wheat. Although the yields of rice, wheat and RWS were highest under IPNS treatments (IPNS, IPNS+B, IPNS+C), the maximum annual yield increase in rice (9.2%) and wheat (13.7%) was obtained under OF. A linear regression fitted to the yield data under different IPNS options revealed a highly significant (p 〈 0.001) annual yield increase in rice (5.1 to 6.6%) and wheat (6.8 to 7.7%) crops. Continuous rice-wheat cropping with RDF brought an increase in soil bulk density (Db) over the initial Db at different soil profile depths, more so at depths of 30–45 cm, but inclusion of forage cowpea or berseem in every third year (IPNS+B or C) helped to decrease Db, not only in surface (0–15 cm) but also in sub-surface (15–30 and 30–45 cm depth) soil. Whereas soil organic carbon (SOC) increased under OF, IPNS and IPNS + legume (B or C) treatments, it remained unaffected under RDF after 20 RW cycles. The inclusion of legumes along with IPNS not only helped to trap the NO3–N from soil layers below 45 cm but also increased its retention in the upper soil (0–15 cm depth). On the other hand, RDF had a higher NO3–N content in the lower layers (beyond 45 cm depth), indicating downward NO3–N leaching beyond the root zone. A build-up of Olsen-P was noticed under RDF at different time intervals. The soil exchangeable K and available S contents were maximal under OF and IPNS options, whereas a decline in DTPA extractable-Zn was recorded under OF. Overall, RWS economics revealed that OF treatment involved the maximum cost of cultivation (US$1174 ha−1) with the least economic net return (US$1211 ha−1). Conversely, IPNS + legume (B or C) had lowest cost of cultivation (US$707 to 765 ha−1) and a significantly higher (p 〈 0.05) net return (US$2233 to 2260 ha−1). The study, thus, underlines the superiority of IPNS over RDF or OF; the inclusion of legumes gives an added advantage in terms of production sustainability and soil health. Further studies involving IPNS ingredients other than FYM is needed to develop location-specific IPNS recommendations.

Description: The impact of nitrogen (N)-limiting conditions after silking on kernel yield (KY)-related traits and whole plant N management was investigated using fifteen maize lines representative of plant genetic diversity in Europe and America. A large level of genetic variability of these traits was observed in the different lines when post-silking fertilization of N was strongly reduced. Under such N-fertilization conditions, four different groups of lines were identified on the basis of KY and kernel N content. Although the pattern of N management, including N uptake and N use was variable in the four groups of lines, a number of them were able to maintain both a high yield and a high kernel N content by increasing shoot N remobilization. No obvious relationship between the genetic background of the lines and their mode of N management was found. When N was limiting after silking, N remobilization appeared to be a good predictive marker for identifying maize lines that were able to maintain a high yield and a high kernel N content irrespective of their female flowering date. The use of N remobilization as a trait to select maize genotypes adapted to low N input is discussed.

Description: Adoption of better management practices is crucial to lessen the impact of anthropogenic disturbances on tallgrass prairie systems that contribute heavily for livestock production in several states of the United States. This article reviews the impacts of different common management practices and disturbances (e.g., fertilization, grazing, burning) and tallgrass prairie restoration on plant growth and development, plant species composition, water and nutrient cycles, and microbial activities in tallgrass prairie. Although nitrogen (N) fertilization increases aboveground productivity of prairie systems, several factors greatly influence the range of stimulation across sites. For example, response to N fertilization was more evident on frequently or annually burnt sites (N limiting) than infrequently burnt and unburnt sites (light limiting). Frequent burning increased density of C4 grasses and decreased plant species richness and diversity, while plant diversity was maximized under infrequent burning and grazing. Grazing increased diversity and richness of native plant species by reducing aboveground biomass of dominant grasses and increasing light availability for other species. Restored prairies showed lower levels of species richness and soil quality compared to native remnants. Infrequent burning, regular grazing, and additional inputs can promote species richness and soil quality in restored prairies. However, this literature review indicated that all prairie systems might not show similar responses to treatments as the response might be influenced by another treatment, timing of treatments, and duration of treatments (i.e., short-term vs. long-term). Thus, it is necessary to examine the long-term responses of tallgrass prairie systems to main and interacting effects of combination of management practices under diverse plant community and climatic conditions for a holistic assessment.

Description: The use of combinations of two or more genes controlling carbohydrate characters of corn is an attractive way to improve table quality of sweet corn. Poor seed quality of the inbred lines hinders the progress of this strategy for hybrid seed production. The objective of this study was to evaluate sweet corn inbred lines with combinations of double and triple recessive genes for germination percentage, seed vigor, total sugar content, and starch content. Eleven sweet corn genotypes including seven inbred lines (F6 generation) with different combinations of genes controlling carbohydrate characters and four F1 hybrids were used. The germination experiment was conducted under standard test between papers (BP) and accelerated aging (AA) test. The data were recorded for germination percentage, germination speed, normal and abnormal seedling, seedling length, and seedling dry weight. The seeds were analyzed for total sugar and starch content in endosperm at maturity stage. The results showed that single recessive genotype (sh2sh2) had high germination percentage and seedling vigor. The combinations of bt or sh2 gene with wx gene resulted in low germination percentage and poor seedling vigor. However, combinations of triple recessive genes (btbt sh2sh2 wxwx) had good germination in BP test but they performed poorly in AA test.

Description: Kernel images of six wheat species were subjected to shape and color analyses to determine variations in the morphometric parameters of grain. The values of kernel shape descriptors (area, perimeter, Feret diameter, minimal Feret diameter, circularity, aspect ratio, roundness, solidity) and color descriptors (H, S, I and L*a*b*) were investigated. The influence of grain colonization by endophytic fungi on the color of the seed coat was also evaluated. Polish wheat grain was characterized by the highest intraspecific variation in shape and color. Bread wheat was most homogeneous in terms of the studied shape and color descriptors. An analysis of variations in wheat lines revealed greater differences in phenotypic traits of relict wheats, which have a larger gene pool. The grain of ancient wheat species was characterized by low roundness values and relatively low solidity. Shape and color descriptors were strongly discriminating components in the studied wheat species. Their discriminatory power was determined mainly by genotype. A method that supports rapid discrimination of cereal species and admixtures of other cereals in grain batches is required to guarantee the quality and safety of grain. The results of this study indicate that digital image analysis can be effectively used for this purpose.

Description: The information on genotypic responses to the seasonal variation in the starch content, starch yield, and starch quality of cassava is limited. The objective of this research was to investigate the seasonal variation of starch characteristics of three cassava genotypes grown under irrigation. The experiment was conducted at four planting dates (20 April, 30 June, 5 October, and 15 December 2015). Three cassava genotypes (CMR38-125-77, Kasetsart 50, and Rayong 11) were evaluated in a randomized complete block design with four replications and the plants were harvested at 12 months. The planting date contributed the largest portion of the total variation in the starch content, starch yield, and starch granule size. The amylose content variability was heavily influenced by genotype. Cassava planted on 5 October or 15 December had greater starch content, starch yield, and starch granule in most genotypes. This was likely due to a higher temperature and solar radiation during the 3–9 months post-planting. CMR38-125-77 showed a consistently high starch content, starch yield, and high amylose content for most planting dates except for the starch yield on 20 April, of which Rayong 11 was the best. These findings will be useful for choosing suitable cassava genotypes for different growing seasons and for facilitating breeding efforts for high starch-yielding and high-quality cassava starch in the future.

Description: This study investigated the impact of organically grown cereals on the level of free asparagine (Asn) with simultaneous consideration of grain yields and flour qualities over three growing seasons in Germany. Additionally, the relation of free Asn and acrylamide (AA) was investigated. By including free Asn results of a second trial site, heritability of the trait free Asn was calculated. Free Asn was significantly influenced by species and within species by cultivars. Rye showed the highest free Asn amount, followed by einkorn, emmer, wheat, and spelt. Replacing rye with spelt would reduce free Asn by 85%. Cultivars differed in free Asn by up to 67% (wheat), 55% (spelt), and 33% (rye). Year significantly influenced free Asn levels. Heritability was high for wheat and spelt concerning locations, but regarding years, heritability was low for wheat but high for spelt and rye. For organically grown cereals, the relation between free Asn and AA formation has never been investigated. Across species and years, a correlation of R2 = 0.69 *** was found. Thus, free Asn can serve as an indicator for AA formation. In conclusion, the level of free Asn can be highly influenced by proper selection of species and cultivars.

Description: A field experiment was conducted in Ninghe, Tianjin, China, using the 15N isotope method to determine the fate of N sources, application effect of organic fertilizer on the growth of rice plant organs, N uptake by rice, and N use efficiency. The experiment included eight treatments: CK-N (control + no-duck), CK-D (control + ducks), CF-N (chemical fertilizer + no-ducks), CF-D (chemical fertilizer + ducks), CM-N (chemical fertilizer + organic fertilizer + no-ducks), CM-D (chemical fertilizer + organic fertilizer + ducks), CD-N (chemical fertilizer 30% off + organic fertilizer + no-ducks), and CD-D (chemical fertilizer 30% off + organic fertilizer + ducks). The results showed that the application of organic fertilizer whether CM or CD in grain and leaf significantly increased N concentration; leaf and root P concentrations over control (CK) and chemical fertilizer (CF). In contrast, straw and root N concentrations, including grain and straw P concentrations did not show any difference between duck and no-duck treatment. Moreover, non-significant differences were found in 15N fresh grain and husk concentration. Both organs ranged from 14.2–14.4 g·kg−1 and 6.2–6.3 g·kg−1, respectively. Likewise, N uptake and N use efficiency in fresh grain and husk were not significantly differed within duck and without duck treatment. However, N uptake in fresh grain and husk ranged at the rates of 54.90–93.69 and 6.43–11.04 kg ha−1 with duck and without duck treatment. N use efficiency in fresh grain and husk ranged from 21.55%–34.61% and 2.61%–4.24%, respectively. Overall organic fertilizer has a significant influence on rice growth and promotes crop productivity.

Description: This study sought to verify whether remote sensing offers the ability to efficiently delineate olive tree canopies using QuickBird (QB) satellite imagery. This paper compares four classification algorithms performed in pixel- and object-based analyses. To increase the spectral and spatial resolution of the standard QB image, three different pansharpened images were obtained based on variations in the weight of the red and near infrared bands. The results showed slight differences between classifiers. Maximum Likelihood algorithm yielded the highest results in pixel-based classifications with an average overall accuracy (OA) of 94.2%. In object-based analyses, Maximum Likelihood and Decision Tree classifiers offered the highest precisions with average OA of 95.3% and 96.6%, respectively. Between pixel- and object-based analyses no clear difference was observed, showing an increase of average OA values of approximately 1% for all classifiers except Decision Tree, which improved up to 4.5%. The alteration of the weight of different bands in the pansharpen process exhibited satisfactory results with a general performance improvement of up to 9% and 11% in pixel- and object-based analyses, respectively. Thus, object-based analyses with the DT algorithm and the pansharpened imagery with the near-infrared band altered would be highly recommended to obtain accurate maps for site-specific management.

Description: Agronomy, Vol. 8, Pages 129: Automatic Segmentation and Counting of Aphid Nymphs on Leaves Using Convolutional Neural Networks Agronomy doi: 10.3390/agronomy8080129 Authors: Jian Chen Yangyang Fan Tao Wang Chu Zhang Zhengjun Qiu Yong He The presence of pests is one of the main problems in crop production, and obtaining reliable statistics of pest infestation is essential for pest management. Detection of pests should be automated because human monitoring of pests is time-consuming and error-prone. Aphids are among the most destructive pests in greenhouses and they reproduce quickly. Automatic detection of aphid nymphs on leaves (especially on the lower surface) using image analysis is a challenging problem due to color similarity and complicated background. In this study, we propose a method for segmentation and counting of aphid nymphs on leaves using convolutional neural networks. Digital images of pakchoi leaves at different aphid infestation stages were obtained, and corresponding pixel-level binary mask annotated. In the test, segmentation results by the proposed method achieved high overlap with annotation by human experts (Dice coefficient of 0.8207). Automatic counting based on segmentation showed high precision (0.9563) and recall (0.9650). The correlation between aphid nymph count by the proposed method and manual counting was high (R2 = 0.99). The proposed method is generic and can be applied for other species of pests.

Description: Agronomy, Vol. 8, Pages 131: Halotolerant Bacterial Diversity Associated with Suaeda fruticosa (L.) Forssk. Improved Growth of Maize under Salinity Stress Agronomy doi: 10.3390/agronomy8080131 Authors: Faiza Aslam Basharat Ali Halotolerant bacterial strains associated with the rhizosphere and phytoplane of Suaeda fruticosa (L.) Forssk. growing in saline habitats were isolated to mitigate the salinity stress of Zea mays L. 16S rRNA gene sequencing confirmed the presence of strains that belong to Gracilibacillus, Staphylococcus, Virgibacillus, Salinicoccus, Bacillus, Zhihengliuella, Brevibacterium, Oceanobacillus, Exiguobacterium, Pseudomonas, Arthrobacter, and Halomonas genera. Strains were screened for auxin production, 1-aminocyclopropane-1-carboxylate (ACC)-deaminase, and biofilm formation. Bacterial auxin production ranged from 14 to 215 µg mL−1. Moreover, several bacterial isolates were also recorded as positive for ACC-deaminase activity, phosphate solubilization, and biofilm formation. In pot trials, bacterial strains significantly mitigated the salinity stress of Z. mays seedlings. For instance, at 200 and 400 mM NaCl, a significant increase of shoot and root length (up to onefold) was recorded for Staphylococcus jettensis F-11. At 200 mM, Zhihengliuella flava F-9 (45%) and Bacillus megaterium F-58 (42%) exhibited significant improvements for fresh weight. For dry weight, S. jettensis F-11 and S. arlettae F-71 recorded up to a threefold increase at 200 mM over the respective control. The results of this study suggest that natural plant settings of saline habitats are a good source for the isolation of beneficial salt-tolerant bacteria to grow crops under saline conditions.

Description: Agronomy, Vol. 8, Pages 132: Response of Common Bean Genotypes Grown in Soil with Normal or Limited Moisture, with Special Reference to the Nutrient Phosphorus Agronomy doi: 10.3390/agronomy8080132 Authors: Margaret Namugwanya John Stephen Tenywa Erasmus Otabbong Drought and phosphorus deficiency in the soil are the major production limitations of common beans (Phaseolus vulgaris L.) in Sub-Saharan Africa. This study measured the yield responses of low phosphorus-tolerant common beans to drought stress. A field experiment was conducted under two drought conditions codenamed, non-drought-stress (NDS) and drought-stress (DS). The former was located at Mukono Zonal Agricultural Research and Development Institute (MUZARDI) in Mukono District, characterised by rainfall of more than 400 mm season−1. The latter was situated at Wabinyonyi in Nakasongola District, characterised by less than 300 mm season−1; both in central Uganda. Treatments included the two study conditions (NDS and DS); and four test bean genotypes, AFR703-1, AFR 708, JESCA, and MCM 2001, against a local check, K131. A water deficit of 156 mm season−1 was observed in the DS site causing a drought intensity index (DII) of 40%. That pattern contrasted considerably in the NDS site where the actual rainfall did not significantly (p > 0.05) vary from the required water by the bean plant. Whereas genotypes AFR703-1 and AFR708 out-yielded the local check in NDS by 213 and 681 kg ha−1, respectively; their grain yield harvested was comparable to the control yield in DS. When grown under DS, low P-tolerant beans, especially the AFR703-1 and AFR708, survived drought stress through faster development by reducing the number of days to flower, reach physiological maturity and develop seeds. AFR703-1 and AFR708 sufficiently withstand drought stress, and are therefore recommended for inclusion in cropping systems that are characteristically constrained by the combined soils’ P deficiency and/or drought.

Description: Agronomy, Vol. 8, Pages 141: Transcriptomic Analysis of Banana in Response to Phosphorus Starvation Stress Agronomy doi: 10.3390/agronomy8080141 Authors: Rui Xiong Hua Tang Min Xu Can-Bin Zeng Yun Peng Rui He Zhen Yan Zhao Qi Yu Cheng Bananas are an important part of the diets of millions of people around the globe. Low P absorption and use efficiency significantly restrict banana yields. To further explore the molecular mechanisms of P regulation in banana plants, we used RNA sequencing-based transcriptomic analysis for banana plants subjected to Pi deficit stress for 60 days. We detected 1900 significantly differentially expressed genes (DEGs) in aboveground plant parts and 7398 DEGs in root parts under low P stress. Gene ontology (GO) classification analysis showed that 156,291 GO terms belonging to molecular functions, 53,114 GO terms belonging to cellular components, and 228,544 GO terms belonging to biological processes were enriched in the aboveground and root components. A number of DEGs involved in energy metabolism-related processes, signal transduction, control of rhizosphere P activation, and Pi mobilization were found, which were confirmed by quantitative reverse-transcription Polymerase Chain Reaction (qRT-PCR) analysis. At the transcriptomic level, we detected 13 DEGs from different organs and with different functions in the time-course response to phosphorus deficiency stress. These DEGs may include some key genes that regulate the phosphorus network, increasing our understanding of the molecular mechanism of Pi homeostasis in banana. These findings will also help develop biotechnologies to create a variant of banana with more effective Pi absorption and utilization.

Description: Agronomy, Vol. 8, Pages 140: First Report of Amaranthus hybridus with Multiple Resistance to 2,4-D, Dicamba, and Glyphosate Agronomy doi: 10.3390/agronomy8080140 Authors: Ignacio Dellaferrera Eduardo Cortés Elisa Panigo Rafael De Prado Pedro Christoffoleti Mariel Perreta In many countries, Amaranthus hybridus is a widespread weed in agricultural systems. The high prolificacy and invasive capacity as well as the resistance of some biotypes to herbicides are among the complications of handling this weed. This paper reports on the first A. hybridus biotypes with resistance to auxinic herbicides and multiple resistance to auxinic herbicides and the EPSPs inhibitor, glyphosate. Several dose response assays were carried out to determine and compare sensitivity of six population of A. hybridus to glyphosate, 2,4-D, and dicamba. In addition, shikimic acid accumulation and piperonil butoxide effects on 2,4-D and dicamba metabolism were tested in the same populations. The results showed four populations were resistant to dicamba and three of these were also resistant to 2,4-D, while only one population was resistant to glyphosate. The glyphosate-resistant population also showed multiple resistance to auxinic herbicides. Pretreatment with piperonil butoxide (PBO) followed by 2,4-D or dicamba resulted in the death of all individual weeds independent of herbicide or population.

Description: Agronomy, Vol. 8, Pages 93: Production of a Polyclonal Antibody against the Recombinant Coat Protein of the Sugarcane Mosaic Virus and Its Application in the Immunodiagnostic of Sugarcane Agronomy doi: 10.3390/agronomy8060093 Authors: Nurmalasari Darsono Novita Niswatun Azizah Kiky Mey Putranty Natalia Tri Astuti Hardian Susilo Addy Win Darmanto Bambang Sugiharto Sugarcane mosaic virus (SCMV) is a mosaic disease that has spread over sugarcane plantations in Indonesia. The important step to overcome the disease is to detect the pathogen as early as possible. Detection of the pathogen can be achieved using the immunodiagnostic method by employing a specific antibody against the viral coat protein. The objective of this research was to produce a polyclonal antibody using the recombinant coat protein of SCMV, and to test its sensitivity for detection of SCMV in the symptomatic plant. The gene encoding of the coat protein was cloned using the RT-PCR Kit and total RNA isolated from symptomatic sugarcane leaves cultivar PS-881. Nucleotide sequences analysis of the cloned cDNA indicated that the cDNA contained 998 nucleotides and named SCMVCp-cDNA. The cDNA was then inserted into a His-tag expression plasmid of pET28a and overexpressed in Escherichia coli BL21 (DE3) to produce a recombinant protein. The recombinant fused protein SCMVCp was strongly expressed in an insoluble fraction, with a molecular size of around 44 kDa, without the addition of an IPTG inducer. Purification of the recombinant protein using an affinity Ni-NTA resin, followed by SDS-PAGE separation, resulted in a high purity of the protein and used as an antigen to raise the polyclonal antibody in a rabbit. The sensitivity of the antiserum determined by western blot analysis showed that the antiserum was able to detect the recombinant protein at a concentration of 10 ng. The western blot analysis also detected a clear single band of 36.7 kDa of the SCMV coat protein in symptomatic sugarcane leaves and not in healthy leaves. Interestingly, when the sample proteins were prepared using low-speed centrifugation, the corresponding coat protein was detected in a soluble fraction by western blot analysis. Thus, the antiserum was successfully used for indirect-ELISA analysis using the soluble protein fraction. The results provide an easy method to detect and diagnose SCMV infection using the immunodiagnostic.

Description: Agronomy, Vol. 8, Pages 97: Quantitative Response of Soybean Development and Yield to Drought Stress during Different Growth Stages in the Huaibei Plain, China Agronomy doi: 10.3390/agronomy8070097 Authors: Yanqi Wei Juliang Jin Shangming Jiang Shaowei Ning Li Liu To quantitatively access the effects of drought stress during different growth stages of soybean on development process and yield, a pot-culture experiment was conducted in China’s Huaibei Plain with different irrigation treatments over two seasons (2015 and 2016). Two drought stress levels (mild and severe) were applied at four growth stages for the experiment (S: seedling stage; B: branching stage; FPS: flowering and pod-setting stage; and PF: pod-filling stage). The effects of drought stress at different stages on growth and yield were evaluated and compared. Results of this two-year study showed that all growth and yield parameters were significantly affected by the water deficit during the sensitive FPS. Compared to the full irrigation treatment, severe drought stress during FPS caused a 22% loss of final plant height, 61% loss of the leaf area per plant (LAP), and 67% loss of final aboveground dry matter (ADM). Yield components also declined dramatically with water deficits during FPS and PF. Significant seed yield losses of 73–82% per plant were observed in the plants exposed to drought stress during FPS, and were also associated with the highest nonviable pod percentage of 13%. The greatest losses in 100-seed weight (42–48%) were observed under drought stress during PF. A rising trend in response to increasing soil water deficit (SWD) was observed for LAP, yield, and ADM losses. The slope (k) values of these fitting curves varied at different treatments, the highest value of k (7.37 and 8.47 in two years, respectively) was also observed in the sensitive FPS.

Description: Agronomy, Vol. 8, Pages 102: Early-Season Soil Waterlogging and N Fertilizer Sources Impacts on Corn N Uptake and Apparent N Recovery Efficiency Agronomy doi: 10.3390/agronomy8070102 Authors: Gurpreet Kaur Kelly A. Nelson Peter P. Motavalli Soil waterlogging resulting from extreme precipitation events creates anaerobic conditions that may inhibit plant growth and increase N losses. A three-year (2013–2015) field experiment was conducted in poorly-drained claypan soils to assess the effects of waterlogging [0 or 7-days waterlogging at V3 growth stage of corn (Zea mays L.)] and pre-plant application of different N fertilizer sources and post-waterlogging rescue N application (0 or 84 kg N ha−1 of urea plus urease inhibitor (NCU + UI) at V7) on chlorophyll SPAD meter (CM) readings, stomatal conductance, ear leaf and silage N concentrations, N uptake and apparent N recovery efficiency (ARE) of two corn hybrids with varying amounts of flood tolerance. Pre-plant N fertilizer sources included a non-treated control (CO), urea (NCU), urea plus nitrification inhibitor (NCU + NI) and polymer coated urea (PCU) applied at 168 kg N ha−1. In 7-days waterlogged plots, rescue N applications increased N uptake in PCU treatments 33% and 40% in 2013 and 2014, respectively, as well as in NCU by 48% in 2013. In 7-days waterlogged plots which received rescue N applications, NCU and PCU in 2013 resulted in higher N uptake than CO and NCU + NI by 47 to 77 kg ha−1. PCU had higher N uptake than NCU and NCU + NI by 78 and 72 kg ha−1 in 7-days waterlogged plots that received rescue N applications in 2014. Corn hybrid showed no differences in N uptake and ARE in our study. Our results indicate combining pre-plant N fertilizer source selection and rescue N applications may be a strategy to reduce possible decreases in corn N uptake caused by early season soil waterlogging in average rainfall years.

Description: Agronomy, Vol. 8, Pages 103: Genome-Wide Identification and Expression Analysis of Heat Shock Transcription Factor Family in Chenopodium quinoa Willd Agronomy doi: 10.3390/agronomy8070103 Authors: Gongbo Tashi Haoshuang Zhan Guangwei Xing Xi Chang Hong Zhang Xioajun Nie Wanquan Ji Heat shock transcription factor (Hsf) is one of the conserved gene families in plants, playing a crucial role in growth and development, as well as in response to diverse stresses. Although it has been systematically studied in many species, little is known about the Hsf gene family in Chenopodium quinoa, especially those involved in the regulatory network of stress processes. In this study, we identified 23 Hsf genes in quinoa (CqHsfs) through a genome-wide search method based on the latest available genome information. Phylogenetic analysis classified them into three groups, and group A was further divided into nine subgroups, which was supported by conserved domain organizations. Gene structure and multiple sequence alignment analysis revealed that all of the CqHsfs possessed a similar structure organization and were highly conserved in BDB domain. Interaction network analysis identified 13 CqHsfs involved in the network pathway to regulate diverse biological processes. Expression profiles of these CqHsfs were further investigated using the RNA-seq data, and tissue-specific and stress-responsive candidates were identified. Finally, four heat-responsive CqHsfs were selected to validate their expression level through semi-quantitative RT-PCR analysis. This study reported the organization, structure, and expression profiles of the Hsf gene family in quinoa, which will contributes to further functional analysis, and helps to better understand the roles and regulatory mechanism of heat shock factors playing in quinoa and beyond.

Description: Agronomy, Vol. 8, Pages 134: Pattern Recognition Receptors—Versatile Genetic Tools for Engineering Broad-Spectrum Disease Resistance in Crops Agronomy doi: 10.3390/agronomy8080134 Authors: Stefanie Ranf Infestations of crop plants with pathogens pose a major threat to global food supply. Exploiting plant defense mechanisms to produce disease-resistant crop varieties is an important strategy to control plant diseases in modern plant breeding and can greatly reduce the application of agrochemicals. The discovery of different types of immune receptors and a detailed understanding of their activation and regulation mechanisms in the last decades has paved the way for the deployment of these central plant immune components for genetic plant disease management. This review will focus on a particular class of immune sensors, termed pattern recognition receptors (PRRs), that activate a defense program termed pattern-triggered immunity (PTI) and outline their potential to provide broad-spectrum and potentially durable disease resistance in various crop species—simply by providing plants with enhanced capacities to detect invaders and to rapidly launch their natural defense program.

Description: Agronomy, Vol. 8, Pages 136: Microbial Endophytes that Live within the Seeds of Two Tomato Hybrids Cultivated in Argentina Agronomy doi: 10.3390/agronomy8080136 Authors: Silvina Marianela Yanil López Graciela Noemi Pastorino Mario Emilio Ernesto Franco Rocio Medina César Gustavo Lucentini Mario Carlos Nazareno Saparrat Pedro Alberto Balatti Tomato (Solanum lycopersicum L.) is probably the most important vegetable consumed around the world, and like other produce is affected by stresses and diseases that reduce the yield and production. The purpose of this work was to study the phytobiome of the tomato seeds of two hybrids in order to understand first of all whether tomato cultivars host similar groups of organisms, as well as their effect on the community structure, particularly of those microbes with the potential to promote growth and/or control plant pathogens. Different cultivars of tomato (genotypes) host significantly different endophytic communities, which is also reflected at the order level. These communities are particularly rich in spore-forming bacteria that have the ability either to promote plant growth or synthetize antimicrobial compounds that deter plant pathogens. We conclude that the seeds of the tomato cultivars Elpida and Silverio are sources of endophytic bacteria capable of synthetizing antifungal substances that could potentially be used for biocontrol against plant-pathogenic fungi.

Description: Agronomy, Vol. 8, Pages 137: Pod Shattering: A Homologous Series of Variation Underlying Domestication and an Avenue for Crop Improvement Agronomy doi: 10.3390/agronomy8080137 Authors: Ezgi Ogutcen Anamika Pandey Mohd Kamran Khan Edward Marques R. Varma Penmetsa Abdullah Kahraman Eric J. B. von Wettberg In wild habitats, fruit dehiscence is a critical strategy for seed dispersal; however, in cultivated crops it is one of the major sources of yield loss. Therefore, indehiscence of fruits, pods, etc., was likely to be one of the first traits strongly selected in crop domestication. Even with the historical selection against dehiscence in early domesticates, it is a trait still targeted in many breeding programs, particularly in minor or underutilized crops. Here, we review dehiscence in pulse (grain legume) crops, which are of growing importance as a source of protein in human and livestock diets, and which have received less attention than cereal crops and the model plant Arabidopsis thaliana. We specifically focus on the (i) history of indehiscence in domestication across legumes, (ii) structures and the mechanisms involved in shattering, (iii) the molecular pathways underlying this important trait, (iv) an overview of the extent of crop losses due to shattering, and the effects of environmental factors on shattering, and, (v) efforts to reduce shattering in crops. While our focus is mainly pulse crops, we also included comparisons to crucifers and cereals because there is extensive research on shattering in these taxa.

Description: Agronomy, Vol. 8, Pages 145: Impact of High Temperature and Drought Stresses on Chickpea Production Agronomy doi: 10.3390/agronomy8080145 Authors: Viola Devasirvatham Daniel K. Y. Tan Global climate change has caused severe crop yield losses worldwide and is endangering food security in the future. The impact of climate change on food production is high in Australia and globally. Climate change is projected to have a negative impact on crop production. Chickpea is a cool season legume crop mostly grown on residual soil moisture. High temperature and terminal drought are common in different regions of chickpea production with varying intensities and frequencies. Therefore, stable chickpea production will depend on the release of new cultivars with improved adaptation to major events such as drought and high temperature. Recent progress in chickpea breeding has increased the efficiency of assessing genetic diversity in germplasm collections. This review provides an overview of the integration of new approaches and tools into breeding programs and their impact on the development of stress tolerance in chickpea.

Description: Agronomy, Vol. 8, Pages 147: Impact of Climatic Variables on Carbon Content in Sugar Beet Root Agronomy doi: 10.3390/agronomy8080147 Authors: Luis F. Sánchez-Sastre Pablo Martín-Ramos Luis M. Navas-Gracia Salvador Hernández-Navarro Jesús Martín-Gil The impacts of climatic variables on the growth and carbon content of spring sown sugar beet (Beta vulgaris L.) in the Castilla y Leon region (Northwestern Spain) were assessed by analyzing 35 beet crop variables at four sites over two cultivation years. ANOVA analysis allowed to discern that the location was the factor that had the highest effect on those variables. Fertilization treatments only had a significant impact on the variables derived from the quantity of fresh material (leaves), while the beet variety choice influenced the amount of nitrogen in leaves and the carbon to nitrogen ratio. It could be inferred that the percentage of root carbon content depended mostly on the location and that a higher percentage of root carbon content led to a higher content of dry matter, with a positive relationship with the sucrose content for the two types of varieties that were tested. Principal Component Analysis distinguished the climatic factors that most influenced each cultivation area in each cultivation year and provided a clear separation of the data in clusters, evidencing the uniqueness of each site.

Description: Agronomy, Vol. 8, Pages 152: Climate Change, Carbon Dioxide, and Pest Biology, Managing the Future: Coffee as a Case Study Agronomy doi: 10.3390/agronomy8080152 Authors: Lewis H. Ziska Bethany A. Bradley Rebekah D. Wallace Charles T. Bargeron Joseph H. LaForest Robin A. Choudhury Karen A. Garrett Fernando E. Vega The challenge of maintaining sufficient food, feed, fiber, and forests, for a projected end of century population of between 9–10 billion in the context of a climate averaging 2–4 °C warmer, is a global imperative. However, climate change is likely to alter the geographic ranges and impacts for a variety of insect pests, plant pathogens, and weeds, and the consequences for managed systems, particularly agriculture, remain uncertain. That uncertainty is related, in part, to whether pest management practices (e.g., biological, chemical, cultural, etc.) can adapt to climate/CO2 induced changes in pest biology to minimize potential loss. The ongoing and projected changes in CO2, environment, managed plant systems, and pest interactions, necessitates an assessment of current management practices and, if warranted, development of viable alternative strategies to counter damage from invasive alien species and evolving native pest populations. We provide an overview of the interactions regarding pest biology and climate/CO2; assess these interactions currently using coffee as a case study; identify the potential vulnerabilities regarding future pest impacts; and discuss possible adaptive strategies, including early detection and rapid response via EDDMapS (Early Detection & Distribution Mapping System), and integrated pest management (IPM), as adaptive means to improve monitoring pest movements and minimizing biotic losses while improving the efficacy of pest control.

Description: Agronomy, Vol. 8, Pages 151: Water Stress Influence on The Vegetative Period Yield Components of Different Maize Genotypes Agronomy doi: 10.3390/agronomy8080151 Authors: Cassyo de Araujo Rufino Jucilayne Fernandes-Vieira Jesús Martín-Gil José de Souza Abreu Júnior Lizandro Ciciliano Tavares Marciabela Fernandes-Correa Pablo Martín-Ramos Maize is an important food staple in many countries, and is useful in animal feed and many industrial applications. Its productivity is highly sensitive to drought stress, which may occur at any period during its growth cycle. The objective of this work was to compare the water stress influence on the performance of different maize genotypes in critical vegetative stages. Four genotypes of maize (namely a single-cross hybrid (AG 9045), a double-cross hybrid (AG 9011), a triple-cross hybrid (AG 5011), and a variety (AL Bandeirante)) were subjected to a 10-day period without irrigation in the vegetative stages that determine the number of kernel rows and the plant’s ability to take up nutrients and water (V4, V6 and V8). The impact of low water availability was assessed by analyzing plant height, height of the first ear insertion, stem diameter, yield per plant, and number of rows per ear, evincing that the yield per plant was the most sensitive parameter in all the stages. With regard to the influence of the genotype, the single-cross hybrid was demonstrated to be the most resilient to water shortage.

Description: Agronomy, Vol. 8, Pages 161: Delimitation of Agricultural Areas with Natural Constraints in Greece: Assessment of the Dryness Climatic Criterion Using Geostatistics Agronomy doi: 10.3390/agronomy8090161 Authors: Konstantinos X. Soulis Dionissios P. Kalivas Costas Apostolopoulos The Less Favored Areas (LFAs) scheme has existed in various forms since 1975 and it is a broad mechanism supporting rural development in agricultural areas with natural constraints (ANC). Within the programme period 2014–2020, the European Commission developed a common set of biophysical criteria (soil, climate, and terrain) to meet the requirement for a robust and harmonized approach of delimiting ANC throughout the EU Member States. Soil and terrain criteria can be derived directly from soil maps using geospatial analysis techniques based on the provided guidelines. However, the assessment of climatic criteria can be challenging especially in regions characterized by increased spatial variability and data scarcity. In this paper, the assessment of the dryness climatic criterion in a data-scarce region (Greece) as well as the challenges, limitations, and solutions are presented. Daily data-series from 140 meteorological stations for a 30-year reference period were analyzed and the spatial distribution of the precipitation and the potential evapotranspiration for each year were estimated in order to make the final assessment of the dryness criterion. Climate variability and the presence of trends were investigated as well. The obtained results indicated that most of the utilized agricultural area is affected by dryness due to a combination of low precipitation and high evapotranspiration rates. The extreme spatial variability especially in precipitation was also highlighted. An important temporal variability was observed as well, including indications of decreasing trends in precipitation and aridity index. Climate variability and possible trends should be investigated in more detail using longer time series in order to evaluate their impact in agricultural production.

Description: Agronomy, Vol. 8, Pages 169: How Does Sowing Rate Affect Plant and Stem Density, Forage Yield, and Nutritive Value in Glyphosate-Tolerant Alfalfa? Agronomy doi: 10.3390/agronomy8090169 Authors: Marisol T. Berti Dulan Samarappuli The recommended sowing rate of alfalfa (Medicago sativa L.) is about 10 kg pure live seed ha−1, but it is debated if increasing the sowing rate enhances forage yield and quality in the sowing year. This study was conducted to: (i) determine the optimal sowing rate to maximize forage yield; and (ii) determine the relationship between plant and stem density with forage yield and nutritive value. Experiments were conducted at three sites in North Dakota between 2013 and 2016. Six sowing rates [1, 5, 10, 15, 20, and 25 kg ha−1 pure live seed (PLS)] were evaluated. Results indicated that total forage yield in the sowing year was lower only with the lowest sowing rate. Maximum total forage yield in the sowing, first, second, and third production years was obtained with 73, 52, 37, and 36 plants m−2 and 575, 495, 435, and 427 stems m−2, respectively. In the sowing and first production year, both plant and stem density predicted forage yield similarly. In older stands, stem density predicted forage yield slightly better. Forage nutritive value was similar among sowing rates indicating an increase in sowing rate does not enhance forage nutritive value. In conclusion, increasing the sowing rate above the recommended rate (10 kg PLS ha−1) does not increase forage yield or quality.

Description: Agronomy, Vol. 8, Pages 168: Imbalance Water Deficit Improves the Seed Yield and Quality of Soybean Agronomy doi: 10.3390/agronomy8090168 Authors: Nasir Iqbal Sajad Hussain Xiao-Wen Zhang Cai-Qiong Yang Muhammad Ali Raza Jun-Cai Deng Shoaib Ahmad Muhammad Ahsan Ashgar Jing Zhang Wenyu Yang Jiang Liu Water imbalance condition (WIC) in a maize-soybean relay intercropping system is the main abiotic stress limiting biomass production and seed yield and, consequently, seed-quality. This experiment was started to study the effects of WIC on soybean, in which two soybean genotypes ND12 and C103 were grown in pots with roots split equally between two soil column and six WIC treatments (%) T1 (100), T2, (100:50), T3 (100:20), T4 (50:50), T5 (50:20), and T6 (20:20) field capacity on both sides of soybean roots were used. Results showed that both genotypes responded significantly to WIC treatments for all the parameters; however, the level of response differed between genotypes. Maximum osmoprotectants (except proline), biomass, yield and yield-related traits and superior seed quality were observed with ND12. Among WIC treatments, T2 and T3 produced 94% and 85%, and 93% and 81% of T1 biomass and yield, respectively. Similarly, treatments T2 and T3 also improved the oil quality by maintaining the content of unsaturated fatty acids and isoflavone content, while opposite trends were observed for protein content. Overall, moderate water reduction (T2 and T3) can improve soybean seed-quality and by selecting drought-resistant genotypes we can increase the soybean yield under intercropping systems.

Description: Agronomy, Vol. 8, Pages 174: Molecular and Genetic Bases of Fruit Firmness Variation in Blueberry—A Review Agronomy doi: 10.3390/agronomy8090174 Authors: Francesco Cappai Juliana Benevenuto Luís Felipe V. Ferrão Patricio Munoz Blueberry (Vaccinium spp.) has been recognized worldwide as a valuable source of health-promoting compounds, becoming a crop with some of the fastest rising consumer demand trends. Fruit firmness is a key target for blueberry breeding as it directly affects fruit quality, consumer preference, transportability, shelf life, and the ability of cultivars to be machine harvested. Fruit softening naturally occurs during berry development, maturation, and postharvest ripening. However, some genotypes are better at retaining firmness than others, and some are crispy, which is a putatively extra-firmness phenotype that provides a distinct eating experience. In this review, we summarized important studies addressing the firmness trait in blueberry, focusing on physiological and molecular changes affecting this trait at the onset of ripening and also the genetic basis of firmness variation across individuals. New insights into these topics were also achieved by using previously available data and historical records from the blueberry breeding program at the University of Florida. The complex quantitative nature of firmness in an autopolyploid species such as blueberry imposes additional challenges for the implementation of molecular techniques in breeding. However, we highlighted some recent genomics-based studies and the potential of a QTL (Quantitative Trait Locus) mapping analysis and genome editing protocols such as CRISPR/Cas9 to further assist and accelerate the breeding process for this important trait.

Description: Agronomy, Vol. 8, Pages 177: Adaptability and Forage Characterization of Finger Millet Accessions in U.S. Southern Great Plains Agronomy doi: 10.3390/agronomy8090177 Authors: Gurjinder S. Baath Brian K. Northup Prasanna H. Gowda Alexandre C. Rocateli Kenneth E. Turner Low forage quality of available perennial warm-season grasses during mid-summer through late summer affects the production of stocker cattle in the U.S. Southern Great Plains (SGP). Finger millet (Eleusine coracana Gaertn L.), which is a drought tolerant annual grass, could be a promising forage for the SGP. This field study assessed the adaptability and forage characteristics of 11 finger millet accessions originally sourced (1964–1981) from different parts of the world. Results of this study suggested that finger millet can generate forage yields ranging from 5.0 to 12.3 Mg ha−1 165 days after planting. Finger millet forage contained 105 to 156 g kg−1 crude protein, 598 to 734 g kg−1 neutral detergent fiber, 268 to 382 g kg−1 acid detergent fiber, 597 to 730 g kg−1 in vitro true digestibility, and 387 to 552 g kg−1 neutral detergent fiber digestibility. Ten of the 11 accessions flowered and produced grains with yields varying from 60 to 1636 kg ha−1. Overall, finger millet has the potential to serve as an alternative crop for the production of forage and possibly grain in the SGP. Further research needs to be focused on developing strategies for agronomic management and evaluating the capacity of finger millet under different grazing and hay production settings in the SGP.

Description: Agronomy, Vol. 8, Pages 188: Polyaspartic Acid Improves Maize (Zea mays L.) Seedling Nitrogen Assimilation Mainly by Enhancing Nitrate Reductase Activity Agronomy doi: 10.3390/agronomy8090188 Authors: Qingyan Wang Huihui Tang Guangyan Li Hui Dong Xuerui Dong Yanli Xu Zhiqiang Dong Improvement of nitrogen use efficiency is of great importance in maize (Zea mays L.) production. In the present study, an eco-friendly growth substance, polyaspartic acid (PASP), was applied to maize seedlings grown with different nitrate (NO3−) doses by foliar spraying, aimed at evaluating its effects on maize nitrogen assimilation at both the physiological and molecular level. The results showed that PASP promoted biomass and nitrogen accumulation in maize seedlings, especially under low NO3− doses. Among different NO3− conditions, the most noticeable increase in plant biomass by PASP addition was observed in seedlings grown with 1 mmol L−1 NO3−, which was a little less than the optimum concentration (2 mmol L−1) for plant growth. Furthermore, the total nitrogen accumulation increased greatly with additions of PASP to plants grown under suboptimal NO3− conditions. The promotion of nitrogen assimilation was mostly due to the increase of nitrate reductase (NR) activities. The NR activities in seedlings grown under low NO3− doses (0.5 and 1.0 mmol L−1) were extremely increased by PASP, while the activities of glutamine synthetase (GS), aspartate aminotransferase (AspAT), and alanine aminotransferase (AlaAT) were slightly changed. Moreover, the regulation of PASP on NR activity was most probably due to the promotion of the protein accumulation rather than gene expression. Accumulation of NR protein was similarly affected as NR activity, which was markedly increased by PASP treatment. In conclusion, the present study provides insights into the promotion by PASP of nitrogen assimilation and identifies candidate regulatory enzymatic mechanisms, which warrant further investigation with the use of PASP in promoting nitrogen utilization in crops.

Description: Agronomy, Vol. 8, Pages 187: Effect of Unmanned Aerial Vehicle Flight Height on Droplet Distribution, Drift and Control of Cotton Aphids and Spider Mites Agronomy doi: 10.3390/agronomy8090187 Authors: Zhaoxia Lou Fang Xin Xiaoqiang Han Yubin Lan Tianzhu Duan Wei Fu Unmanned aerial vehicles (UAVs), as emerging plant protection machinery, have the advantages of high operational efficiency, high speed, and low drift. The current study aimed to elucidate the characteristics of droplet distribution and drift, control efficiency on cotton aphids and spider mites, and attachment and absorption of cotton leaves during UAV spraying. Kromekote card and filter paper are used as samplers to collect droplets, and the droplet density, coverage rate, deposition, and drift percentage are statistically analyzed. The pooled results showed that the droplet uniformity, the droplet coverage rate, the deposition, and the drifting ability are higher when the UAV flight height was 2 m. The control effects by UAV spraying on cotton aphids and spider mites were 63.7% and 61.3%, respectively. These values are slightly inferior to those obtained through boom spraying. Cotton leaf attachment and absorption of spirodiclofen after UAV spraying were slightly lower than those after boom spraying, therefore, the control efficiency of cotton pests is slightly different. According to the different flight height operations by the UAV sprayer, the drift capability of the droplets at 2 m flight height was large, and the droplet uniformity and deposition were satisfactory. The research results could provide the theoretical basis and technical support for UAV operation.

Description: Agronomy, Vol. 8, Pages 190: District Scale GHG Emission Indicators for Canadian Field Crop and Livestock Production Agronomy doi: 10.3390/agronomy8090190 Authors: James A. Dyer Xavier P. C. Vergé Raymond L. Desjardins Devon E. Worth The three main farm products from Canadian agriculture, i.e., proteins, vegetable oils, and carbohydrates, account for 98% of the land in annual crops in Canada. The intensities and efficiencies of these field crops in relation to their Greenhouse Gas (GHG) emissions were assessed for their value as land use change indicators. To facilitate spatial comparisons, this assessment was carried out at the Ecodistrict (ED) scale. The Unified Livestock Industry and Crop Emissions Estimation System (ULICEES) model was modified to operate at the ED scale, and used to quantify the GHG emission intensity of protein. GHG emissions were also calculated for plant products not used for livestock feed. The livestock GHG emissions and GHG-protein intensities estimated using ED scale inputs to ULICEES were reasonably close to GHG-protein intensities generated by the version of ULICEES driven by provincial scale census data. Carbohydrates were split into two groups, i.e., whether or not they supported livestock. Annual farm product data at 5-year intervals were used to generate GHG emissions from all farm operations. The range of GHG emissions from all farm operations in Western Canada was from 42 to 54 Mt CO2e between in 1991 and 2011, while GHG emissions from livestock ranged from 22 to 34 Mt CO2e over the same period. The Eastern Canadian GHG emissions from all farm operations declined gradually from 24 to 22 Mt CO2e over the period, with most of the eastern GHG emissions being from livestock. Ruminant livestock accounted for most of the livestock GHG emissions, particularly in the west. Provincial scale GHG emission efficiencies of the four farm product groups were assessed on a per-unit of GHG emissions basis for 2006. The most GHG-efficient province for protein was Ontario, whereas the most GHG-efficient province for all three plant products was Saskatchewan. The coastal provinces were the least GHG-efficient sources of all four farm product groups.

Description: Agronomy, Vol. 8, Pages 193: Agronomic Advancement in Tillage, Crop Rotation, Soil Health, and Genetic Gain in Durum Wheat Cultivation: A 17-Year Canadian Story Agronomy doi: 10.3390/agronomy8090193 Authors: Lin Li Yining Niu Yuefeng Ruan Ron M. DePauw Asheesh K. Singh Yantai Gan The global demands for various grains, including durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn.), are expected to increase substantially in the coming years, due to the ever-growing human population’s needs for food, feed, and fuel. Thus, providing consistent or increased durum grain to the world market is one of the priorities for policy-makers, researchers, and farmers. What are the major achievements in agronomic advancement for durum wheat cultivation in recent decades? How might the current cropping systems be improved to increase crop yield and quality and improve resource use efficiencies while minimizing input costs and decreasing negative impact on the environment? Canada is one of the major durum wheat producers in the world, as Canada contributes about 50% to global trade of durum grain. Canada’s research achievements in durum wheat might serve as a guide for advancing the cultivation of the crop in other regions/countries on the planet. This review summarizes the major Canadian research findings in the aspects of durum wheat agronomics during the period 2001 to 2017 years. It highlights the main advancements in seeding and tillage, crop rotation and diversification, and use of pulse-induced microbiomes to improve soil health and feedback mechanisms. The genetic gain and breeding for resistance against abiotic and biotic stresses are discussed. Finally, we identified the main constraints and suggested some near-term research priorities. The research findings highlighted in this review will be of use for other areas on the planet to increase durum wheat productivity, improve soil fertility and health, and enhance long-term sustainability.

Description: Agronomy, Vol. 8, Pages 196: Prediction of Sugarcane Yield Based on NDVI and Concentration of Leaf-Tissue Nutrients in Fields Managed with Straw Removal Agronomy doi: 10.3390/agronomy8090196 Authors: Izaias Pinheiro Lisboa Júnior Melo Damian Maurício Roberto Cherubin Pedro Paulo Silva Barros Peterson Ricardo Fiorio Carlos Clemente Cerri Carlos Eduardo Pellegrino Cerri The total or partial removal of sugarcane (Saccharum spp. L.) straw for bioenergy production may deplete soil quality and consequently affect negatively crop yield. Plants with lower yield potential may present lower concentration of leaf-tissue nutrients, which in turn changes light reflectance of canopy in different wavelengths. Therefore, vegetation indexes, such as the normalized difference vegetation index (NDVI) associated with concentration of leaf-tissue nutrients could be a useful tool for monitoring potential sugarcane yield changes under straw management. Two sites in São Paulo state, Brazil were utilized to evaluate the potential of NDVI for monitoring sugarcane yield changes imposed by different straw removal rates. The treatments were established with 0%, 25%, 50%, and 100% straw removal. The data used for the NDVI calculation was obtained using satellite images (CBERS-4) and hyperspectral sensor (FieldSpec Spectroradiometer, Malvern Panalytical, Almelo, Netherlands). Besides sugarcane yield, the concentration of the leaf-tissue nutrients (N, P, K, Ca, and S) were also determined. The NDVI efficiently predicted sugarcane yield under different rates of straw removal, with the highest performance achieved with NDVI derived from satellite images than hyperspectral sensor. In addition, leaf-tissue N and P concentrations were also important parameters to compose the prediction models of sugarcane yield. A prediction model approach based on data of NDVI and leaf-tissue nutrient concentrations may help the Brazilian sugarcane sector to monitor crop yield changes in areas intensively managed for bioenergy production.

Description: Agronomy, Vol. 8, Pages 202: Mitigation Potential and Yield-Scaled Global Warming Potential of Early-Season Drainage from a Rice Paddy in Tamil Nadu, India Agronomy doi: 10.3390/agronomy8100202 Authors: Aung Zaw Oo Shigeto Sudo Kazuyuki Inubushi Umamageswari Chellappan Akinori Yamamoto Keitsuke Ono Masayoshi Mano Sachiko Hayashida Vanitha Koothan Takeshi Osawa Yukio Terao Jothimani Palanisamy Elayakumar Palanisamy Ravi Venkatachalam Water-intensive systems of rice cultivation are facing major challenges to increase rice grain yield under conditions of water scarcity while also reducing greenhouse gas (GHG) emissions. The adoption of effective irrigation strategies in the paddy rice system is one of the most promising options for mitigating GHG emissions while maintaining high crop yields. To evaluate the effect of different alternate wetting and drying (AWD) irrigation strategies on GHG emissions from paddy rice in dry and wet seasons, a field experiment was conducted at the Tamil Nadu Rice Research Institute (TRRI), Aduthurai, Tamil Nadu, India. Four irrigation treatments were included: One-AWD (one early drying period), Two-AWD (two early drying periods), Full-AWD (wetting and drying cycles throughout the rice season), and CF (continuous flooding). Different rice varieties were also tested in the experiment. In this study, we emphasized one factor (irrigation effect) that affects the dependent variable. The results show that early AWD treatments reduced methane (CH4) emissions by 35.7 to 51.5% in dry season and 18.5 to 20.1% in wet season, while full-AWD practice reduced CH4 emissions by 52.8 to 61.4% compared with CF. Full-AWD in dry season not only significantly reduced CH4 emission during that season, it also resulted in the decline of the early season emission in the succeeding wet season. Global warming potential (GWP) and yield-scaled GWP were reduced by early or full season AWD in both rice seasons. The GWP value from nitrous oxide (N2O) was relatively low compared to that from CH4 in both rice seasons. Rice yield was not affected by irrigation treatments although varietal differences in grain and straw yields were observed in both rice seasons. This study demonstrated that early season water managements are also effective in reducing CH4 and total GHG emissions without affecting rice yield.

Description: Agronomy, Vol. 8, Pages 199: Forage Warm-Season Legumes and Grasses Intercropped with Corn as an Alternative for Corn Silage Production Agronomy doi: 10.3390/agronomy8100199 Authors: Renata La Guardia Nave Michael Dereck Corbin Intercropping of forage grasses and legumes can increase forage productivity and nutritive value; however, intercropping of corn with warm-season forages has not yet been studied in southeast U.S., thus requiring more information. The purpose of this study was to determine the yield and nutritive value potential of warm-season annual forages intercropped with corn (Zea mays L.) for silage production. Crabgrass [Digitaria sanguinalis (L.)] is considered a weed for corn production systems; however, our study shows that if crabgrass is interseeded with corn, it does not compete for resources and can maintain high corn yields. Forage mass for sunn hemp (Crotalaria juncea L.) was higher than that of cowpea [Vigna unguiculata (L.) Walp.] and crabgrass in 2016, due to a drought in spring and summer, giving sunn hemp a competitive advantage. Crude protein content was higher for cowpea as compared to crabgrass and sunn hemp, due to cowpea’s ability to maintain its vegetative stage and high N-fixation, when compared to crabgrass and sunn hemp. Despite differences in the mass of the intercropped forages, the total herbage mass of the produced silage did not differ in 2016 and 2017. Intercropped forages can be harvested and ensiled with corn for silage production or can be left with the corn residue after harvesting to be grazed on in integrated crop-livestock systems.

Description: Meeting global demand of safe and healthy food for the ever-increasing population now and into the future is currently a crucial challenge. Increasing crop production by preserving environment and mitigating climate change should thus be the main goal of today’s agriculture. Conventional farming is characterized by use of high-yielding varieties, irrigation water, chemical fertilizers and synthetic pesticides to increase yields. However, due to either over- or misuse of chemical fertilizers or pesticides in many agro-ecosystems, such farming is often blamed for land degradation and environmental pollution and for adversely affecting the health of humans, plants, animals and aquatic ecosystems. Of all inputs required for increased agricultural production, nutrients are considered to be the most important ones. Organic farming, with use of organic sources of nutrients, is proposed as a sustainable strategy for producing safe, healthy and cheaper food and for restoring soil fertility and mitigating climate change. However, there are several myths and controversies surrounding the use of organic versus inorganic sources of nutrients. The objectives of this paper are: (i) to clarify some of the myths or misconceptions about organic versus inorganic sources of nutrients and (ii) to propose alternative solutions to increase on-farm biomass production for use as organic inputs for improving soil fertility and increasing crop yields. Common myths identified by this review include that organic materials/fertilizers can: (i) supply all required macro- and micro-nutrients for plants; (ii) improve physical, chemical and microbiological properties of soils; (iii) be applied universally on all soils; (iv) always produce quality products; (v) be cheaper and affordable; and (vi) build-up of large amount of soil organic matter. Other related myths are: “legumes can use entire amount of N2 fixed from atmosphere” and “bio-fertilizers increase nutrient content of soil.” Common myths regarding chemical fertilizers are that they: (i) are not easily available and affordable, (ii) degrade land, (iii) pollute environment and (iv) adversely affect health of humans, animals and agro-ecosystems. The review reveals that, except in some cases where higher yields (and higher profits) can be found from organic farming, their yields are generally 20–50% lower than that from conventional farming. The paper demonstrates that considering the current organic sources of nutrients in the developing countries, organic nutrients alone are not enough to increase crop yields to meet global food demand and that nutrients from inorganic and organic sources should preferably be applied at 75:25 ratio. The review identifies a new and alternative concept of Evergreen Agriculture (an extension of Agroforestry System), which has potential to supply organic nutrients in much higher amounts, improve on-farm soil fertility and meet nutrient demand of high-yielding crops, sequester carbon and mitigate greenhouse gas emissions, provide fodder for livestock and fuelwood for farmers and has potential to meet global food demand. Evergreen Agriculture has been widely adapted by tens of millions of farmers in several African countries and the review proposes for evaluation and scaling-up of such technology in Asian and Latin American countries too.

Description: The use of plant growth-promoting microorganisms (PGPMs) as bio-effectors (BEs) to improve the nutrient acquisition of crops has a long history. However, limited reproducibility of the expected effects still remains a major challenge for practical applications. Based on the hypothesis that the expression of PGPM effects depends on soil type and the properties of the applied fertilizers, in this study, the performance of selected microbial inoculants was investigated for two contrasting low-fertility soils supplied with different organic and inorganic fertilizers. Greenhouse experiments were conducted with tomato on an alkaline sandy loam of pH 7.8 and an acidic loamy sand of pH 5.6 with limited phosphate (P) availability. Municipal waste compost, with and without poultry manure (PM), rock phosphate (RP), stabilized ammonium, and mineral nitrogen, phosphorus and potassium (NPK) fertilization were tested as fertilizer variants. Selected strains of Bacillus amyloliquefaciens (Priest et al. 1987) Borriss et al. 2011 (FZB42) and Trichoderma harzianum Rifai (OMG16) with proven plant growth-promoting potential were used as inoculants. On both soils, P was identified as a major limiting nutrient. Microbial inoculation selectively increased the P utilization in the PM-compost variants by 116% and 56% on the alkaline and acidic soil, while RP utilization was increased by 24%. This was associated with significantly increased shoot biomass production by 37–42%. Plant growth promotion coincided with a corresponding stimulation of root growth, suggesting improved spatial acquisition of soluble soil P fractions, associated also with improved acquisition of nitrogen (N), potassium (K), magnesium (Mg), and calcium (Ca). There was no indication for mobilization of sparingly soluble Ca phosphates via rhizosphere acidification on the alkaline soil, and only mineral NPK fertilization reached a sufficient P status and maximum biomass production. However, on the moderately acidic soil, FZB42 significantly stimulated plant growth of the variants supplied with Ca–P in the form of RP + stabilized ammonium and PM compost, which was equivalent to NPK fertilization; however, the P nutritional status was sufficient only in the RP and NPK variants. The results suggest that successful application of microbial biofertilizers requires more targeted application strategies, considering the soil properties and compatible fertilizer combinations.

Description: Pre-harvest sprouting (PHS) constrains wheat production worldwide by reducing both wheat grain yield and end-use quality. TaPHS1 on wheat chromosome 3AS and TaMKK3-A on chromosome 4AL are two cloned genes with major effects on PHS resistance and they are independent from grain color (GC). In this study, we used marker-assisted backcrossing (MAB) to introgress TaPHS1 and TaMKK3-A from two PHS resistant sources—‘Tutoumai A’ and ‘AUS1408′—into a sprouting-susceptible white wheat line, NW97S186. Progeny were tested in four environments to investigate individual and combined effects of those two genes. TaPHS1 significantly reduced PHS and its effect on PHS varied with environments and gene sources. In contrast, the TaMKK3-A gene also significantly reduced PHS but its effectiveness was influenced by environments. The two genes had additive effects on PHS resistance, indicating pyramiding those two quantitative trait lici (QTLs) could increase PHS resistance. The additive effects were greater in a mild environment, such as a greenhouse, than in a dry and hot environment during maturation.

Description: Synchrony between soil mineral nitrogen (N) supply and crop N demand is important for optimal plant growth. Excessively wet conditions expose poorly drained soils to an increased potential of N loss and reduced N use efficiency. A two-year experiment with wheat (Triticum aestivum L.) was initiated in 2014 and concluded in 2016 in northeastern Missouri in the United States (USA). The objective of this experiment was to evaluate the effects of nitrapyrin and pronitridine nitrification inhibitors (NI) applied as an early or late-split application timing (40:60%) of 79 kg N ha−1 or 112 kg N ha−1 on winter wheat soil and plant N status, as well as grain yield. Both NIs had no effect (p = 0.3917) on yield, while there was an interaction between year and the urea ammonium nitrate (UAN) rate on grain yield. Yields were similar (3550 kg ha−1 to 3686 kg ha−1) in 2015 between UAN application rates. UAN at 112 kg N ha−1 resulted in a 551 kg ha−1 greater yield than UAN at 79 kg N ha−1 in 2016. Nitrapyrin and pronitridine did not significantly affect soil ammonium or nitrate–N concentrations at depths of 0–15 cm and 16–30 cm compared to the absence of NI over the period of three months after application. Nitrapyrin with UAN at 112 kg N ha−1 had the highest grain test weight. Further testing of these NIs in combination with UAN for winter wheat production is needed under different climatic and environmental conditions to develop comprehensive management recommendations.

Description: The total or partial removal of sugarcane (Saccharum spp. L.) straw for bioenergy production may deplete soil quality and consequently affect negatively crop yield. Plants with lower yield potential may present lower concentration of leaf-tissue nutrients, which in turn changes light reflectance of canopy in different wavelengths. Therefore, vegetation indexes, such as the normalized difference vegetation index (NDVI) associated with concentration of leaf-tissue nutrients could be a useful tool for monitoring potential sugarcane yield changes under straw management. Two sites in São Paulo state, Brazil were utilized to evaluate the potential of NDVI for monitoring sugarcane yield changes imposed by different straw removal rates. The treatments were established with 0%, 25%, 50%, and 100% straw removal. The data used for the NDVI calculation was obtained using satellite images (CBERS-4) and hyperspectral sensor (FieldSpec Spectroradiometer, Malvern Panalytical, Almelo, Netherlands). Besides sugarcane yield, the concentration of the leaf-tissue nutrients (N, P, K, Ca, and S) were also determined. The NDVI efficiently predicted sugarcane yield under different rates of straw removal, with the highest performance achieved with NDVI derived from satellite images than hyperspectral sensor. In addition, leaf-tissue N and P concentrations were also important parameters to compose the prediction models of sugarcane yield. A prediction model approach based on data of NDVI and leaf-tissue nutrient concentrations may help the Brazilian sugarcane sector to monitor crop yield changes in areas intensively managed for bioenergy production.

Description: The global demands for various grains, including durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn.), are expected to increase substantially in the coming years, due to the ever-growing human population’s needs for food, feed, and fuel. Thus, providing consistent or increased durum grain to the world market is one of the priorities for policy-makers, researchers, and farmers. What are the major achievements in agronomic advancement for durum wheat cultivation in recent decades? How might the current cropping systems be improved to increase crop yield and quality and improve resource use efficiencies while minimizing input costs and decreasing negative impact on the environment? Canada is one of the major durum wheat producers in the world, as Canada contributes about 50% to global trade of durum grain. Canada’s research achievements in durum wheat might serve as a guide for advancing the cultivation of the crop in other regions/countries on the planet. This review summarizes the major Canadian research findings in the aspects of durum wheat agronomics during the period 2001 to 2017 years. It highlights the main advancements in seeding and tillage, crop rotation and diversification, and use of pulse-induced microbiomes to improve soil health and feedback mechanisms. The genetic gain and breeding for resistance against abiotic and biotic stresses are discussed. Finally, we identified the main constraints and suggested some near-term research priorities. The research findings highlighted in this review will be of use for other areas on the planet to increase durum wheat productivity, improve soil fertility and health, and enhance long-term sustainability.

Description: The present study aimed to characterize the simple sequence repeat markers in cotton using the cotton expressed sequence tags. A total of 111 EST-SSR polymorphic molecular markers with trinucleotide motifs were used to evaluate the 79 accessions of Gossypium L., (G. darwinii, 59 and G. barbadense, 20) collected from the Galapagos Islands. The allele number ranged from one to seven, with an average value of 2.85 alleles per locus, while polymorphism information content values varied from 0.008 to 0.995, with an average of 0.520. The discrimination power ranks high for the majority of the SSRs, with an average value of 0.98. Among 111 pairs of EST-SSRs and gSSRs, a total of 49 markers, comprising nine DPLs, one each of MonCGR, MUCS0064, and NAU1028, and 37 SWUs (D-genome), were found to be the best matched hits, similar to the 155 genes identified by BLASTx in the reference genome of G. barbadense, G. arboreum L., and G. raimondii Ulbr. Related genes GOBAR_DD21902, GOBAR_DD15579, GOBAR_DD27526, and GOBAR_AA04676 revealed highly significant expression 10, 15, 18, 21, and 28 days post-anthesis of fiber development. The identified EST-SSR and gSSR markers can be effectively used for mapping functional genes of segregating cotton populations, QTL identification, and marker-assisted selection in cotton breeding programs.

Description: Improvement of nitrogen use efficiency is of great importance in maize (Zea mays L.) production. In the present study, an eco-friendly growth substance, polyaspartic acid (PASP), was applied to maize seedlings grown with different nitrate (NO3−) doses by foliar spraying, aimed at evaluating its effects on maize nitrogen assimilation at both the physiological and molecular level. The results showed that PASP promoted biomass and nitrogen accumulation in maize seedlings, especially under low NO3− doses. Among different NO3− conditions, the most noticeable increase in plant biomass by PASP addition was observed in seedlings grown with 1 mmol L−1 NO3−, which was a little less than the optimum concentration (2 mmol L−1) for plant growth. Furthermore, the total nitrogen accumulation increased greatly with additions of PASP to plants grown under suboptimal NO3− conditions. The promotion of nitrogen assimilation was mostly due to the increase of nitrate reductase (NR) activities. The NR activities in seedlings grown under low NO3− doses (0.5 and 1.0 mmol L−1) were extremely increased by PASP, while the activities of glutamine synthetase (GS), aspartate aminotransferase (AspAT), and alanine aminotransferase (AlaAT) were slightly changed. Moreover, the regulation of PASP on NR activity was most probably due to the promotion of the protein accumulation rather than gene expression. Accumulation of NR protein was similarly affected as NR activity, which was markedly increased by PASP treatment. In conclusion, the present study provides insights into the promotion by PASP of nitrogen assimilation and identifies candidate regulatory enzymatic mechanisms, which warrant further investigation with the use of PASP in promoting nitrogen utilization in crops.

Description: Thousand kernel weight (TKW) is an important parameter for the evaluation of grain yield. The traditional measurement method relies on manual steps: weighing and counting. In this paper, we developed a system for the automated evaluation of thousand kernel weight that combines a weighing module and Android devices, called “gainTKW”. The system is able to collect the weight information from the weighing module through a serial port using the RS232-micro USB cable. In the imaging process, we adopt a k-means clustering segmentation algorithm to solve the problem of uneven lighting. We used the marker-controlled watershed algorithm and area threshold method to count the number of kernels that are touching one another. These algorithms were implemented based on the OpenCV (Open Source Computer Vision) libraries. The system tested kernel images of six species taken with the Android device under different lighting conditions. The algorithms in this study can solve the segmentation problems caused by shadows, as well. The appropriate numbers of kernels, of different species, are counted with an error ratio upper limit of 3%. The application is convenient and easy to operate. For the experiments, we can prove the efficiency and accuracy of the developed system by comparing the results between the manual method and the proposed application.

Description: Low forage quality of available perennial warm-season grasses during mid-summer through late summer affects the production of stocker cattle in the U.S. Southern Great Plains (SGP). Finger millet (Eleusine coracana Gaertn L.), which is a drought tolerant annual grass, could be a promising forage for the SGP. This field study assessed the adaptability and forage characteristics of 11 finger millet accessions originally sourced (1964–1981) from different parts of the world. Results of this study suggested that finger millet can generate forage yields ranging from 5.0 to 12.3 Mg ha−1 165 days after planting. Finger millet forage contained 105 to 156 g kg−1 crude protein, 598 to 734 g kg−1 neutral detergent fiber, 268 to 382 g kg−1 acid detergent fiber, 597 to 730 g kg−1 in vitro true digestibility, and 387 to 552 g kg−1 neutral detergent fiber digestibility. Ten of the 11 accessions flowered and produced grains with yields varying from 60 to 1636 kg ha−1. Overall, finger millet has the potential to serve as an alternative crop for the production of forage and possibly grain in the SGP. Further research needs to be focused on developing strategies for agronomic management and evaluating the capacity of finger millet under different grazing and hay production settings in the SGP.

Description: Monitoring and improving environmental stress in crops is vital for the sustainable development of agriculture and food security. Traditional experimental methods are costly and time-consuming, yet crop growth models focus mainly only on water and nutrient stresses. In this study, a new World Food Studies (WOFOST) model, WOFOST-ES, was developed by the addition of a general environmental stress factor (ES). To calibrate and validate WOFOST-ES, two-year micro-plot experiments and one-year field experiments with sunflower were conducted in the Hetao Irrigation District, China. The results of the micro-plot experiments indicated that the WOFOST model failed to simulate sunflower growth correctly but that the WOFOST-ES model was highly accurate in simulating both yield (R2 = 0.99, root mean square error (RMSE) = 56 kg/ha) and leaf area index (LAI) (R2 = 0.86, RMSE = 0.44). A statistical method for estimating ESs based on the dominant stress factor (salt at our study site) was also proposed as a supplemental tool for WOFOST-ES, and micro-plot and field experiments conducted in 2013 and 2017 both proved acceptable accuracy of the statistical method when using WOFOST-ES. Comparison between ESs and the water and salt stress factors of Feddes-type stress reduction functions indicated that ESs failed to reveal actual environmental stresses during the sunflower seeding stage but did reflect other environmental stresses in addition to water and salt during the bud, flowering, and maturity stages. Although the present WOFOST-ES model proved to be accurate, stable, and practical, future studies should be performed, focusing on the physical separation of ESs, their mechanistic quantification, and their evaluation at small time steps using more observations.

Description: The Less Favored Areas (LFAs) scheme has existed in various forms since 1975 and it is a broad mechanism supporting rural development in agricultural areas with natural constraints (ANC). Within the programme period 2014–2020, the European Commission developed a common set of biophysical criteria (soil, climate, and terrain) to meet the requirement for a robust and harmonized approach of delimiting ANC throughout the EU Member States. Soil and terrain criteria can be derived directly from soil maps using geospatial analysis techniques based on the provided guidelines. However, the assessment of climatic criteria can be challenging especially in regions characterized by increased spatial variability and data scarcity. In this paper, the assessment of the dryness climatic criterion in a data-scarce region (Greece) as well as the challenges, limitations, and solutions are presented. Daily data-series from 140 meteorological stations for a 30-year reference period were analyzed and the spatial distribution of the precipitation and the potential evapotranspiration for each year were estimated in order to make the final assessment of the dryness criterion. Climate variability and the presence of trends were investigated as well. The obtained results indicated that most of the utilized agricultural area is affected by dryness due to a combination of low precipitation and high evapotranspiration rates. The extreme spatial variability especially in precipitation was also highlighted. An important temporal variability was observed as well, including indications of decreasing trends in precipitation and aridity index. Climate variability and possible trends should be investigated in more detail using longer time series in order to evaluate their impact in agricultural production.

Description: Broomcorn millet (Panicum miliaceum L.) is one of the earliest domesticated cereals worldwide, holding significant agricultural, historical, and evolutionary importance. However, our genomic knowledge of it is rather limited at present, hampering further genetic and evolutionary studies. Here, we sequenced and assembled the chloroplast genome (cp) of broomcorn millet and compared it with five other Panicoideae species. Results showed that the cp genome of broomcorn millet was 139,826 bp in size, with a typical quadripartite structure. In total, 108 genes were annotated and 18 genes were duplicated in the IR (inverted region) region, which was similar to other Panicoideae species. Comparative analysis showed a rather conserved genome structure between them, with three common regions. Furthermore, RNA editing, codon usage, and expansion of the IR, as well as simple sequence repeat (SSR) elements, were systematically investigated and 13 potential DNA markers were developed for Panicoideae species identification. Finally, phylogenetic analysis implied that broomcorn millet was a sister species to Panicum virgatum within the tribe Paniceae, and supported a monophyly of the Panicoideae. This study has reported for the first time the genome organization, gene content, and structural features of the chloroplast genome of broomcorn millet, which provides valuable information for genetic and evolutionary studies in the genus Panicum and beyond.

Description: Eloquent information about the genetic basis of inheritance is important for any breeding program. Therefore, a diallel study was conducted under the influence of tomato leaf curl virus (TLCV) disease, using the eleven advanced lines of tomato. Firstly, information regarding percent disease index (PDI) was determined via artificial screening with viruliferous whiteflies. Later, these lines were crossed in a half diallel mating design to produce fifty-five one-way hybrids. These hybrids and parental genotypes were evaluated for morphological and biochemical traits under open field conditions. Using the Griffing approach (Method II and Model I), the basis of the inheritance of traits was determined. Furthermore, a Bayesian model was applied to the total yield descriptor. Correlation data indicated that total yield was not correlated with any other trait. The significant general combining ability (GCA) and specific combining ability (SCA) values indicate exploitable genetic variation. The broad-sense heritability values were larger than narrow-sense heritability, showing that selection will be efficient for the improvement of these traits. Hybrid combinations H23, H42 and H49 can be considered efficient for the selection of multiple traits, including yield. Overall, this study provides useful information regarding the genetics of important traits of tomato under TLCV infestation.

Description: Nitrogen (N) rate increases used by many farmers produce a reduced or null effect on N recovery efficiency (RE) by crops. Therefore, management practices to reduce N losses and increase RE are necessary. Co-polymer maleic itaconic acid (NSN) have become available for use with urea and has shown potential in reducing N losses. The objective of this study was to evaluate the effectiveness of urea treated with NSN on grain yield and RE in a no-till corn. A field experiment was carried out at Balcarce, Argentina over three years, evaluated treatments were urea and urea + NSN at 120 N kg ha−1, and additional 0 N treatment was included. Urea + NSN was effective to reduce total ammonia volatilization losses, and the average of two years were 1.4 (1.1% to N applied) and 8.7 kg ha−1 (7.2% to N applied) for urea + NSN and urea, respectively. However, while grain yield and N grain removal were not affected by urea + NSN, the N rate significantly increased grain yield and N grain removal. Nitrogen recovery efficiency was not affected by urea + NSN, RE (average of three years) was 29.0% and 27.8% for urea and urea + NSN, respectively. In conclusion, there was no advantage of using urea treated with NSN in no-till corn overgrain yield, N grain removal, or RE.

Description: Maize is an important food staple in many countries, and is useful in animal feed and many industrial applications. Its productivity is highly sensitive to drought stress, which may occur at any period during its growth cycle. The objective of this work was to compare the water stress influence on the performance of different maize genotypes in critical vegetative stages. Four genotypes of maize (namely a single-cross hybrid (AG 9045), a double-cross hybrid (AG 9011), a triple-cross hybrid (AG 5011), and a variety (AL Bandeirante)) were subjected to a 10-day period without irrigation in the vegetative stages that determine the number of kernel rows and the plant’s ability to take up nutrients and water (V4, V6 and V8). The impact of low water availability was assessed by analyzing plant height, height of the first ear insertion, stem diameter, yield per plant, and number of rows per ear, evincing that the yield per plant was the most sensitive parameter in all the stages. With regard to the influence of the genotype, the single-cross hybrid was demonstrated to be the most resilient to water shortage.

Description: The challenge of maintaining sufficient food, feed, fiber, and forests, for a projected end of century population of between 9–10 billion in the context of a climate averaging 2–4 °C warmer, is a global imperative. However, climate change is likely to alter the geographic ranges and impacts for a variety of insect pests, plant pathogens, and weeds, and the consequences for managed systems, particularly agriculture, remain uncertain. That uncertainty is related, in part, to whether pest management practices (e.g., biological, chemical, cultural, etc.) can adapt to climate/CO2 induced changes in pest biology to minimize potential loss. The ongoing and projected changes in CO2, environment, managed plant systems, and pest interactions, necessitates an assessment of current management practices and, if warranted, development of viable alternative strategies to counter damage from invasive alien species and evolving native pest populations. We provide an overview of the interactions regarding pest biology and climate/CO2; assess these interactions currently using coffee as a case study; identify the potential vulnerabilities regarding future pest impacts; and discuss possible adaptive strategies, including early detection and rapid response via EDDMapS (Early Detection & Distribution Mapping System), and integrated pest management (IPM), as adaptive means to improve monitoring pest movements and minimizing biotic losses while improving the efficacy of pest control.

Description: Benzoxazinoids (BXs) are secondary metabolites present in many Poaceae including the major crops maize, wheat, and rye. In contrast to other potentially toxic secondary metabolites, BXs have not been targets of counter selection during breeding and the effect of BXs on insects, microbes, and neighbouring plants has been recognised. A broad knowledge about the mode of action and metabolisation in target organisms including herbivorous insects, aphids, and plants has been gathered in the last decades. BX biosynthesis has been elucidated on a molecular level in crop cereals. Recent advances, mainly made by investigations in maize, uncovered a significant diversity in the composition of BXs within one species. The pattern can be specific for single plant lines and dynamic changes triggered by biotic and abiotic stresses were observed. Single BXs might be toxic, repelling, attractive, and even growth-promoting for insects, depending on the particular species. BXs delivered into the soil influence plant and microbial communities. Furthermore, BXs can possibly be used as signalling molecules within the plant. In this review we intend to give an overview of the current data on the biosynthesis, structure, and function of BXs, beyond their characterisation as mere phytotoxins.

Description: Easy handling and low unit N cost make prilled urea (46-0-0) a popular fertilizer. While incomplete recovery of granular urea applications by turfgrass is documented, field evaluations of NH3 volatilization mitigation by coatings or bioinhibitor efficiency enhancements are limited. Meanwhile, NH3 emissions reduce air quality and contribute to nutrient loading of water resources. Our objectives were to quantify 3- and 6-d ammonia emission and 9-week turfgrass recovery of unincorporated granular fertilizer application to turfgrass. In 2014 and 2015, commercial urea-N fertilizers were broadcast over a mature Kentucky bluegrass (Poa pratensis L. ‘Midnight’) lawn at 43 kg ha−1. Treatments included conventional urea and three enhanced-efficiency fertilizers; a blended fertilizer with 25% of its urea-N supplanted by polymer- and polymer-/sulfur-coated prills, or two stabilized urea fertilizers both amended by N-(n-butyl) thiophosphoric triamide (NBPT) and dicyandiamide (DCD) inhibitors. Using a 51% ‘trapping-efficiency’ flux chamber system under the field conditions described, 23.1 or 33.5% of the conventional urea-N was lost as NH3 over the respective 3- or 6-d period following application. Alternatively, dual amendment by NBPT and DCD resulted in approximately 10.3 or 19.6% NH3-N loss over the respective 3- or 6-d periods, and greater fertilizer-N recovery by the turfgrass over the 9-week experiments.

Description: The majority of flowering-plant species can survive complete air-dryness in their seed and/or pollen. Relatively few species (‘resurrection plants’) express this desiccation tolerance in their foliage. Knowledge of the regulation of desiccation tolerance in resurrection plant foliage is reviewed. Elucidation of the regulatory mechanism in resurrection grasses may lead to identification of genes that can improve stress tolerance and yield of major crop species. Well-hydrated leaves of resurrection plants are desiccation-sensitive and the leaves become desiccation tolerant as they are drying. Such drought-induction of desiccation tolerance involves changes in gene-expression causing extensive changes in the complement of proteins and the transition to a highly-stable quiescent state lasting months to years. These changes in gene-expression are regulated by several interacting phytohormones, of which drought-induced abscisic acid (ABA) is particularly important in some species. Treatment with only ABA induces desiccation tolerance in vegetative tissue of Borya constricta Churchill. and Craterostigma plantagineum Hochstetter. but not in the resurrection grass Sporobolus stapfianus Gandoger. Suppression of drought-induced senescence is also important for survival of drying. Further research is needed on the triggering of the induction of desiccation tolerance, on the transition between phases of protein synthesis and on the role of the phytohormone, strigolactone and other potential xylem-messengers during drying and rehydration.

Description: Bananas are an important part of the diets of millions of people around the globe. Low P absorption and use efficiency significantly restrict banana yields. To further explore the molecular mechanisms of P regulation in banana plants, we used RNA sequencing-based transcriptomic analysis for banana plants subjected to Pi deficit stress for 60 days. We detected 1900 significantly differentially expressed genes (DEGs) in aboveground plant parts and 7398 DEGs in root parts under low P stress. Gene ontology (GO) classification analysis showed that 156,291 GO terms belonging to molecular functions, 53,114 GO terms belonging to cellular components, and 228,544 GO terms belonging to biological processes were enriched in the aboveground and root components. A number of DEGs involved in energy metabolism-related processes, signal transduction, control of rhizosphere P activation, and Pi mobilization were found, which were confirmed by quantitative reverse-transcription Polymerase Chain Reaction (qRT-PCR) analysis. At the transcriptomic level, we detected 13 DEGs from different organs and with different functions in the time-course response to phosphorus deficiency stress. These DEGs may include some key genes that regulate the phosphorus network, increasing our understanding of the molecular mechanism of Pi homeostasis in banana. These findings will also help develop biotechnologies to create a variant of banana with more effective Pi absorption and utilization.

Description: Plants are exposed to numerous pathogens and fend off many of these with different phytohormone signalling pathways. Much is known about defence signalling in the dicotyledonous model plant Arabidopsisthaliana, but it is unclear to which extent knowledge from model systems can be transferred to monocotyledonous plants, including cereal crops. Here, we investigated the defence-inducing potential of Arabidopsis resistance-inducing compounds in the cereal crop barley. Salicylic acid (SA), folic acid (Fol), and azelaic acid (AzA), each inducing defence against (hemi-)biotrophic pathogens in Arabidopsis, were applied to barley leaves and the treated and systemic leaves were subsequently inoculated with Xanthomonastranslucens pv. cerealis (Xtc), Blumeria graminis f. sp. hordei (powdery mildew, Bgh), or Pyrenophora teres. Fol and SA reduced Bgh propagation locally and/or systemically, whereas Fol enhanced Xtc growth in barley. AzA reduced Bgh propagation systemically and enhanced Xtc growth locally. Neither SA, Fol, nor AzA influenced lesion sizes caused by the necrotrophic fungus P. teres, suggesting that the tested compounds exclusively affected growth of (hemi-)biotrophic pathogens in barley. In addition to SA, Fol and AzA might thus act as resistance-inducing compounds in barley against Bgh, although adverse effects on the growth of pathogenic bacteria, such as Xtc, are possible.

Description: Rapeseed (Brassica napus L.) with substantial lipid and oleic acid content is of great interest to rapeseed breeders. Overexpression of Glycine max transcription factors Dof4 and Dof11 increased lipid accumulation in Arabidopsis and microalgae, in addition to modifying the quantity of certain fatty acid components. Here, we report the involvement of GmDof4 and GmDof11 in regulating fatty acid composition in rapeseeds. Overexpression of GmDof4 and GmDof11 in rapeseed increased oleic acid content and reduced linoleic acid and linolenic acid. Both qPCR and the yeast one-hybrid assay indicated that GmDof4 activated the expression of FAB2 by directly binding to the cis-DNA element on its promoters, while GmDof11 directly inhibited the expression of FAD2. Thus, GmDof4 and GmDof11 might modify the oleic acid content in rapeseed by directly regulating the genes that are associated with fatty acid biosynthesis.

Description: In wild habitats, fruit dehiscence is a critical strategy for seed dispersal; however, in cultivated crops it is one of the major sources of yield loss. Therefore, indehiscence of fruits, pods, etc., was likely to be one of the first traits strongly selected in crop domestication. Even with the historical selection against dehiscence in early domesticates, it is a trait still targeted in many breeding programs, particularly in minor or underutilized crops. Here, we review dehiscence in pulse (grain legume) crops, which are of growing importance as a source of protein in human and livestock diets, and which have received less attention than cereal crops and the model plant Arabidopsis thaliana. We specifically focus on the (i) history of indehiscence in domestication across legumes, (ii) structures and the mechanisms involved in shattering, (iii) the molecular pathways underlying this important trait, (iv) an overview of the extent of crop losses due to shattering, and the effects of environmental factors on shattering, and, (v) efforts to reduce shattering in crops. While our focus is mainly pulse crops, we also included comparisons to crucifers and cereals because there is extensive research on shattering in these taxa.

Description: Future challenges to the role of durum and bread wheat in global food security will be shaped by their potential to produce larger yields and better nutritional quality, while increasingly adapting to multiple biotic and abiotic stresses in the view of global climate change. There is a dearth of information on comparative assessment of phenotypic plasticity in both wheat species under long-term multiple abiotic stresses. Phenotypic plasticities of two durum and bread wheat genotypes were assessed under increasing abiotic and edaphic stresses for six years. Combinations of normal and reduced length of growing season and population density, with or without rotation, generated increasing levels of competition for resources and impacted phenotypic plasticity of several plant and yield attributes, including protein and micronutrients contents. All the phenotypic plasticity (PPs) estimates, except for the C:N ratio in both genotypes and grain protein content in T. aestivum genotype, were impacted by abiotic stresses during the second stress phase (PS II) compared with the first (PS I); whereas, covariate effects were limited to a few PPs (e.g., biomass, population density, fertile tillers, grain yield, and grain protein content). Discrimination between factor levels decreased from abiotic phases 〉 growth stages 〉 stress treatments and provided selection criteria of trait combinations that can be positively resilient under abiotic stress (e.g., spike harvest and fertility indices combined with biomass and grain yield in both genotypes). Validation and confirmatory factor models and multiway cluster analyses revealed major differences in phenotypic plasticities between wheat genotypes that can be attributed to differences in ploidy level, length of domestication history, or constitutive differences in resources allocation. Discriminant analyses helped to identify genotypic differences or similarities in the level of trait decoupling in relation to the strength of their correlation and heritability estimates. This information is useful in targeted improvement of traits directly contributing to micronutrient densities, yield components, and yield. New wheat ideotype(s) can be designed for larger grain yield potential under abiotic stress by manipulating yield components that affect kernels m−2 (e.g., number of tillers, number of florets per spikelet, and eventually spike fertility and harvest indices) without impacting nutrient densities and kernel weight, thus raising harvest index beyond its current maximum.

Description: Tomato (Solanum lycopersicum L.) is probably the most important vegetable consumed around the world, and like other produce is affected by stresses and diseases that reduce the yield and production. The purpose of this work was to study the phytobiome of the tomato seeds of two hybrids in order to understand first of all whether tomato cultivars host similar groups of organisms, as well as their effect on the community structure, particularly of those microbes with the potential to promote growth and/or control plant pathogens. Different cultivars of tomato (genotypes) host significantly different endophytic communities, which is also reflected at the order level. These communities are particularly rich in spore-forming bacteria that have the ability either to promote plant growth or synthetize antimicrobial compounds that deter plant pathogens. We conclude that the seeds of the tomato cultivars Elpida and Silverio are sources of endophytic bacteria capable of synthetizing antifungal substances that could potentially be used for biocontrol against plant-pathogenic fungi.

Description: The breeding of stress-tolerant cultivated plants that would allow for a reduction in harvest losses and undesirable decrease in quality attributes requires a new quality of knowledge on molecular markers associated with relevant agronomic traits, on quantitative metabolic responses of plants to stress challenges, and on the mechanisms controlling the biosynthesis of these molecules. By combining metabolomics with genomics, transcriptomics and proteomics datasets a more comprehensive knowledge of the composition of crop plants used for food or animal feed is possible. In order to optimize crop trait developments, to enhance crop yields and quality, as well as to guarantee nutritional and health factors that provide the possibility to create functional food or feedstuffs, knowledge about the plants’ metabolome is crucial. Next to classical metabolomics studies, this review focuses on several metabolomics-based working techniques, such as sensomics, lipidomics, hormonomics and phytometabolomics, which were used to characterize metabolome alterations during abiotic and biotic stress in order to find resistant food crops with a preferred quality or at least to produce functional food crops.

Description: Industrial wastes and agricultural byproducts are increasingly used in crop production as fertilizers, but their impacts on soil carbon (C) sequestration remain poorly understood. The aim of this study was to examine the effects of applying steel slag (SS), biochar (B), and a combination of these two materials (SS + B) on total soil organic C (SOC), active SOC fractions, and C pool management index (CPMI) in a subtropical paddy field in China. The treatments were applied at a rate of 8 t ha−1 to rice at the two (early and late) crop seasons in 2015. The SOC concentrations in the top 30 cm soils in the SS + B treatments were 28.7% and 42.2% higher in the early and late crops, respectively, as compared to the controls (p 〈 0.05). SOC was positively correlated with soil C:N ratio across the two crop seasons (r = 0.92–0.97, p 〈 0.01). As compared to the control, SS + B treatment had significantly higher carbon pool index (CPI) in both early (22.4%) and late (40.1%) crops. In the early crop, the C pool activity index (CPAI) was significantly lower in B and SS + B treatments by over 50% than in the control, while the soil C pool management index (CPMI) in the SS, B, and SS + B treatments was lower than that in the control by 36.7%, 41.6%, and 45.4%, respectively. In contrast, in the late crop, no significant differences in CPAI and CPMI were observed among the treatments. Our findings suggest that the addition of steel slag and biochar in subtropical paddy fields could decrease active SOC pools and enhance soil C sequestration only in the early crop, but not the late crop.

Description: Drought and phosphorus deficiency in the soil are the major production limitations of common beans (Phaseolus vulgaris L.) in Sub-Saharan Africa. This study measured the yield responses of low phosphorus-tolerant common beans to drought stress. A field experiment was conducted under two drought conditions codenamed, non-drought-stress (NDS) and drought-stress (DS). The former was located at Mukono Zonal Agricultural Research and Development Institute (MUZARDI) in Mukono District, characterised by rainfall of more than 400 mm season−1. The latter was situated at Wabinyonyi in Nakasongola District, characterised by less than 300 mm season−1; both in central Uganda. Treatments included the two study conditions (NDS and DS); and four test bean genotypes, AFR703-1, AFR 708, JESCA, and MCM 2001, against a local check, K131. A water deficit of 156 mm season−1 was observed in the DS site causing a drought intensity index (DII) of 40%. That pattern contrasted considerably in the NDS site where the actual rainfall did not significantly (p 〉 0.05) vary from the required water by the bean plant. Whereas genotypes AFR703-1 and AFR708 out-yielded the local check in NDS by 213 and 681 kg ha−1, respectively; their grain yield harvested was comparable to the control yield in DS. When grown under DS, low P-tolerant beans, especially the AFR703-1 and AFR708, survived drought stress through faster development by reducing the number of days to flower, reach physiological maturity and develop seeds. AFR703-1 and AFR708 sufficiently withstand drought stress, and are therefore recommended for inclusion in cropping systems that are characteristically constrained by the combined soils’ P deficiency and/or drought.

Description: Active crop canopy sensors can be used for non-destructive real-time diagnosis of crop nitrogen (N) status and guiding in-season N management. However, limited studies have compared the performances of two commercially available sensors with three different wavebands: Crop Circle ACS-470 (CC-470) and Crop Circle ACS-430 (CC-430). The objective of this study was to evaluate the performances of CC-470 and CC-430 sensors for estimating winter wheat (Triticum aestivum L.) N status at different measurement heights (40 cm, 70 cm and 100 cm) and growth stages. Results indicated that the canopy reflectance values of CC-470 were more affected by height compared to the CC-430 sensor. The normalized difference red edge (NDRE) and red edge chlorophyll index (CIRE) of CC-430 were stable at the three different measuring heights. The relationships between these indices and the N status indicators were stronger at the Feekes 9–10 stages than the Feekes 6–7 stages for both sensors; however, the CC-430 sensor-based vegetation indices had higher coefficient of determination (R2) values for both stages. It is concluded that the CC-430 sensor is more reliable than CC-470 for winter wheat N status estimation due to its capability of making height-independent measurements. These results demonstrated the importance of considering the influences of height when using active canopy sensors in field measurements.

Description: To improve sustainability of agriculture, high yielding crop varieties with improved water use efficiency (WUE) are needed. Despite the feasibility of assessing WUE using different measurement techniques, breeding for WUE and high yield is a major challenge. Factors influencing the trait under field conditions are complex, including different scenarios of water availability. Plants with C3 photosynthesis are able to moderately increase WUE by restricting transpiration, resulting in higher intrinsic WUE (iWUE) at the leaf level. However, reduced CO2 uptake negatively influences photosynthesis and possibly growth and yield as well. The negative correlation of growth and WUE could be partly disconnected in model plant species with implications for crops. In this paper, we discuss recent insights obtained for Arabidopsis thaliana (L.) and the potential to translate the findings to C3 and C4 crops. Our data on Zea mays (L.) lines subjected to progressive drought show that there is potential for improvements in WUE of the maize line B73 at the whole plant level (WUEplant). However, changes in iWUE of B73 and Arabidopsis reduced the assimilation rate relatively more in maize. The trade-off observed in the C4 crop possibly limits the effectiveness of approaches aimed at improving iWUE but not necessarily efforts to improve WUEplant.