ALBERT

Description: Meristems are central to plant growth and development, yet evidence of directly manipulating this control to improve crop yield is scarce. Kernel row number (KRN) is an important agronomic trait that can directly affect maize (Zea mays L.) yield. However, this trait is difficult to select by phenotyping, since it is highly variable in the mixed genetic backgrounds in early selfing generations. This study sought to improve this trait by marker-assisted backcrossing (MABC) of a weak allele of FASCIATED EAR 2 that is known to affect inflorescence meristem size, but the effect of which on yield is unclear. All of the four introgressed tropical elite inbreds of different heterotic groups, which are homozygous for the fea2-1328 allele, had 2–5 more KRNs compared to their respective recurrent parents. Furthermore, one hybrid made from crosses between two introgressed parents also had KRN increases that resulted in up to 28% yield increase compared to the original hybrid across multiple yield trials. The novel negative effects of the pericentromeric fea2 and/or its linkage drag effect on plant height, seed weight, and ear length, which could prevent line improvement, were revealed in several genetic backgrounds. Integration of conventional phenotypic selection to overcome these undesirable effects was discussed. This is the first work to demonstrate the possibility to increase yield of maize varieties using a mutation in a meristem size regulator. The crossing, selection strategies, and recombinant lines in this work can be applied to other elite maize hybrids and provide a potentially straightforward, non-transgenic way to improve the yield of an existing variety by 8–28%.

Description: Difficulties in breeding new rice cultivars that have a high yield, are acceptable quality, and are tolerant to environmental stresses have been the major constraint of rice production in many developing countries, as these traits are determined by multiple genes associated with complicated and uncontrollable gene segregations.Furthermore, the gene/QTL (quantitative trait locus) introduced to the cultivar is unstable due to the interaction among the active genes, which determine the phenotypic performance, not yet been well understood or controllable. In this study, the N-methyl-N-nitrosourea (MNU)-induced mutation was applied to the heterozygote of the F1 generation from the cross between TBR1 (female) and KD18 (male parent). The phenotype and genotype of the M2 and M3 generations were evaluated and showed that the mutant population phenotypes, including the plant height, semi-dwarfism, amylose content, protein content, gel consistency, grain yield, and spikelet fertility, varied. Interestingly, no segregation among the genotypes in the M2 and M3 generations was observed, while the genotypes of the control population were either paternally inherited or indeterminable when using 28 polymorphism simple sequence repeat (SSR) markers that were identified on parental lines from 200 markers. The MNU-induced mutation caused maternal inheritance in the segregating populations, as primarily important agronomic traits were maternally succeeded from the female line TBR1. The findings of this study indicated that, through the use of MNU, the breeding of rice cultivars with close genetic backgrounds (similarity coefficient = 0.52) could be shortened by the maternal control of important qualities, such as pest and disease resistance and high yield, thus contributing to sustainable rice production for rice farmers. Further examination of rice cultivars with a greater difference in the genetic background should be subsequently conducted.

Description: Mutation technology has been applied more in recent decades to achieve novel products that are not commonly found in nature. An experiment was conducted to examine the effects of an N-methyl-N-nitrosourea (MNU) mutation on the growth, yield, and physicochemical properties of rice. Seeds of two rice cultivars (K1: DT84, and K3: Q5), along with their mutant lines (K2: mutated DT84, and K4: mutated Q5), were sown, and the established seedlings were transplanted to an open field. Ten hills per plot were randomly selected to evaluate growth parameters, yield, and components. Physicochemical attributes, including protein, amylose, and lipid contents, as well as taste score were measured by a quality tester device. The results showed that plant length, tiller number, and panicle length were higher in mutant lines than those of their cultivars. Furthermore, mutant lines took longer to reach heading and maturity stage. The highest panicle number, spikelet number, repined ratio, 1000 grain weight, 1000 brown rice weight, and grain yield were obtained in mutant lines, as compared to cultivars. The greatest grain yield was obtained in the K4 mutant line (11.6 t/ha), while the lowest was recorded in the K1 cultivar (7.7 t/ha). Lower amylose, protein, and lipid contents were observed in mutant lines compared to those in cultivars. The taste score, which increased from 67.7 to 73.7, was found to be correlated with lower amylose, protein, and lipid contents. The mutation approach increased the grain length but decreased the grain width of tested varieties. This study highlights and suggests the importance of MNU mutation in terms of rice yield improvement with preferable quality.

Description: Methadone maintenance treatment (MMT) has been scaled up significantly in recent years. This study aimed to investigate the pattern of polysubstance use in 395 MMT patients and its contextualized associated factors. A cross-sectional study was performed in three outpatient MMT clinics in Nam Dinh Province. Multivariate Poisson regression was used to identify factors associated with polysubstance use status. The mean MMT duration and the current MMT dose was 3.3 years and 69.2 mg, respectively. Among participants, 24.8% reported daily alcohol use, 68.6% smoked regularly, and 6% used illicit drugs. Peer pressure and MMT suboptimal adherence were found to associate with continual usage of drugs (47.8%). Participants who lived with a spouse/partner, were self-employed, and smoked were more likely to drink alcohol. Those who drink were also more likely to smoke, and vice versa. Recommendations for policymakers include community-based education and promotional programs aiming to decrease substance usage in the community as well as encouraging and supporting the private health sector in establishing private MMT services and clinics. Further longitudinal studies on polysubstance usage among MMT patients should also be conducted.

Description: Momilactones A (MA) and B (MB) are the active phytoalexins and allelochemicals in rice. In this study, MA and MB were purified from rice husk of Oryza sativa cv. Koshihikari by column chromatography, and purification was confirmed by high-performance liquid chromatography, thin-layer chromatography, gas chromatography-mass spectrometry, liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS), and 1H and 13C nuclear magnetic resonance analyses. By in vitro assays, both MA and MB exerted potent inhibition on α-amylase and α-glucosidase activities. The inhibitory effect of MB on these two key enzymes was greater than that of MA. Both MA and MB exerted greater α-glucosidase suppression as compared to that of the commercial diabetic inhibitor acarbose. Quantities of MA and MB in rice grain were 2.07 ± 0.01 and 1.06 ± 0.01 µg/dry weight (DW), respectively. This study was the first to confirm the presence of MA and MB in refined rice grain and reported the α-amylase and α-glucosidase inhibitory activity of the two compounds. The improved protocol of LC-ESI-MS in this research was simple and effective to detect and isolate MA and MB in rice organs.

Description: Although many investigations on phytochemicals in rice plant parts and root exudates have been conducted, information on the chemical profile of essential oil (EO) and potent biological activities has been limited. In this study, chemical compositions of rice leaf EO and in vitro biological activities were investigated. From 1.5 kg of fresh rice leaves, an amount of 20 mg EO was obtained by distillation and analyzed by gas chromatography-mass spectrometry (GC-MS), electrospray ionization (ESI), and atmospheric pressure chemical ionization (APCI) to reveal the presence of twelve volatile constituents, of which methyl ricinoleate (27.86%) was the principal compound, followed by palmitic acid (17.34%), and linolenic acid (11.16%), while 2-pentadecanone was the least (2.13%). Two phytoalexin momilactones A and B were first time identified in EO using ultra-performance liquid chromatography coupled with electrospray mass spectrometry (UPLC/ESI-MS) (9.80 and 4.93 ng/g fresh weight, respectively), which accounted for 7.35% and 3.70% of the EO, respectively. The assays of DPPH (IC50 = 73.1 µg/mL), ABTS (IC50 = 198.3 µg/mL), FRAP (IC50 = 700.8 µg/mL) and β-carotene oxidation (LPI = 79%) revealed that EO possessed an excellent antioxidant activity. The xanthine oxidase assay indicated that the anti-hyperuricemia potential was in a moderate level (IC50 = 526 µg/mL) as compared with the standard allopurinol. The EO exerted potent inhibition on growth of Raphanus sativus, Lactuca sativa, and two noxious weeds Echinochloa crus-galli, and Bidens pilosa, but in contrast, the growth of rice seedlings was promoted. Among the examined plants, the growth of the E. crus-galli root was the most inhibited, proposing that constituents found in EO may have potential for the control of the problematic paddy weed E. crus-galli. It was found that the EO of rice leaves contained rich phytochemicals, which were potent in antioxidants and gout treatment, as well as weed management. Findings of this study highlighted the potential value of rice leaves, which may provide extra benefits for rice farmers.

Description: Mutation technology has been applied more in recent decades to achieve novel products that are not commonly found in nature. An experiment was conducted to examine the effects of an N-methyl-N-nitrosourea (MNU) mutation on the growth, yield, and physicochemical properties of rice. Seeds of two rice cultivars (K1: DT84, and K3: Q5), along with their mutant lines (K2: mutated DT84, and K4: mutated Q5), were sown, and the established seedlings were transplanted to an open field. Ten hills per plot were randomly selected to evaluate growth parameters, yield, and components. Physicochemical attributes, including protein, amylose, and lipid contents, as well as taste score were measured by a quality tester device. The results showed that plant length, tiller number, and panicle length were higher in mutant lines than those of their cultivars. Furthermore, mutant lines took longer to reach heading and maturity stage. The highest panicle number, spikelet number, repined ratio, 1000 grain weight, 1000 brown rice weight, and grain yield were obtained in mutant lines, as compared to cultivars. The greatest grain yield was obtained in the K4 mutant line (11.6 t/ha), while the lowest was recorded in the K1 cultivar (7.7 t/ha). Lower amylose, protein, and lipid contents were observed in mutant lines compared to those in cultivars. The taste score, which increased from 67.7 to 73.7, was found to be correlated with lower amylose, protein, and lipid contents. The mutation approach increased the grain length but decreased the grain width of tested varieties. This study highlights and suggests the importance of MNU mutation in terms of rice yield improvement with preferable quality.

Description: Methadone maintenance treatment (MMT) has been scaled up significantly in recent years. This study aimed to investigate the pattern of polysubstance use in 395 MMT patients and its contextualized associated factors. A cross-sectional study was performed in three outpatient MMT clinics in Nam Dinh Province. Multivariate Poisson regression was used to identify factors associated with polysubstance use status. The mean MMT duration and the current MMT dose was 3.3 years and 69.2 mg, respectively. Among participants, 24.8% reported daily alcohol use, 68.6% smoked regularly, and 6% used illicit drugs. Peer pressure and MMT suboptimal adherence were found to associate with continual usage of drugs (47.8%). Participants who lived with a spouse/partner, were self-employed, and smoked were more likely to drink alcohol. Those who drink were also more likely to smoke, and vice versa. Recommendations for policymakers include community-based education and promotional programs aiming to decrease substance usage in the community as well as encouraging and supporting the private health sector in establishing private MMT services and clinics. Further longitudinal studies on polysubstance usage among MMT patients should also be conducted.

Description: Attempts regarding the improvement and development of novel rice with better quality and higher productivity have been increasing. Among approaches, mutation is a direct alteration on the genome and considered as one of the most beneficial routes to acquire new beneficial traits in rice. An experiment was carried out to explore the effects of N-methyl-N-nitrosourea (MNU) mutation on the antioxidant activities, phytochemical compounds, and momilactones A (MA) and B (MB) in rice. Two rice cultivars, K1 (an original cultivar DT84) and K2 (mutated DT84), were examined. Antioxidant activities, phenolic compounds, and momilactones of the rice grain, husk, and straw portions were measured and quantified. Antioxidant activities were higher in grain and straw of K2, whereas K1 showed greater antioxidant activity in rice husk. Additionally, K2 displayed higher total phenolic contents (TPC) in grain and straw as well as lower of it in the husk, but these variations significantly differed only in the straw portion. An increase in total flavonoid contents (TFC) was observed in the husk of K1, while K2 significantly enhanced TFC in straw. Both MA and MB, two compounds obtaining antidiabetes, anticancer, antimicrobial, antigout, and antiobesity properties, were detected and quantified in grain, husk, and straw of K1 and K2 samples. Generally, the contents of MA were higher than MB in all tested portions of rice crop. MA and MB were higher in straw followed by those in husk and grain, respectively. K2 contained higher amounts of MA and MB in straw and husk, but lower contents in grain compared with those in K1. This study illustrates that MNU mutation can improve grain quality and enhance bioactive compounds in straw, husk, and grain of rice. This approach has the potential to develop functional foods from rice, and therefore help farmers in developing countries to improve value in rice production.

Description: Difficulties in breeding new rice cultivars that have a high yield, are acceptable quality, and are tolerant to environmental stresses have been the major constraint of rice production in many developing countries, as these traits are determined by multiple genes associated with complicated and uncontrollable gene segregations.Furthermore, the gene/QTL (quantitative trait locus) introduced to the cultivar is unstable due to the interaction among the active genes, which determine the phenotypic performance, not yet been well understood or controllable. In this study, the N-methyl-N-nitrosourea (MNU)-induced mutation was applied to the heterozygote of the F1 generation from the cross between TBR1 (female) and KD18 (male parent). The phenotype and genotype of the M2 and M3 generations were evaluated and showed that the mutant population phenotypes, including the plant height, semi-dwarfism, amylose content, protein content, gel consistency, grain yield, and spikelet fertility, varied. Interestingly, no segregation among the genotypes in the M2 and M3 generations was observed, while the genotypes of the control population were either paternally inherited or indeterminable when using 28 polymorphism simple sequence repeat (SSR) markers that were identified on parental lines from 200 markers. The MNU-induced mutation caused maternal inheritance in the segregating populations, as primarily important agronomic traits were maternally succeeded from the female line TBR1. The findings of this study indicated that, through the use of MNU, the breeding of rice cultivars with close genetic backgrounds (similarity coefficient = 0.52) could be shortened by the maternal control of important qualities, such as pest and disease resistance and high yield, thus contributing to sustainable rice production for rice farmers. Further examination of rice cultivars with a greater difference in the genetic background should be subsequently conducted.