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  • wheat  (53)
  • Springer  (53)
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  • 1995-1999  (53)
  • 1997  (53)
  • 1
    ISSN: 1572-9699
    Keywords: bioluminescence ; Pseudomonas ; root colonization ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The bioluminescently marked Pseudomonas fluorescens strain 5RL, has been used previously to follow colonisation of soy bean roots (De Weger et al. [1991] Appl. Environ. Microbiol. 57:36-41). In the present paper the method has been further developed and optimized for wheat roots and it is used to get a quick overview of the colonisation patterns of many different root systems at the same time. Colonisation was followed on wheat plants grown in our gnotobiotic sand system (Simons et al., 1996. Mol Plant Microbe Interact 9: 600–607) and the following results were obtained. (i) A spatio-temporal analysis of the colonisation of wheat roots showed that 4 days after planting the highest bacterial activity was observed at the upper part of the root. After 6 days the high bacterial activity at the upper part was further increased, whereas spot-like activities were observed on the lower root parts, possibly due to micro-colonies. (ii) Bacterial mutations causing lack of motility or auxotrophy for amino acids resulted in impaired colonisation of the lower root parts, indicating that motility and prototrophy for the involved amino acid(s) are important factors for wheat root colonisation by strain 5RL. (iii) Coinoculation of strain 5RL with other wild type Pseudomonas strains on the root influenced the colonisation pattern observed for strain 5RL. Colonisation was not visually affected when the competing strain was a poor root coloniser, but was severely reduced when the competing strain was a good root coloniser. The results show that the spatio-temporal colonisation of wheat root by P. fluorescens strain 5RL and derivatives is similar to that of strain WCS365 on tomato. The advantage of the use of lux-marked strains is that the results are obtained much quicker than when conventional methods are used and that the result is supplied as an image of the colonisation pattern of many different roots.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 23 (1997), S. 2695-2705 
    ISSN: 1573-1561
    Keywords: Defense ; herbivory ; aphids ; wheat ; Gramineae ; hydroxamic acids ; Defense theory ; Carbon/Nutrient theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Hydroxamic acids (Hx) are natural products of Gramineae that are associated with cereal resistance to pests. We aimed at characterizing the induction of Hx accumulation in seedlings of wheat,Triticum aestivum, by short-term infestation of the cereal aphid,Rhopalosiphum padi. A load of 25 aphids increased significantly the Hx levels in the infested primary leaf in comparison with control levels. Lower loads did not increase Hx concentration. Aphid infestation lasting 16 hr did not elicit induction of Hx, even after a time-lag of 32 hr to allow the expression of any induced response. Forty-eight hours was the minimum duration of aphid infestation required to trigger Hx induction. The age of the infested tissue (the primary leaf) did not affect induction. Similar increases of Hx were found in unfolding, expanding, and totally expanded primary leaves. It was determined that the regime of nutrient supply (N-intensive nutritive solutions at low and high concentration) to wheat seedlings had no effect on the magnitude of the aphid-induced Hx (N-based secondary metabolites). Results obtained are discussed in the framework of general theories of plant defense allocation.
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  • 3
    ISSN: 1573-5028
    Keywords: ADP-glucose pyrophosphorylase ; anther ; pollen ; male sterility ; water stress ; wheat ; starch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In wheat (Triticum aestivum L.), water deficit during meiosis in the microspore mother cells (MMCs) induces pollen abortion, resulting in the failure of fertilization and a reduction in grain set. In stressed plants, meiosis in MMCs proceeds normally but subsequent pollen development is arrested. Unlike normal pollen grains, which accumulate starch during the late maturation phase, stress-affected anthers contain pollen grains with little or no starch. Stress also alters the normal distribution of starch in the anther wall and connective tissue. To determine how starch biosynthesis is regulated within the developing anthers of stressed plants, we studied the expression of ADP-glucose pyrophosphorylase (AGP), which catalyzes the rate limiting step of starch biosynthesis. Two partial-length cDNAs corresponding to the large subunit of AGP were amplified by RT-PCR from anther RNA, and used as probes to monitor AGP expression in developing anthers of normal and water-stressed plants. These clones, WAL1 and WAL2, had identical deduced amino acid sequences and shared 96% sequence identity at the nucleic acid level. In normal anthers, AGP expression was biphasic, indicating that AGP expression is required for starch biosynthesis both during meiosis and later during pollen maturation. AGP expression in stressed anthers was not affected during the first phase of starch accumulation, but was strongly inhibited during the second phase. We conclude from these results that the reduced starch deposition later in the development of stressed pollen could be the result of a lower expression of AGP. However, this inhibition of AGP expression is unlikely to be the primary cause of male sterility because anatomical symptoms of pollen abortion are observed prior to the time when AGP expression is inhibited.
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  • 4
    ISSN: 1573-5028
    Keywords: chloroplast ; in vitro transcription ; light ; psbA ; psbD/C operon ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dynamical aspects of three chloroplast promoters responding to change in light condition were examined in mature chloroplasts of wheat (Triticum aestivum) by in vitro transcription. The wheat psbD/C operon has four distinct promoters, two of which named as D/C-3 and D/C-4 promoters dominantly function in mature chloroplasts to produce the mRNAs encoding D2/CP43 and CP43 alone, respectively. Activity of the D/C-3 promoter in mature chloroplasts was reduced to less than 30% by 24 h dark adaptation and recovered by re-illumination to the original level within 30 to 60 min. The activation of the D/C-3 promoter which requires de novo cytoplasmic protein synthesis was induced by low fluence of light (e.g. 16 µE m-2 s-1), but the extent of activation increased with increasing light fluence. The accumulation of mRNAs from the D/C-3 promoter saturated at 2- to 3-fold higher level within 2 h when the dark-adapted seedlings were transferred to the lig at 72 µE m-2 s-1, concomitant with the increase in rate of D2 synthesis, suggesting that synthesis of D2 in mature chloroplasts is controlled via the D/C-3 promoter activity in a light-dependent way. Activity of the D/C-4 promoter slightly increased in the dark and decreased in the light. Effect of light on the psbA promoter activity was not observed at all in mature chloroplasts. In vitro transcriptional analysis of the D/C-3 promoter with 5′ deletion mutations revealed that at least two cis elements which are located within the sequences of -78 to -47 and -46 to -29 of the transcription initiation site, respectively, act as enhancing elements in the D/C-3 promoter. The light-switching element of the transcription, however, was suggested to be located in the core promoter sequence downstream of the -35 element.
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  • 5
    ISSN: 1573-5028
    Keywords: cold temperature ; dehydration ; greening ; protein kinase ; Triticum aestivum/ ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have identified a new wheat PKABA1/-like protein kinase gene, TaPK3/, that is expressed in greening wheat seedlings. TaPK3 has high sequence homology (97% similarity with some sequence diversity at the 3' end) to the wheat PKABA1 protein kinase mRNA, which is upregulated by cold-temperature treatment, dehydration and abscisic acid (ABA). Use of a TaPK3 gene-specific probe has revealed that TaPK3 is differentially expressed with respect to PKABA1. TaPK3 mRNA accumulates in greening shoot tissue of wheat, but is not affected by dehydration, cold-temperature treatment or ABA. Based on sequence and expression differences, we conclude that expression of the PKABA1/-like protein kinases is not limited to stress responses.
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  • 6
    Electronic Resource
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    Plant molecular biology 34 (1997), S. 643-650 
    ISSN: 1573-5028
    Keywords: callus ; crown tissue ; gene expression ; low temperature ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The low-temperature (2 °C)-specific wheat cDNA, pTACR7, represents a gene designated tacr7 from hard red winter wheat (HRWW; Triticum aestivum L. cv. Winoka). The term low-temperature-specific (LTS) is used because tacr7 is not induced by ABA or stresses such as salt, dehydration, and heat. pTACR7 was isolated by RT-PCR with mRNA from wheat crown tissue, the oligonucleotide primers derived from the barley cognate pHVCR8 (GenBank accession number L28091). Based on the deduced amino acid sequence, TACR7 is highly hydrophobic, with a single transmembrane domain and an amino acid bias for leucine (19%). Thus, the encoded protein TACR7 is unique among low-temperature-regulated wheat proteins described in the literature. Analysis of steady-state levels of tacr7 transcripts (630 nt) showed accumulation in wheat seedlings, crown tissue, and callus cultures after transfer from control (25 °C) to low temperature (2 °C). No detectable transcripts were observed by northern blot hybridization with pTACR7 probe from seedling or callus treated with ABA, salt, dehydration, or heat stress. tacr7 transcripts accumulated during 2 °C exposure to a greater amount in a freeze-resistant HRWW (FR; SDmut 16029) than in a freeze-susceptible HRWW (FS; SDmut 16169) crown tissue, with the largest difference between genotypes being 30% ± 3% at 3 weeks.
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  • 7
    ISSN: 1572-9788
    Keywords: leaf rust ; molecular marker ; receptor-like kinase ; resistance breeding ; resistance gene ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We recently showed that the Lr10 wheat leaf rust resistance gene cosegregated with the candidate resistance gene Lrk10 which encodes a putative receptor-like kinase. The aim of this study was to develop Lrk10-derived molecular markers for the detection of the Lr10 gene in breeding material. Different subfragments of Lrk10 were tested as RFLP markers for the Lr10 resistance gene. The most specific fragment (Lrk10-6) was converted into the PCR-based STS marker STSLrk10-6. Both the RFLP and the STS marker did not give a signal with near isogenic lines containing a different Lr gene. The applicability of these markers for the detection of Lr10 in genetically diverse material was tested with 62 wheat and spelt breeding lines, mostly from European breeding programmes. Twelve varieties known to have Lr10 showed the same alleles as the originally characterized line ThatcherLr10. Most of the lines with unknown composition at the Lr10 locus had a null allele with both the RFLP marker Lrk10-6 and the marker STSLrk10-6 whereas 20% of the lines had a different allele. For six lines, including a traditional spelt variety derived from a landrace, both markers showed the same allele as Thatcher Lr10. Artificial infections of these lines with an isolate avirulent on Lr10 resulted in a hypersensitive reaction of all these lines, indicating also the presence of the Lr10 resistance gene. These data demonstrate that the markers derived from sequences of Lrk10 are highly specific for the Lr10 gene in breeding material of very diverse genetic origin. The markers will allow the defined deployment of Lr10 in wheat breeding programmes and will contribute to the elucidation of the role of Lr10 in polygenic resistances against leaf rust.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Molecular breeding 3 (1997), S. 177-181 
    ISSN: 1572-9788
    Keywords: bulked segregant analysis ; H21 ; near-isogenic lines (NILs) ; RAPD ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Near-isogenic lines in conjunction with bulked segregant analysis were used to identify a DNA marker in wheat (Triticum aestivum L.) associated with the H21 gene conferring resistance to biotype L of Hessian fly [Mayetiola destructor (Say)] larvae. Near-isogenic lines were developed by backcross introgression BC3F3:4 (‘Coker 797’ * 4 / ‘Hamlet’) and differed by the presence or absence of H21 (on 2RL) derived from ‘Chaupon’ rye (Secale cereale L.). Bulked DNA samples were prepared from near-isogenic lines and BC3F2 population individuals segregating for reaction to Hessian fly biotype L and screened for random amplified polymorphic DNA markers using 46 10mer primers. Random-amplified polymorphic DNA markers from resistant and susceptible individuals and parental lines were scored and these data were used to identify a 3 kb DNA fragment that was related to the occurrence of H21. This fragment was amplified from DNA isolated from Hamlet, a near-isogenic line carrying 2RL, and bulked DNA from resistant BC3F2 individuals, but not from the recurrent parent Coker 797 or DNA bulks from susceptible BC3F2 plants. Analysis of 111 BC3F2 segregating individuals and BC3F2:3 segregants confirmed the co-segregation of the 3 kb DNA marker with the H21 resistance gene to Hessian fly. Use of this marker could facilitate more rapid screening of plant populations for Hessian fly resistance and monitoring the introgression of H21.
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  • 9
    Electronic Resource
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    Plant molecular biology 35 (1997), S. 167-177 
    ISSN: 1573-5028
    Keywords: comparative genetics ; rice ; barley ; wheat ; Arabidopsis ; flowering time (heading date) ; photoperiod ; vernalization ; earliness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analysis of genes controlling flowering time (heading date) contributes to our understanding of fundamental principles of plant development and is of practical importance because of the effects of flowering time on plant adaptation and crop yield. This review discusses the extent to which plants may share common genetic mechanisms for the control of flowering time and the implications of such conservation for gene isolation from the major cereal crops. Gene isolation may exploit the small genome of rice in map-based approaches, utilizing the conservation of gene order that is revealed when common DNA markers are mapped in different species. Alternatively, mechanisms may be conserved within plants as a whole, in which case genes cloned from the model dicot Arabidopsis thaliana provide an alternative route.
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  • 10
    Electronic Resource
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    Plant and soil 188 (1997), S. 309-317 
    ISSN: 1573-5036
    Keywords: chlorsulfuron ; nutrient solution ; roots ; uptake ; wheat ; zinc deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Wheat plants differing in zinc efficiency (Excalibur; Zn-efficient, Gatcher and Durati; Zn-inefficient) were grown in HEDTA chelate-buffered nutrient solution in controlled conditions and supplied with 0 or 40 μg chlorsulfuron L-1 . Zinc uptake rates of 12-d-old plants were measured over 80 or 90 minutes using65 Zn added to nutrient solutions. Increasing the zinc concentration of the solution increased the rate of zinc uptake, while the percentage of zinc transported to shoots was decreased. Addition of chlorsulfuron to uptake solutions for 90 minutes did not influence rate of zinc uptake or transport of zinc to shoots. Pretreating plants with chlorsulfuron for 5 days decreased zinc uptake rates, but transport to shoots was proportionally increased. Three-day pretreatment with chlorsulfuron was the minimum required for significant differences in uptake and transport of zinc to occur. Plants exposed to chlorsulfuron for 3 days required a further 5 days of growth in chlorsulfuron-free solutions before uptake rates recovered to control plant rates. It is concluded that chlorsulfuron deleteriously but reversibly affects uptake of zinc across the plasma membrane after prolonged exposure.
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  • 11
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    Plant and soil 197 (1997), S. 95-103 
    ISSN: 1573-5036
    Keywords: drought ; mycorrhizal fungi ; safflower ; water relations ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The influence of arbuscular mycorrhizal fungi on drought tolerance and recovery was studied in safflower (Carthamus tinctorius L.) and wheat (Triticum aestivum L.). Plants were grown with and without the mycorrhizal fungus, Glomus etunicatum Becker & Gerd., in nutrient-amended soil under environmentally-controlled conditions to yield mycorrhizal and nonmycorrhizal with similar leaf areas, root length densities, dry weights, and adequate tissue phosphorus. When drought stress was induced, mycorrhizal infection did not affect changes in leaf water, osmotic or pressure potentials, or osmotic potentials of leaf tissue rehydrated to full turgor in either safflower or wheat. Furthermore, in safflower, infection had little effect on drought tolerance as indicated by the level of leaf necrosis. Mycorrhizal wheat plants, however, had less necrotic leaf tissue than uninfected plants at moderate levels of drought stress (but not at severe levels) probably due to enhanced phosphorus nutrition. To determine the effects of infection on drought recovery, plants were rewatered at a range of soil water potentials from –1 to –4 MPa. We found that although safflower tended to recover more slowly from drought after rewatering than wheat, mycorrhizal infection did not directly affect drought recovery in either plant species. Daily water use after rewatering was reduced and was correlated to the extent that leaves were damaged by drought stress in both plant species, but was not directly influenced by the mycorrhizal status of the plants.
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  • 12
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    Plant and soil 197 (1997), S. 79-86 
    ISSN: 1573-5036
    Keywords: dwarfing genes ; root and stem mass ratios ; root dry-weight ; root length ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of Rht alleles on root growth and distribution in isogenic lines of spring wheat (Triticum aestivum L.) are described under different environmental conditions. Above-ground biomass, root length, root dry-weight and their distribution along the soil profile were measured by destructive sampling for growth of aerial biomass and extraction of soil cores containing roots. Field experiments were conducted under non-limiting water and nutritional conditions during two consecutive years, using an early and a late sowing date each year. Dwarfing genes significantly reduced plant height and above-ground biomass at anthesis. In addition, stem mass ratio also was reduced with increases in the allelic dosage. Conversely, total root length and root dry-weight per unit area at anthesis were increased with decreased plant height, therefore, root mass ratio tended to be negatively correlated with plant height. Differences in distribution of root length and root dry-weight through the soil profile among lines were largely confined to the upper soil layers (i.e. the top 30 cm). Differences in root dry-weight were more important than in root length, so that the dwarf line had the highest root mass per unit root length. Furthermore, a significant positive correlation between the root mass ratio and stem mass per unit stem length was found. It is suggested that increases in root mass per unit root length associated with Rht alleles are evidencing a surplus of photoassimilates during stem elongation which are used for thickening the roots due to the lack of alternative sinks. Agronomic implications of this effect are discussed.
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  • 13
    Electronic Resource
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    Plant and soil 190 (1997), S. 267-277 
    ISSN: 1573-5036
    Keywords: dynamic model ; root growth ; root impacts ; root-shoot ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The simulation of crop - soil systems with a model requires an appropriate description of the root dynamics. An empirical root growth model that simulates root-shoot relations, root distribution and a dynamic response to environmental conditions is presented. The root model extends an existing crop model and links it to a soil model to calculate dry matter accumulation, water and nitrogen dynamics of a wheat crop. Simulated roots are distributed over soil layers according to carbon supply from the shoots by using a 'top down principle'. This principle favours the top layers for root growth by first providing all available carbon to the first layer. Under unfavourable soil conditions in that layer, carbon is given to the next deeper soil layer. This procedure is repeated until a separately calculated rooting depth is reached. At that depth all available carbon is used for root growth regardless of current soil conditions. Under most simulated conditions the 'top down principle ' results in a negative exponential function of a monotone decrease of root distribution with soil depth. However, it can also account for larger root densities deeper in the profile when water or nitrogen deficiency occurs in soil. In addition to soil water and soil nitrogen supply the root model considers soil compaction, aeration and root distribution history for root growth simulation. The new model, consisting of an existing crop and soil model and linked through a new developed root model, was calibrated and tested using two independent field experiments. A sensitivity analysis was carried out by varying parameters, initial soil conditions and hypothetic weather patterns as part of the validation process. Root length density distribution (r2(1:1)=0.65), shoot, grain and total root biomass (r2(1:1)=0.87) were predicted satisfactorily, thus providing a useful tool for specific simulation studies on that site.
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  • 14
    ISSN: 1573-5060
    Keywords: Puccinia striiformis ; Triticum aestivum ; association of components ; stripe rust ; durable resistance ; infection frequency ; latency period ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Latency period, infection frequency, lesion length, lesion growth, disease severity and percentage of infected leaf parts were assessed on 10-day-old seedling leaves and flag leaves of ten bread wheat (Triticum aestivum L.) cultivars after inoculation with urediospores of Puccinia striiformis Westend. f. sp. tritici. For all components significant genotypic differences were detected. Components of resistance tended to be associated. A long latency period was associated with a low infection frequency, small lesions, a low disease severity and a low percentage of infected leaf parts. The latency period, measured as time period until first pustule appearance (LP1), was highly correlated with the latency period measured as time period until 50% of the pustules appeared (LP50). Assessment of latency period of large numbers of cultivars could therefore be reliably done by measuring LP1 which is less time consuming than measuring LP50. Latency period, infection frequency and disease severity were highly correlated with disease development data from field experiments. These results suggest that selection in the greenhouse for one of these components should result in cultivars with high levels of quantitative resistance. Disease severity after uniform inoculation in the greenhouse can be used for monocyclic evaluations because it is the easiest to assess.
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  • 15
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    Euphytica 97 (1997), S. 39-44 
    ISSN: 1573-5060
    Keywords: Agropyron ; Elymus ; Fusarium head blight ; scab ; resistance ; genetic resources ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Four species of indigenous Japanese Agropyron, namely, Elymus humidus Osada (= Agropyron humidum), E. tsukushiensis Honda var. transiens (= A. tsukushiense), E. racemifer Tsvel. (= A. ciliare) and A. mayebaranum var. intermedium Hatusima were collected and evaluated for their resistance to Fusarium head blight (FHB, scab) after inoculation with a conidial suspension of Fusarium graminearum Schwabe at the flowering stage. The resistance to penetration of FHB and to fungal invasion of rachis internodes was evaluated in each accession in a comparison with six wheat cultivars. The results demonstrated that AG.91-35 of E. humidus and AG.91-24 of E. racemifer had higher resistance to penetration than the resistant wheat cultivars Nobeokabouzu-komugi and Sumai 3, respectively. All accessions of indigenous Japanese species of Agropyron examined, with the exception A. mayebaranum, had a statisticallysimilar resistance to invasion, which was the same as that of Nobeokabouzu-komugi or Sumai 3. In all accessions of E. humidus, with only one exception, no spread of the fungus from the infected spikelets to the rachis internodes was detected at all. The possible application of the strains of Agropyron as genetic resources for development of resistance to FHB in wheat is discussed.
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  • 16
    ISSN: 1573-5060
    Keywords: dwarfing genes ; wheat ; radiation interception ; radiation use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three near isogenic lines of spring wheat grown to determine whether Rht dwarfing alleles alter radiation interception. A field study (involving two sowing dates in two growing seasons) with lines containing different allelic dosage of Rht1 and Rht2 (i.e. dwarf, DD; semi-dwarf, SD and tall SH), was conducted without water and nutritional deficiencies. Dwarfing genes did not modify the timing of occurrence of phenological events. Above-ground biomass at anthesis was reduced by 22% in the DD line in relation of the rest of the lines. However, at maturity accumulated biomass of the DD and SH lines were not significant different. Dwarfing genes increased the light attenuation coefficient (k, with values of 0.48, 0.62 and 0.78 for the SH, SD and the DD line respectively). A similar trend was followed to the leaf thickness (estimated by the specific leaf weight, SLW). Despite the differences observed among the lines, both in k and SLW values, they did not differ significantly in the proportion of incoming radiation intercepted by the canopy, nor in the cumulative intercepted radiation during the pre and post-anthesis periods. Radiation use efficiency (RUE) differed significantly among the lines. While RUE during pre-anthesis was the lowest in the DD line, from anthesis to maturity the lines with Rht alleles showed higher RUE values than the SH line. The low pre-anthesis RUE in the DD lines could be associated with (i) poor canopy architecture due to reductions in leaf sheath and internode lengths and/or (ii) reduced canopy CO2 exchange rate. Post-anthesis RUE was lower than that recorded pre-anthesis in all lines. But the magnitude of the reduction was inversely related to the doses of the Rht alleles. Post-anthesis RUE appeared to be closely and positively associated with the number of grains set per unit biomass at anthesis. This relationship suggests a regulatory effect of the sink size on the efficiency of the crop to convert radiation into biomass during this period.
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  • 17
    ISSN: 1573-5036
    Keywords: boron ; rice-wheat rotation ; sterility ; time of sowing ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Spikelet sterility in wheat (Triticum aestivum L.) is emerging as a production threat in different parts of Nepal. This study was aimed at determining the effects of sowing date and boron application in controlling spikelet sterility in four different genotypes of spring wheat in a rice-wheat system in the western hills of Nepal. Four genotypes of known different responses to boron were planted on 21 November, 6 December and 21 December, 1994 with or without boron application at 1 kg B ha-1 (i.e. 9 kg borax ha-1) on a soil that was known to be deficient in boron. The effect of sowing date was significant for the phenology, yield components, percentage sterility and grain yield. Sterility was significantly increased in the crop planted on 21 December, which had also the lowest 1000 seed weight and grain yield; there was an almost 50% grain yield reduction compared to the crop planted on 21 November. Terminal moisture stress (i.e. lack of moisture during the later part of the development) was observed in the late sown crop which also amplified the extent of sterility associated with boron deficiency. Genotypes differed in response to sowing dates and boron treatment for all of the phenological events measured, yield components, grain yield and percentage sterility. SW-41 and BL-1022 had significantly higher sterility at all sowing dates. BL-1249 showed a consistently lower% sterility over all sowing dates and boron treatments. The addition of boron significantly increased the number of grains set per spike thereby decreasing the total sterility in boron responsive genotypes SW-41 and BL-1022 while those not susceptible did not respond. The boron concentration in the flag leaf at anthesis was increased in treatments with added B in the soil but genotypes did not differ in boron concentration for any soil treatment.
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  • 18
    ISSN: 1573-5036
    Keywords: arbuscular mycorrhiza ; hydroponics ; linseed ; sorghum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Linum usitatissimum, Sorghum bicolor and Triticum aestivum plants were further colonised by the arbuscular mycorrhizal fungus, Glomus mosseae, during a four week period of hydroponic culture after a pre-culture period of three weeks with the fungus in perlite substrate. The viability of mycorrhizal colonisation of T. aestivum was indicated by an initial experiment where G. mosseae from mycorrhizal plants colonised non-mycorrhizal plants when the plants were grown together in the same hydroponic container using modified Long Ashton nutrient solution. Intermittant aeration of the plant roots (2 h periods, four times per day) provided a compromise between adequate aeration and minimal disturbance of the fungus. In a second experiment, two nutrient media, modified Long Ashton and modified Knop plus Hoagland medium were compared for culturing G. mosseae on T. aestivum. A significantly higher root dry weight was found for the mycorrhizal versus the non-mycorrhizal wheat plants in modified Long Ashton nutrient medium, which contained 10 µM P and an organic buffer. Modified Knop plus Hoagland nutrient medium contained a high P concentration (0.9 mM) and did not produce viable cultures of mycorrhizal colonisation. In a third experiment, modified Long Ashton medium was used for hydroponic culture of mycorrhizal L. usitatissimum, S. bicolor and T. aestivum. The root colonisation percentages for T. aestivum (73%), S. bicolor (36%) and L. usitatissimum (65%) were within the range of colonisation rates obtained with solid substrate culture in perlite. Viability of the mycorrhizal structures in hydroponic culture was assessed by monitoring activity of fungal succinate dehydrogenase and found to be similar to cultures in perlite. No difference in the P concentration of mycorrhizal and non-mycorrhizal plants was observed, possibly owing to the lack of diffusion limits for P in hydroponic solution. This report describes a system for the viable culture of G. mosseae with different plant species where a high mycorrhizal colonisation rate was produced under conditions of a short culture period using intermittent aeration, a low concentration of P supply and an organic buffer.
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  • 19
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; Hordeum vulgare ; wheat ; barley ; chromosome addition lines ; translocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two disomic barley chromosome addition lines and five translocated chromosome addition lines of common wheat cultivar Shinchunaga were isolated. They were derived from a hybrid plant between Shinchunaga and cultivated barley Nyugoruden (New Golden) by backcrossing with wheat and self pollination. Barley chromosomes added to chromosome arms involved in the translocated chromosomes were identified by C-banding method and by crossing these lines with Chinese Spring/Betzes addition lines. Two disomic addition lines were identified to have chromosome 6 and 7 of barley, respectively. Two of the five translocated chromosome addition lines were clarified to have same chromosome constitution, 42 wheat chromosomes and a pair of translocated chromosomes constituted with a long arm of chromosome 5B of wheat and a short arm of chromosome 7 of barley. The other three lines could not be identified due to chromosome rearrangement. Performances of these seven lines on agronomic characters were examined. Addition of barley chromosome 7 induced early heading, and chromosome 6 showed lated heading. Almost all of the lines except that of chromosome 6 showed short culm length and all showed reduced number of tillers, spikelets and grains per ear, and low seed fertility. These lines would be useful for genetic analyses in wheat and barley and for induction of useful genes of barley into wheat.
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  • 20
    ISSN: 1573-5060
    Keywords: clustering procedure ; genotype × environment interaction ; multi-trait analysis ; quality ; wheat ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Structure of genotype × environment interaction was studied in two series of trials for three quality traits in bread wheat. Two kinds of environments were present in each series of trials: macro-environments defined as locations or location × year combinations and micro-environments induced by diversified cultural practices within each site. For each trait, a simultaneous clustering procedure was used to identify groups of environments which were homogeneous for interaction. An optimised series of trials was proposed from the clusters obtained. The cultural practice based on nitrogen fertilisation seemed to better diversify environments for interaction than use of fungicide, when all quality traits were considered. Determining an optimised series of trials simultaneously for the three traits led to keeping more environments than when one trait was considered. Suggestions for establishing a series of trials for a multi-trait analysis were proposed.
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  • 21
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    Euphytica 93 (1997), S. 353-360 
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; Secale cereale ; powdery mildew ; Erysiphe graminis f.sp. tritici ; resistance ; suppression ; segregation distortion ; wheat ; rye
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The location of wheat gene Pm8 for resistance to powdery mildew in the 1RS chromosome segment derived from cereal rye cultivar Petkus was confirmed. There was reduced transmission of the 1BL.1RS chromosome relative to its wheat homologue in four of the five crosses examined. Pm8 was not expressed in some wheat cultivars and selections which possessed the 1RS chromosome identified by the presence of relevant genes for resistance to the three rusts, due to the presence of a dominant suppressor gene(s) in the wheat genome. The frequency of suppression in 1BL.1RS wheats from Mexico was significantly higher than in a group of wheats (both local and exotic) introduced from China and was probably much higher than in European wheats.
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  • 22
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    Euphytica 94 (1997), S. 31-36 
    ISSN: 1573-5060
    Keywords: Triticum ; Fusarium graminearum ; resistance ; head scab ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Multi-floret and single-floret injection inoculation methods were used to test 1076 accessions of Triticum for resistance to initial infection and resistance to pathogen spread within spike tissue respectively. The data obtained between years or inoculation dates were comparatively similar and were little influenced by climatic factors, especially humid condition. All the tested materials uniformly exhibited susceptibility to initial infection, but there were great differences in resistance to spread among species or cultivars. The diploid and tetraploid wheats were severely susceptible. Only 30 genotypes of common wheat of T. aestivum concv. vulgare showed high resistance to spread. The highest frequency of high spread resistance existed in these landraces which were distributed in Zhejiang, Hubei, Hunan, Jiangsu provinces and Shanghai City, Guizhou, Sichuan and Yunnan provinces ranked second. The majority of wheat landraces from Hebei, Shanxi, Shaanxi Province and Beijing City showed susceptibility or high susceptibility. No resistance was found in Tibetian wheats.
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  • 23
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    Euphytica 94 (1997), S. 279-286 
    ISSN: 1573-5060
    Keywords: Triticum turgidum ; T. monococcum ; T. boeoticum ; T. urartu ; wheat ; Puccinia striiformis ; stripe rust ; rust resistance ; amphiploid ; suppressors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Stripe rust (caused by Puccinia striiformis Westend.) is a wheat disease of worldwide importance. Seedlings of 75 accessions of Triticum boeoticum, 12 of T. monococcum, 16 of T. urartu, 230 of durum wheat (T. turgidum L. var. durum), and 128 amphiploids (genome AAAABB) involving the crosses of the three diploid species (AA) with T. turgidum (AABB) were evaluated in the greenhouse for their reaction to P. striiformis race 14E14. Durum wheats and the amphiploids were also evaluated at two field locations in Mexico with the same race for their adult plant response. Resistant seedling reactions (infection types: 0-3 on a 0-9 scale) were seen for 10 (13%) accessions of T. boeticum, 19 (8%) accessions of T. turgidum and 32 (25%) amphiploids. The remaining accessions were either moderately resistant (ITs 4-6) or susceptible (ITs 7-9). The three amphiploids derived from the crosses of seedling resistant T. boeoticum and T. turgidum, were resistant as seedlings. Among the 51 amphiploids involving one resistant parent, 29 were resistant and the remaining 22 displayed intermediate to susceptible reactions. Suppressors for resistance were common in the A and AB genomes and suppression was resistance gene specific. Forty-five (20%) durums showed adequate field resistance (relative AUDPC 〈10% of the susceptible check ‘Morocco’). These included the 19 seedling resistant durums. Presence of genes involved in adult plant resistance was evident, because 26 of the remaining adult plant resistant durums had displayed intermediate-susceptible seedling reactions. Though the seedling reactions of the amphiploids varied from low to high, all involving the adult plant resistant durums possessed adequate field resistance. The resistant, newly produced, AAAABB amphiploids are useful genetic resources for stripe rust resistance which could be transferred to the cultivated T. turgidum.
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  • 24
    ISSN: 1573-5060
    Keywords: Israel ; landraces ; Puccinia recondita ; Puccinia striiformis ; disease resistance ; wheat ; Triticum spp. ; leaf rust ; yellow rust
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The purpose of this study was to identify the species of local landraces of wheat (Triticum spp.), held in the Israel Gene Bank, to evaluate them for basic characters and to assess their response to infection by two rust fungi under artificial inoculation conditions. One-hundred-thirty one seed samples were collected from local or Beduin farmers during 1978–1981 throughout the Galilee, Mt. Gilboa. Judean Desert and the south Negev. The samples were collected and stored in the Israel Gene Bank without any characterization or evaluation. Each accession was planted in a 1 m row at Bet Dagan and grown under favorable conditions for plant growth and rust development. Determination of the species, data of plant height, days to heading and reaction of the landraces to artificial inoculation with a composite inoculum of Puccinia recondita and P. striiformis were collected from each row. A small part of the landraces collection consisted of mixed populations of T. durum and T. aestivum plants, where one of the two species was predominant. One-hundred-fourteen and 17 accessions from this collection represented, respectively, Triticum durum and T. aestivum Israel landraces. Large variations were found for all the characters examined. Of the total accessions, 6.5% (8 accessions) and 32% (42 accessions) were resistant, respectively, to yellow- and leaf-rust. It was concluded that the diversified populations of the local landraces of wheat can be used as a source not only for genes affecting basic characters such as plant height and heading date, but also for resistance to leaf rust and yellow rust.
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  • 25
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    Euphytica 94 (1997), S. 257-261 
    ISSN: 1573-5060
    Keywords: centric breakage and fusion ; translocation ; substitution ; wheat ; rye
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Complete chromosomes 1R and 1B were reconstructed in wheat from the centric wheat-rye translocation 1RS.1BL. Three substitutions: 1R(1A), 1R(1B), 1R(1D), and three new centric translocations: 1RS.1AL, 1RS.1BL, 1RS.1DL were produced from the reconstructed chromosome 1R. Each one of these has the same rye chromosome arm 1RS which was present in the original translocation 1RS.1BL of ‘Kavkaz’ wheat. Reconstructed chromosome 1B and a normal chromosome 1R were used to produce a new 1RS.1BL translocation. This translocation has the long arm from the original 1RS.1BL translocation of ‘Kavkaz’, but a different 1RS arm. The third generation centric translocations were mitotically stable and were normally transmitted to progeny. Misdivision frequency of the reconstructed chromosomes 1R did not change relative to normal 1R, whereas the misdivision frequency of the two reconstructed chromosomes 1B tested was significantly higher relative to normal 1B. These experiments demonstrate that repeated cycles of centric breakage and fusion do not impair the function of centromeres in wheat and rye but may change chromosome's susceptibility to misdivision.
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  • 26
    ISSN: 1573-5060
    Keywords: Boron ; genotypic variability ; sterility ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two field experiments were carried out at the Khairanitar Farm, Nepal during the winter season of 1993 to investigate whether wheat genotypes differ in their sterility response to low soil boron and whether boron added to soil can correct sterility. A nursery consisting of 41 diverse genotypes from Nepal, India, Bangladesh, Thailand, China, Pakistan and CIMMYT/Mexico were evaluated in a plot where severe sterility had been observed in previous years. The second experiment involved six genotypes of known sterility responses to boron grown with or without an application of boron at 1 kg ha-1. Large differences were observed among genotypes in terms of number of grain set per ear (range 0.5 to 30 ) and sterility (5.5% to 97.5%). About one third of all the genotypes had 〈25% sterility and 16 of them suffered 〉75% sterility. The genotypes Fang-60, Sonalika, De Mai 6-22, BUC/FLK/MYNA/VL and HDW-234 were highly tolerant to boron deficiency with 〈10% sterility. In sharp contrast, genotypes BOW/BUT, SERI/THB, Glennson, SW-41, Yunmai-33 and UHU were highly susceptible and set virtually no grains in the boron deficient plots. Strong responses to boron application were observed and genotypic variations were evident. Boron at 1 kg ha-1significantly reduced the number of late ears, increased number of grains per ear and grain yield in boron-responsive genotypes. Tolerant genotypes were not influenced by added boron. Given these striking genetic differences, progress in breeding wheat for B-deficient soils in Nepal should be worthwhile.
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  • 27
    ISSN: 1573-5087
    Keywords: auxin ; immunoassay ; nitrogen nutrition ; root growth ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Average root length, root/shoot ratio and auxin content in roots were higher in plants supplied with nitrate rather than ammonium and grown at 18, 21, 24°C. The effects on root length were most pronounced at the highest temperatures (21 and 24°C); and the warmer the temperature, the earlier appearance of the differences in growth rate between NO3- and NH4-fed plants. A sharp acceleration of root growth was characteristic of NO3-fed plants grown at 21 and 24°C and was associated with a temporary increase in auxin concentration measured by immunoassay.
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  • 28
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    Plant growth regulation 21 (1997), S. 169-175 
    ISSN: 1573-5087
    Keywords: chilling ; drought ; heat ; paclobutrazol ; paraquat ; propiconazole ; protection ; tetraconazole ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The stress protective effects of triazoles including paclobutrazol, a plant growth regulator, and two fungicides, propiconazole and tetraconazole, are compared. Wheat (Triticum aestivum L. cv Katepwa) seeds were imbibed for 18 h in distilled water (Ck) or in aqueous solutions of each triazole (50 mg L-1). Seeds were then air dried, planted in sectioned plastic flats and grown in a greenhouse. After 10 days, one set of seedlings were allowed to continue growing under optimal conditions while additional sets were exposed to various stresses including high temperatures, drought and spray with the herbicide paraquat. Compared to wheat leaves from plants grown under optimal conditions, heat stress decreased shoot fresh weight, fluorescence values and chlorophyll levels. It also increased ion leakage. All symptoms of damage were alleviated by the triazoles, with paclobutrazol being the most potent. Similar trends were found under acute drought conditions, where seedlings treated with paclobutrazol had the highest percent survival and the most shoot regrowth upon rewatering. Paclobutrazol was also the best triazole in protecting wheat leaves from damage caused by paraquat, a free radical generator. It is concluded that while all the triazoles have the potential to be stress protectants, paclobutrazol was consistently the most effective.
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  • 29
    ISSN: 1573-1561
    Keywords: α-Amylase inhibitors ; trypsin inhibitors ; cereal endosperm ; wheat ; barley ; Spodoptera frugiperda ; digestive enzymes ; midgut proteases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The α-amylase activity was determined throughout the larval development of Spodoptera frugiperda. Maximal activities with optimal pH in the range 8.5–9.5 were found in last instars. Protein preparations enriched in heterotetrameric inhibitors from wheat flour were active towards gut amylases from last instars, while those corresponding to homodimeric and monomeric inhibitors showed low inhibition levels. These results were further supported by testing purified members of each inhibitor type and by analyzing the effects of the inhibitors on the amylase isoenzyme pattern from native PAGE. High levels of trypsin-like activity were also found in gut extracts from last instars. Different genetic variants of the major barley trypsin inhibitor were active against this gut enzyme. None of the other larval digestive protease activities (chymotrypsin-like, elastase-like, leucine aminopeptidase-like, and carboxypeptidase A and B-like) were inhibited, indicating that the barley inhibitor is specific towards trypsin-like enzymes.
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  • 30
    ISSN: 1573-1561
    Keywords: Spacing pheromones ; olfactometry ; aphids ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Olfactometry using an apterous individual of Rhopalosiphum padi (L.) showed an arresting effect by volatiles from a wheat seedling and a repellent effect by volatiles from a wheat seedling infested with aphids at a high population density (ca. 9 aphids/cm2). Four compounds, 6-methyl-5-hepten-2-one, (−)- and (+)-6-methyl-5-hepten-2-ol, and 2-tridecanone, were identified by GC-MS in air entrainments from the wheat seedlings with high aphid density but not from the wheat seedlings alone. The mixture of the four compounds in the natural proportion counteracted the attractivity of the volatiles from the intact uninfested wheat seedling. The likely role of these compounds in the spacing behavior of this aphid species, when present in high densities on wheat, is discussed.
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  • 31
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    Journal of chemical ecology 23 (1997), S. 543-551 
    ISSN: 1573-1561
    Keywords: Temperature ; photoperiod ; hydroxamic acids ; growth ; defense ; secondary metabolites ; wheat ; Gramineae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effects of temperature and photoperiod on accumulation of hydroxamic acids (Hx) in wheat (Triticum aestivum L.) seedlings were evaluated under laboratory conditions. Hx concentrations were significantly higher at higher temperatures. No such clear trend was found for the photoperiod effect. The significant effect of temperature and photoperiod on growth rate of seedlings and the significant positive correlation between growth rate prior to analysis and levels of Hx, suggested that environmental effects on Hx accumulation were at least partially mediated through their effect on plant growth rate. After uncoupling the effect of environmental conditions from the effect of plant growth rate by statistical means the effect of temperature on Hx was no longer significant. Therefore, temperature effect was fully mediated by plant growth rate. Implications of the patterns found are discussed in issues of plant-defense general theories.
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  • 32
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    Mitigation and adaptation strategies for global change 1 (1997), S. 273-288 
    ISSN: 1573-1596
    Keywords: climate change ; vulnerability ; adaptation ; agriculture ; Spain ; wheat ; maize
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Abstract This study evaluates the theoretical impact of climate change on yields and water use of two crops with different responses to increased CO2 and which represent contrasting agricultural systems in Spain. In all cases the simulated effects of a CO2-induced climate change depended on the counteracting effects between higher daily ET rates, shortening of crop growth duration and changes in precipitation patterns as well as the simulated effects of CO2 on the water use efficiency of the crops. For summer irrigated crops such as maize, the yield reductions and the exacerbated problems of irrigation water availability simulated with climate change may force the crop out of production in some regions. For winter dryland crops such as wheat, productivity increased significantly in some regions, suggesting a northward shift of area suitable for wheat production in future climates. The study considered strategies for improving the efficiency of water use based on the optimization of crop management decisions in a CO2-driven warmer climate.
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  • 33
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    Mitigation and adaptation strategies for global change 1 (1997), S. 273-288 
    ISSN: 1573-1596
    Keywords: climate change ; vulnerability ; adaptation ; agriculture ; Spain ; wheat ; maize
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Abstract This study evaluates the theoretical impact of climate change on yields and water use of two crops with different responses to increased CO2 and which represent contrasting agricultural systems in Spain. In all cases the simulated effects of a CO2-induced climate change depended on the counteracting effects between higher daily ET rates, shortening of crop growth duration and changes in precipitation patterns as well as the simulated effects of CO2 on the water use efficiency of the crops. For summer irrigated crops such as maize, the yield reductions and the exacerbated problems of irrigation water availability simulated with climate change may force the crop out of production in some regions. For winter dryland crops such as wheat, productivity increased significantly in some regions, suggesting a northward shift of area suitable for wheat production in future climates. The study considered strategies for improving the efficiency of water use based on the optimization of crop management decisions in a CO2-driven warmer climate.
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  • 34
    ISSN: 1572-9680
    Keywords: canopy pruning ; cereals ; pulses ; root pruning ; tree-crop competition ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Growth of trees and seasonal yields of understory crops were measured over a 5-year period for 4 crops grown under 17 tree species at 8 × 8 m spacing in wetland rice fields. All tree species grew well in rice fields, at rates comparable to their growth in forest plantations. Top and root pruning reduced average tree girths by up to 19% and average tree volumes by up to 41%, depending on intensity of pruning. The crops monitored were Oryza sativa, Triticum aestivum, Corchorus olotorius, and Lens culinaris. Crop yields under the trees averaged 93% of the corresponding yields outside the tree canopy. The most important factor affecting the yields of undercrops was tree size (height and/or girth). Differences among tree species and the interaction with species of undercrops were not significant after controlling for tree size. Pruning of roots and branches significantly improved crop yields under trees by amounts proportional to the intensity of root or top pruning.
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  • 35
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    Genetic resources and crop evolution 44 (1997), S. 301-306 
    ISSN: 1573-5109
    Keywords: genetic variability ; high molecular weight glutenin subunits ; storage proteins ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The high molecular weight glutenin subunits (HMW-GS) composition at the Glu-1 complex loci, in 23 old original wheat genotypes cultivated in Slovakia several decades ago and 32 modern Slovak and Czech wheat cultivars growed in Slovakia at present were studied by SDS-PAGE. Some of the HMW-GS – subunit pairs 3+12, 17+18, and subunit 20, present in old “historical” wheats were missing in modern cultivars utilized in Slovakia nowadays. There were observed 15 different HMW-GS encoded by 11 alleles or allelic pairs in old genotypes. Lower number of different HMW-GS and competent alleles were observed in a set of modern wheat cultivars – 11 different HMW glutenin subunits encoded by 8 alleles or allelic pairs. The same number of different HMW-GS patterns was revealed in both sets of wheats. From the point of view of genetic variability, it could be concluded that long-term effort of breeders and decreasing of cultivation of landraces and old cultivars are associated with the loss of several HMW-GS alleles and decreasing of genetic variability of wheats. Molecular characterization can reveal broad allelic variability of old wheat genotypes and landraces. Their maintenance in genetic resource collections can prevent losses of these interesting genes.
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  • 36
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    Genetic resources and crop evolution 44 (1997), S. 211-215 
    ISSN: 1573-5109
    Keywords: Fusarium graminearum ; resistance ; Roegneria ; scab ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract 71 accessions from 13 Roegneria species were evaluated for resistance to wheat scab. The results showed that 31 of the 71 accessions possessed high resistance (HR) to initial infection and high resistance (HR) to pathogen spread. The disease spread from inoculated floret to head rachis was not observed, and the incidence of head infection were lower under natural than under artificial inoculation conditions. The intergeneric hybrid F1 of Roegneria tsukushiensis (Honda) B.R. Lu, Yen et J.L. Yang. var. transiens (Hack.) B.R. Lu, Yen et J.L. Yang × Hordeum vulgare Linn. exhibited resistance (R) to pathogen invasion and high resistance (HR) to spread. Therefore, Roegneria could be used as scab resistant resources in cereal breeding. In addition, the relatioship between its resistance and ecological environments where Roegneria was distributed was discussed in this paper.
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  • 37
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    Euphytica 95 (1997), S. 209-219 
    ISSN: 1573-5060
    Keywords: gene expression ; gluten ; glutenin ; protein fingerprint ; Triticum turgidum ; var. dicoccoides ; wheat ; Triticum aestivum ; Triticum durum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Wheat seed storage protein fingerprint is used to determine the gluten protein pattern in studies aimed at improving flour quality. Wild wheat with high seed protein content is used extensively in wheat breeding programs. Although the wild wheat growth and protein content may be influenced by environmental conditions, the gluten-protein pattern is generally considered as indicative of a genotype, without the superimposition of environmental influences. The effects of soil type, habitat, and deficiencies of N, P, K and S on seed storage protein composition were examined in nine accessions of wild wheat (Triticum turgidum var. dicoccoides) and three varieties (two T. aestivum and one T. durum). Soil from ten natural habitats of the wild wheat that had not previously received any fertilizers or manures was sampled and used to grow wheat in a greenhouse. Seed storage protein composition was characterized by SDS-PAGE. Although deficiencies in soil nutrient caused variations in the seed storage proteins, the genotype was the main factor determining the seed storage protein composition. Seed storage protein composition of genotypes varied when grown under different mineral nutrient conditions. Only one genotype was stable showing almost identical protein patterns under all growing conditions studied without any qualitative change in fingerprint pattern. In the other genotypes, as well as the cultivars, the seed storage protein was affected at least to some extent by the soil. The ‘soil effect’ is summarized in terms of three main quantitative changes in the seeds: 1 – the relative amounts of the high-molecular-weight proteins; 2 – the relative amounts of proteins in the range of 45 and 65 kD; 3 – the percentage distribution of the HMW glutenin and other groups of seed storage proteins. The soild induced also qualitative differences in the composition of seed storage proteins, mostly in those of 45–65 kD. These differences were observed whenever a deficiency of S, N, P, K or Mg was identified. Therefore, in breeding programs that use seed storage protein fingerprints of wild wheat germplasms should be exercise caution when the germplasms selected from wild habitats.
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  • 38
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    Euphytica 96 (1997), S. 257-262 
    ISSN: 1573-5060
    Keywords: boron deficiency ; fertility selective media ; hybridization ; male sterility ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Boron (B) deficiency causes grain set in wheat to fail. A wide range of genotypic variation in the response to low B has been observed. Genotypes were screened in low B in soil and sand culture, and classified into five groups, namely, very sensitive, sensitive, moderately sensitive, moderately tolerant and tolerant. At very low levels of B, the very sensitive to sensitive genotypes were completely male sterile and set only a few or no grain, while the tolerant genotypes set grain normally. Natural outcrossing was detected in these male sterile plants when a tolerant genotype was growing nearby. Grain set by cross fertilisation was markedly enhanced by a B application directly on the ear of the male sterile plants. Three practical implications are suggested. Firstly, genotypes that are tolerant to low B can provide a solution for grain set failure caused by B deficiency. Secondly, the potential for outcrossing in male sterile B deficient wheat has to be taken into account in the maintenance of pure lines in low B soils even though wheat is normally self pollinated. Thirdly, a simple and novel method for hybridization is suggested, in which B deficiency is used as fertility selective medium and male sterile female parents and fertile male parents are provided by genotypic variation in the response to low B.
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  • 39
    ISSN: 1573-5060
    Keywords: lymegrass ; Triticum ; wheat ; wide hybrids ; cytogenetics ; in situ hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A total of 240 F1 hybrids was made beween wheat (Triticum aestivum L. em. Thell. (2n = 6x = 42) and T. carthlicum Nevski (2n = 4x = 28)) and perennial lymegrass (North European Leymus arenarius (L.) Hochst. (2n = 8x = 56) and North American L. mollis (Trin.) Pilger (2n = 4x = 28)). The wide crosses yielded embryos in 20% of caryopses and 96% of the embryos developed into normal hybrid plants. The hybrids were vegetatively vigorous, with evidence of the Leymus rhizomatous habit. Those deriving from L. arenarius survived overwintering in Iceland, but the hybrids L. mollis did not, whereas in a milder environment, both showed perenniality. Cytogenetic analysis of root tip cells before the plants were treated with colchicine showed that 21 out of 28 hybrids investigated had chromosome mosaics, with a population of both amphihaploid and amphidiploid cells. This spontaneous doubling of somatic chromosomes occurred in all cross combinations, with the highest average frequency of diploid cells (28%) in T. carthlicum × L. arenarius crosses. A few selfed seeds have been obtained from a T. aestivum × L. arenarius hybrid. All the hybrids were treated twice with colchicine, but the treatment appeared to have little or no effect on the frequency of chromosome doubling in the hybrids deriving from T. aestivum. The frequency of diploid cells, however, increased significantly (e.g. to 80%) in the hybrids deriving from the T. carthlicum parent. Genomic in situ hybridization confirmed the hybridity of the plants and showed that the hybrids were amphiploids containing genomes of both wheat and lymegrass. In situ hybridization using ribosomal DNA probe differentiated chromosomes of L. mollis, L. arenarius from those of wheat. The hybrids are being backcrossed with lymegrass pollen, aiming to domesticate the wild, perennial species.
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  • 40
    Electronic Resource
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    Plant and soil 188 (1997), S. 101-106 
    ISSN: 1573-5036
    Keywords: acid soil tolerance ; Al tolerance ; selection ; Triticum aestivum L. ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil acidity in the Great Plains of the USA can reduce forage and grain yields of winter wheat, primarily by Al toxicity. Indigenous cultivars may vary in seedling tolerance to Al toxicity, but the benefit that Al tolerance provides to forage and grain production is not well documented in this region. Backcrossed-derived lines of ‘Chisholm’ and ‘Century’ were selected with an additional gene from ‘Atlas 66’ conferring Al tolerance in solution culture. Our objective was to determine the impact of this source of Al tolerance on forage production prior to the jointing stage and subsequent grain yield. Experiments were conducted at several locations on non-limed (pH=4.5–4.7) and limed soils (pH=5.2-6.1) in Oklahoma. Two cultivars (‘TAM 105’, susceptible; ‘2180’, tolerant) with extreme differences in Al tolerance were used as controls . In limed conditions, forage and grain production did not differ between Al-tolerant and -susceptible genotypes, indicating a neutral effect of the Atlas 66 gene in the absence of Al toxicity. Despite visual differences in early-season plant vigor in non-limed acid soil, the Al-tolerant selections did not yield greater season-long forage than their susceptible parents. At sites where Al saturation in the non-limed soil exceeded 30%, spike production at maturity was nearly doubled in the Century background by the addition of Al tolerance, but final grain yield was not significantly improved. In the Chisholm background, grain yield was improved 50 to 74% by Al tolerance. The magnitude of the agronomic benefit of Al tolerance was highly influenced by the edaphic environment and genetic background. Acid soils of the Great Plains appear highly variable in Al toxicity; hence, consideration of the target environment is essential to predict the potential impact of Al tolerance selected in solution culture.
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  • 41
    ISSN: 1573-5036
    Keywords: genotypic differences ; rye ; triticale ; wheat ; zinc deficiency ; zinc efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Field and greenhouse experiments were carried out to study the response of rye (Secale cereale L. cv. Aslim), triticale (× Triticosecale Wittmark. cv. Presto), two bread wheats (Triticum aestivum L, cvs. Bezostaja-1 and Atay-85) and two durum wheats (Triticum durum L. cvs. Kunduru-1149 and C-1252) to zinc (Zn) deficiency and Zn fertilization in severely Zn-deficient calcareus soils (DTPA-Zn=0.09 mg kg-1 soil). The first visible symptom of Zn deficiency was a reduction in shoot elongation followed by the appearance of whitish-brown necrotic patches on the leaf blades. These symptoms were either absent or only slight in rye and triticale, but occurred more rapidly and severely in wheats, particularly in durum wheats. The same was true for the decrease in shoot dry matter production and grain yield. For example, in field experiments at the milk stage, decreases in shoot dry matter production due to Zn deficiency were absent in rye, and were on average 5% in triticale, 34% in bread wheats and 70%, in durum wheats. Zinc fertilization had no effect on grain yield in rye but enhanced grain yield of the other cereals. Zinc efficiency of cereals, expressed as the ratio of yield (shoot dry matter or grain) produced under Zn deficiency compared to Zn fertilization were, on average, 99% for rye, 74% for triticale, 59% for bread wheats and 25% for durum wheats. These distinct differences among and within the cereal species in susceptibility to Zn deficiency were closely related to the total amount (content) of Zn per shoot, but not with the Zn concentrations in shoot dry matter. For example, the most Zn-efficient rye and the Zn-inefficient durum wheat cultivar C-1252 did not differ in shoot Zn concentration under Zn deficiency, but the total amount of Zn per whole shoot was approximately 6-fold higher in rye than the durum wheat. When Zn was applied, rye and triticale accumulated markedly more Zn both per whole shoot and per unit shoot dry matter in comparison to wheats. The results demonstrate an exceptionally high Zn efficiency of rye and show that among the cereals studied Zn efficiency declines in the order rye〉triticale〉bread wheat〉durum wheat. The differences in expression of Zn efficiency are possibly related to a greater capacity of efficient genotypes to acquire Zn from the soil compared to inefficient genotypes.
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  • 42
    ISSN: 1573-5036
    Keywords: addition lines ; rye ; triticale ; wheat ; zinc deficiency ; zinc genetic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Using the disomic wheat-rye addition lines (Triticum aestivum L., cv. Holdfast-Secale cereale L., cv. King-II) and an octoploid triticale line (xTriticosecale Wittmark L. "PlutoxFakon") as well as the respective wheat and rye parents, greenhouse experiments were carried out to study the role of rye chromosomes on the severity of Zn deficiency symptoms, shoot dry matter production, Zn efficiency, shoot Zn concentration and Zn content. Plants were grown in a Zn-deficient calcareous soil with (10 mg Zn kg-1 soil) and without Zn supply. Zinc efficiency was calculated as the ratio of dry weight produced under Zn deficiency to the dry weight produced under Zn fertilization. In the experiments with addition lines, visual Zn deficiency symptoms were slight in the rye cultivar King-II, but were severe in the wheat cultivar Holdfast. The addition of rye chromosomes, particularly 1R, 2R and 7R, into Holdfast reduced the severity of deficiency symptoms. Holdfast showed higher decreases in shoot dry matter production by Zn deficiency and thus had a low Zn efficiency (53 %), while King-II was less affected by Zn deficiency and had a higher Zn efficiency (89 %). With the exception of the 3R line, all addition lines had higher Zn efficiency than their wheat parent: the 1R line had the highest Zn efficiency (80 %). In the experiment with the triticale cultivar and its parents, rye cv. Pluto and wheat cv. Fakon, Zn deficiency symptoms were absent in Pluto, slight in triticale and very severe in Fakon. Zinc efficiency was 88 % for Pluto, 73 % for triticale and 64% for Fakon. Such differences in Zn efficiency were better related to the total amount of Zn per shoot than to the amount of Zn per unit dry weight of shoot. Only in the rye cultivars, Zn efficiency was closely related with Zn concentration. Triticale was more similar to rye than wheat regarding Zn concentration and Zn accumulation per shoot under both Zn-deficient and Zn-sufficient conditions. The results presented in this study show that rye has an exceptionally high Zn efficiency, and the rye chromosomes, particularly 1R and 7R carry the genes controlling Zn efficiency. To our knowledge, the result with triticale and its rye parents is the first report showing that the genes controlling Zn efficiency in rye are transferable into wheat and can be used for development of new wheat varieties with high Zn efficiency for severely Zn-deficient conditions.
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  • 43
    ISSN: 1573-5036
    Keywords: genotype ; remobilisation ; seed nutrient content ; seedling ; wheat ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The changes in nutrient content of grain tissues and seedling parts of two wheat genotypes (Triticum aestivum L., Excalibur and Janz) with low or high seed Zn content were followed from imbibition to early seedling development (12 days). The grains were separated into seed coat, endosperm and embryo, while the seedlings were separated into roots and shoots. The dry weight of the seed coat did not change throughout the experimental period, whereas the endosperm weight declined rapidly from day 4 onward. The weight of embryo did not show any difference between and within cultivars. About a half of seed Zn was remobilised into shoot and roots during 12 days of growth, regardless of the initial seed Zn content in both genotypes. The seed coat contained 55–77% of the total seed nutrients in the two wheat genotypes, except in the case of S (around 40%). Manganese, Fe, Ca, K, and P were remobilised effectively from the seed coat as well as from the endosperm, while remobilisation of Zn and Cu was relatively less from the seed coat than from the endosperm. After 10 days of growth, all nutrients monitored were completely remobilised from the endosperm. Remobilised K was directed primarily into shoots; an increase in K content in shoots was relatively higher than the accumulation of dry matter, with a consequent increase in K concentration in shoot tissue. The remobilisation of some nutrients (eg. Fe, Ca and Zn) from various grain tissues during inbibition, germination and early growth is different from the remobilisation in more mature plants.
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  • 44
    ISSN: 1573-5036
    Keywords: Azorhizobium caulinodans ; crack entry ; intercellular colonization ; naringenin ; rice ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Recently, evidence has been obtained that naturally occurring rhizobia, isolated from the nodules of non-legume Parasponia species and from some tropical legumes, are able to enter the roots of rice, wheat and maize at emerging lateral roots by crack entry. We have now investigated whether Azorhizobium caulinodans strain ORS571, which induces root and stem nodules on the tropical legume Sesbania rostrata as a result of crack entry invasion of emerging lateral roots, might also enter rice and wheat by a similar route. Following inoculation with ORS571 carrying a lacZ reporter gene, azorhizobia were observed microscopically within the cracks associated with emerging lateral roots of rice and wheat. A high proportion of inoculated rice and wheat plants had colonized lateral root cracks. The flavanone naringenin at 10 and 10 M stimulated significantly the colonization of lateral root cracks and also intercellular colonization of wheat roots. Naringenin does not appear to be acting as a carbon source and may act as a signal molecule for intercellular colonization of rice and wheat by ORS571 by a mechanism which is nod gene-independent, unlike nodule formation in Sesbania rostrata. The opportunity now arises to compare and to contrast the ability of Azorhizobium caulinodans with that of other rhizobia, such as Parasponia rhizobia, to intercellularly colonize the roots of non-legume crops.
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  • 45
    ISSN: 1573-5036
    Keywords: Azospirillum brasilense ; evolution ; nifA-lacZ ; nifH-lacZ ; nitrogen fixation ; para-nodules ; symbiosis ; wheat ; 2 ; 4-D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Recent advances towards achieving significant nitrogen fixation by diazotrophs in symbioses with cereals are reviewed, referring to the literature on the evolution of effective symbioses involving rhizobia and Frankia as microsymbionts. Data indicating that strains of Acetobacter and Herbaspirillum colonizing specific cultivars of sugarcane as endophytes make a significant contribution to the nitrogen economy of this crop improves the prospects that similar associative systems may be developed for other gramineous species such as rice and wheat. By contrast, the transfer of nodulation genes similar to those in legumes or Parasponia to achieve nodulation in crops like rice and wheat is considered to be a more ambitious and distant goal. Progress in developing an effective associative system for cereals has been materially assisted by the development of genetic tools based on the application of lacZ and gusA fusions with the promoters of genes associated with nitrogen fixation. These reporter genes have provided clear evidence that ‘crack-entry’ at the points of emergence of lateral roots or of 2,4-D induced para-nodules is the most significant route of endophytic colonization. Furthermore, using the laboratory model of para-nodulated wheat, there is now evidence that the ability of azospirilla and other nitrogen fixing bacteria to colonize extensively as endophytes can be genetically controlled. The most successful strain of Azospirillum brasilense (Sp7-S) for endophytic colonization and nitrogen fixation in wheat seedlings is a mutant with reduced exopolysaccharide production. Most other strains of azospirilla do not colonize as endophytes and it is concluded that though these are poorly adapted to providing nitrogen for the host plant, they are well adapted for survival and persistence in soil. A research program combining the study of endophytic colonization by azospirilla with an examination of the factors controlling the effectiveness of association (oxygen tolerance and nitrogen transfer) is now being pursued. It is proposed that a process of facilitated evolution of para-nodulated wheat involving the stepwise genetic improvement of both the prospective microsymbionts and the cereal host will eventually lead to effective nitrogen-fixing associations. In the attempt to achieve this goal, continued study of the endophytes occurring naturally in sugar cane and other grasses (e.g. Azoarcus sp.) should be of assistance.
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  • 46
    ISSN: 1573-5060
    Keywords: dough quality ; electrophoresis ; endosperm storage protein ; genetics ; gluten strength ; near isogenic line ; Triticum aestivum ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two alleles, Glu-A1r encoding high-molecular-weight (HMW) glutenin subunits 39+40 and Glu-A1s encoding HMW glutenin subunits 41+42, were introgressed to bread wheat (Triticum aestivum L.) cv. Sicco from two accessions of T. boeoticum Boiss. ssp. thaoudar (A genome species, 2n=2x=14). Alleles at Glu-A1 in current commercial bread wheats encode zero or one subunit, and alleles at the homoeoloci Glu-B1 and Glu-D1 encode a maximum of two subunits; hence the maximum number of subunits found in commercial wheats is five, whereas the lines incorporating Glu-A1r and Glu-A1s carry six. Using near-isogenic lines, the current results demonstrated that the introduction of Glu-A1r resulted in diminished dough stickiness and improved stability during mixing compared with Glu-A1a encoding subunit 1, and a small improvement in gluten strength as shown by the SDS- sedimentation test. The introduction of Glu-A1a also resulted in a small improvement in gluten strength predicted by the SDS-sedimentation test. Thus the alleles are of potential value in breeding programmes designed to improve bread-making quality.
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  • 47
    ISSN: 1573-5060
    Keywords: somaclonal variation ; in vitro selection ; herbicides ; wheat ; triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The present work was initiated to assess tissue culture techniques as a means of generating and selecting herbicide tolerant genotypes of wheat through exploiting somaclonal variation. Callus was initiated from immature embryos of genetically defined varieties and subcultured onto selective media containing 5 μm, 10 μm and 50 μm concentrations of difenzoquat and atrazine. Plants were regenerated from all the selective media except that media containing the highest herbicide concentration. The progenies of the regenerated plants were tested as whole plants for their response to spray application of the herbicides. For difenzoquat, variation in response from extreme susceptibility to tolerance was observed. However, genetic characterization by progeny testing tolerant lines revealed that the induced variation was not heritable. No plants tolerant to atrazine were obtained. Overall, no clear evidence of heritable mutations was obtained. Alternative strategies to obtain herbicide tolerant genotypes using cell culture techniques are discussed.
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  • 48
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    Photosynthesis research 51 (1997), S. 179-184 
    ISSN: 1573-5079
    Keywords: chlorophyll fluorescence ; FACE ; global change ; photosynthesis ; Photosystem II ; quantum yield ; quenching analysis ; rising CO2 concentration ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rapid and irregular variations of atmospheric CO2 concentrations (ca) occur in nature but are often very much more pronounced and frequent when artificially enriching CO2 concentrations in simulating the future atmosphere. Therefore, there is the danger that plant responses at elevated CO2 in fumigation experiments might reflect the increased frequency and amplitude of fluctuation in concentration as well as the increase in average concentration. Tests were conducted to determine whether the photosynthetic process could sense such fluctuations in ca. Instantaneous chlorophyll fluorescence (Ft) was monitored for wheat leaves (Triticum aestivum cv. Hereward) exposed to ca oscillating symmetrically by 225 μmol mol-1 about a ca set point concentration of 575 or 650 μmol mol-1. No Ft response was detected to half-cycle step changes in ca lasting less than two seconds, but at half-cycles of two seconds or longer, the response of Ft was pronounced. In order to determine the in vivo linear electron transport rate (J) the O2 concentration was maintained at 21 mmol mol-1 to eliminate photorespiration. J which is directly proportional to the rate of CO2 uptake under these conditions, was not significantly changed at half-cycles of 30 s or less but was decreased by half-cycles of 60 s or longer. It was inferred that if duration of an oscillation is less than 1 minute and is symmetrical with respect to mean CO2 concentration, then there is no effect on current carbon uptake, but oscillations of 1 minute or more decrease photosynthetic CO2 uptake in wheat.
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  • 49
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    Plant molecular biology 35 (1997), S. 1037-1043 
    ISSN: 1573-5028
    Keywords: coactivators ; gene regulation ; plants ; TAFs ; transcription ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transcription regulation often activates quiescent genes in a tissue-specific or developmental manner. Activator proteins bind to a DNA sequence upstream of the promoter, interact with the general transcription proteins via bridging proteins, and elevate transcription levels. One group of bridging proteins, the coactivators, have been characterized in animals as polypeptides tightly associated with the general transcription factor TATA-binding protein (TBP). They are referred to as TAFs (TBP-associated factors), and together with TBP comprise general transcription factor IID. We provide biochemical evidence that wheat IID contains coactivators. An activator protein with an acidic activation domain facilitates the binding of IID to the template, and potentiates activated in vitro transcription with wheat IID, but not with wheat TBP. Using antibodies to wheat TBP, we demonstrate that wheat IID also contains TAFs. This is the first demonstration that a plant contains coactivators and TAFs.
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  • 50
    ISSN: 1573-2932
    Keywords: nickel ; lead ; other metals ; salt ; sewage sludge ; acidifying agent (wastewater from olive oil processing) ; soil ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A greenhouse experiment using soil was conducted to investigate the effects of the addition of different forms of either nickel or lead, together with an acidifying agent, on the distribution of Ni, Pb, Zn, Cu and Mn in wheat plants, and on the post-harvest extractability of these elements in the soil. Two treatments consisting of soil alone or soil mixed with sewage sludge at a rate of 200 Mg ha−1 were used as controls. Nickel (400 mg kg−1) or lead (1600 mg kg−1) was added to the soil as an inorganic salt or mixed previously with sewage sludge. Six further treatments including an acidifying agent (wastewater from olive oil processing: alpechin) were also prepared. Wheat (Triticum aestivum L. var. Mesa) plants were harvested 75 d after germination. Dry matter yield of wheat was increased by the addition of sewage sludge. No reductions in yield were observed after the addition of nickel or lead. Nickel concentration and uptake by wheat, and extractability from soil, were higher when the sewage sludge enriched in nickel was added to soil. This effect was enhanced when the acidifying agent was also added. In contrast, lead availability was higher after the addition of inorganic Pb to soil. The addition of both forms of Ni enhanced Zn, Cu and Mn uptake by the plant, whereas the addition of lead increased Zn and Cu. After harvesting, increases in extractable Zn and Cu in the soil were observed only in treatments with sewage sludge, and not after the addition of Ni or Pb, or after the addition of the acidifying agent. Decreasing the pH of the soil with the acidifying agent tended to increase Mn uptake by wheat, and Mn extractability from the soil after harvesting.
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  • 51
    ISSN: 1573-2932
    Keywords: nickel ; lead ; other metals ; salt ; sewage sludge ; acidifying agent (wastewater from olive oil processing) ; soil ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A greenhouse experiment using soil was conducted to investigate the effects of the addition of different forms of either nickel or lead, together with an acidifying agent, on the distribution of Ni, Pb, Zn, Cu and Mn in wheat plants, and on the post-harvest extractability of these elements in the soil. Two treatments consisting of soil alone or soil mixed with sewage sludge at a rate of 200 Mg ha−1 were used as controls. Nickel (400 mg kg−1) or lead (1600 mg kg−1) was added to the soil as an inorganic salt or mixed previously with sewage sludge. Six further treatments including an acidifying agent (wastewater from olive oil processing: alpechin) were also prepared. Wheat (Triticum aestivum L. var. Mesa) plants were harvested 75 d after germination. Dry matter yield of wheat was increased by the addition of sewage sludge. No reductions in yield were observed after the addition of nickel or lead. Nickel concentration and uptake by wheat, and extractability from soil, were higher when the sewage sludge enriched in nickel was added to soil. This effect was enhanced when the acidifying agent was also added. In contrast, lead availability was higher after the addition of inorganic Pb to soil. The addition of both forms of Ni enhanced Zn, Cu and Mn uptake by the plant, whereas the addition of lead increased Zn and Cu. After harvesting, increases in extractable Zn and Cu in the soil were observed only in treatments with sewage sludge, and not after the addition of Ni or Pb, or after the addition of the acidifying agent. Decreasing the pH of the soil with the acidifying agent tended to increase Mn uptake by wheat, and Mn extractability from the soil after harvesting.
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  • 52
    ISSN: 1573-0972
    Keywords: Flour ; mixotrophic productivity ; Phaeodactylum tricornutum ; potato ; rye ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The marine microalga Phaeodactylum tricornutum was cultured semi-continuously with the soluble fractions of wheat, rye and boiled potato flours. Fifteen percent of the culture volume was renewed every 3 d. The cell productivities were 0.9×109 cells/l/d, 1.1×109 cells/l/d and 2.6×109 cells/l/d for wheat, rye and potato respectively. The productivity of the autotrophic control was 1.0×109 cell/l/d. When a soluble fraction of raw potato was added, the productivity was enhanced to 4.1×109 cells/l/d, 2.4 times higher than the autotrophic culture. The high productivity of P. tricornutum with the soluble fractions of Solanum tuberosum suggests its usefulness as a source of nutrients for the production of microalgal biomass.
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  • 53
    ISSN: 1573-8469
    Keywords: barley ; freezing blotter test ; Fusarium head blight ; mycotoxin ; oats ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seven spring wheat, 13 barley, 14 oats and 20 winter wheat genotypes were inoculated at flowering in 1993 and 1994 with mixed conidial suspensions of 8 isolates of Fusarium culmorum. Four weeks after inoculation, head blight was recorded in the field. After harvest, seed infection was assessed by a Freezing Blotter Test in the laboratory. Seed samples were also analyzed for deoxynivalenol (DON) content. Differences were found in head blight rating, the levels of infected seeds and the DON content between wheat, barley, and oats and between cultivars. Highly significant correlations were found between the percentage of heavily infected seed and the DON content. The weighted mean value of infected seeds and DON content were also significantly correlated. No significant correlation was found between head blight rating in the field and DON content. The level of infected seeds, as determined by the Freezing Blotter Test, was a better indication of the DON content in the seeds than the head blight rating. This visual assessment of levels of infected seeds gives a reliable estimate of resistance to Fusarium.
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