Presence of celiac disease epitopes in modern and old hexaploid wheat varieties: wheat breeding may have contributed to increased prevalence of celiac disease

After nearly 40 years of DNA molecular marker development in plant breeding, the wheat research community has amassed an extensive collection of molecular markers which have been widely and successfully used for selection of agronomic, physiological and disease resistance traits in wheat breeding programs. Tan spot is a major fungal disease of wheat and a significant global economic challenge and is caused by the necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr). Here, the potential for using a PCR-based marker (Ta1AS3422) present on the short arm of wheat chromosome 1A, was evaluated for effectiveness in distinguishing tan spot disease susceptibility. The marker was initially screened against 40 commercial Australian hexaploid wheat varieties, and those that amplified the marker had an overall lower disease score (2.8 ± 0.7 for seedlings and 2.4 ± 0.4 for plants at the tillering stage), compared to those lacking the marker which exhibited a higher disease score (3.6 ± 0.8 for both growth stages). The potential of Ta1AS3422 as a marker for the tan spot disease response was further assessed against a panel of 100 commercial Australian hexaploid wheat varieties. A significant association was observed between marker absence/presence and tan spot disease rating (Pearson’s chi-squared test, χ2 (6) = 20.53, p = 0.002), with absence of Ta1AS3422 associated with susceptibility. This simple and cost-effective PCR-based marker may be useful for varietal improvement against tan spot, although further work is required to validate its effectiveness.

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Hybrid necrosis as a problem in handling hexaploid × tetraploid wheat crosses

The Journal of Agricultural Science ◽

10.1017/s0021859600028987 ◽

1980 ◽

Vol 94 (2) ◽

pp. 377-382 ◽

Cited By ~ 6

Author(s):

R. S. Gregory

Keyword(s):

Hexaploid Wheat ◽

Tetraploid Wheat ◽

Wheat Breeding ◽

Small Scale ◽

Hybrid Necrosis ◽

Agronomic Characters ◽

Wheat Varieties ◽

Hybrid Plants ◽

Plant Breeding Institute ◽

Selection For

SummaryA tetraploid wheat breeding programme was initiated at the Plant Breeding Institute in 1970. Hexaploid × tetraploid wheat crosses were expected to contribute to the improvement of the tetraploid wheats but severe hybrid necrosis caused the death of the pentaploid Fxhybrid plants in most crosses. The genotypes of tetraploid wheat selections derived from crosses involving Rampton Rivet, a non-carrier of Neu were determined by test crossing to hexaploid wheat varieties which were known to carry the Neim allele. Similarly, hexaploid wheat selections which did not carry Ne2 were identified from crosses involving Maris Ranger by test crossing to durum selections which carried the Nef allele. By the careful choice of one parent, hexaploid x tetraploid wheat crosses were then made which avoided the hybrid necrosis problem. Segregation of the Ne% gene was as expected but selection for agronomic characters appeared to favour the retention of the dominant allele of the Ne1gene. Nevertheless, test crossing on a relatively small scale still identified many non-carriers.

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SSR analysis of the genomic DNA of perspective Uzbek hexaploid winter wheat varieties

Vavilov Journal of Genetics and Breeding ◽

10.18699/vj18.404 ◽

2018 ◽

Vol 22 (6) ◽

pp. 634-639

Author(s):

A. T. Adylova ◽

G. K. Norbekov ◽

E. E. Khurshut ◽

E. V. Nikitina ◽

F. N. Kushanov

Keyword(s):

Microsatellite Loci ◽

Hexaploid Wheat ◽

Wheat Variety ◽

Wheat Breeding ◽

Wheat Varieties ◽

Local Conditions ◽

Microsatellite Primer ◽

Ssr Analysis ◽

The Mean ◽

The Individual

The objective of this study was to investigate the genetic diversity of hexaploid wheat varieties of Uzbekistan breeding using simple sequence repeat (SSR) markers. These varieties are adapted to local conditions, and can be considered as the most important supplier of genetic resources for cultivation in Uzbekistan and other countries. Microsatellite markers are now most widely used and effective classes of DNA markers for genotyping, certification and classification of plant varieties. In this paper, genotyping results of 32 hexaploid wheat domestic varieties using 144 microsatellite primer pairs are presented. Microsatellite primer pairs were chosen from literature data and 36 primer pairs (from 144) gave polymorphic well-reproducible PCR-fragments. The individual SSR spectra differing in number of amplicons were obtained for each variety. A total number of 141 alleles for 36 microsatellite loci were detected. The number of alleles per locus ranged from 2 to 6, the mean number of alleles per locus (Na) was 3 alleles. For the studied genotypes group the effective number of alleles (ne) characterizing the loci by the allele frequency, varied from 1.7 to 4.8, the mean number of alleles per locus was 2.8. The expected heterozygosity (He) ranged from 0 to 0.792, averaging 0.626, in studied wheat population. The amplified fragment sizes ranged from 93 to 552 bp. The polymorphic index content (PIC) ranged from 0 to 0.758. A dendrogram was constructed using the alleles set of microsatellite loci, reflecting the phylogenetic differences of the studied hexaploid wheat varieties. It showed that Uzbekistan breeding varieties are divided into two main clusters, which may be evidence of their common origin. A genetic formula has been developed for each Uzbek wheat variety. It can be used for identification, certification of these varieties, as well as for the selection of parental pairs in the wheat breeding programs.

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Unveiling the genetic divergence and phenotypic association in elite Pakistani wheat (Triticum aestivum L.) genotypes

Abasyn Journal Life Sciences ◽

10.34091/ajls.4.1.14 ◽

2021 ◽

pp. 119-126

Author(s):

Naila Gandahi ◽

Abdul Wahid Baloch ◽

Mir Yar Muhammad Khan Talpur ◽

Nasreen Fatima ◽

Tanweer Fatah Abro ◽

...

Keyword(s):

Genetic Distance ◽

Bread Wheat ◽

Hexaploid Wheat ◽

Genetic Divergence ◽

Block Design ◽

Triticum Aestivum L ◽

Wheat Breeding ◽

Phenotypic Correlation ◽

Wheat Varieties ◽

Wheat Genotypes

The present study was designed to assess genetic divergence between commercial bread wheat genotypes based on yield and its related traits and to carry out phenotypic correlation. Twenty bread hexaploid wheat varieties were assessed for mean performance, correlation analysis and genetic distance. Randomized complete block design was used with three replications during growing season, 2018-2019 at Wheat and Barley Research Institute, Tandojam. The mean squares depicted significant differences (P<0.01) for all the investigated traits among the tested genotypes, proving that used genetic resources possess a great potential for further breeding experiments. Regarding mean performance, the genotypes Sassui and TD-1 displayed desirable performance for a variety of traits, unveiling their importance in wheat breeding programs. The results also showed that tillers plant-1, grains spike-1 and seed index developed significantly positive (P<0.05) interrelationship with grain yield plant-1. This demonstrates that genotypes possessing higher extent of these traits may be chosen in selection for developing high yielding bread wheat genotypes. The larger genetic distance was witnessed between Johar-78 and TD-1, followed by SKD-1 and TJ-83, SKD-1 and Mehran-89, SKD-1 and Johar-78, TD-1 and Khirman, TJ-83 and Imdad-05, Mehran-89 and TD-1 and Johar-78 and TJ-83. These paired showed wide genetic distances, which may also be preferred in wheat hybridization program. Keywords: Genetic distance, hexaploid wheat, morphological traits, trait

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Morphological and Physiological Root Traits and Their Relationship with Nitrogen Uptake in Wheat Varieties Released from 1915 to 2013

Agronomy ◽

10.3390/agronomy11061149 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1149

Author(s):

Guglielmo Puccio ◽

Rosolino Ingraffia ◽

Dario Giambalvo ◽

Gaetano Amato ◽

Alfonso S. Frenda

Keyword(s):

Durum Wheat ◽

Root System ◽

N Uptake ◽

Specific Root Length ◽

Root Traits ◽

Wheat Breeding ◽

N Availability ◽

Wheat Varieties ◽

Uptake Efficiency ◽

Positive Effects

Identifying genotypes with a greater ability to absorb nitrogen (N) may be important to reducing N loss in the environment and improving the sustainability of agricultural systems. This study extends the knowledge of variability among wheat genotypes in terms of morphological or physiological root traits, N uptake under conditions of low soil N availability, and in the amount and rapidity of the use of N supplied with fertilizer. Nine genotypes of durum wheat were chosen for their different morpho-phenological characteristics and year of their release. The isotopic tracer 15N was used to measure the fertilizer N uptake efficiency. The results show that durum wheat breeding did not have univocal effects on the characteristics of the root system (weight, length, specific root length, etc.) or N uptake capacity. The differences in N uptake among the studied genotypes when grown in conditions of low N availability appear to be related more to differences in uptake efficiency per unit of weight and length of the root system than to differences in the morphological root traits. The differences among the genotypes in the speed and the ability to take advantage of the greater N availability, determined by N fertilization, appear to a certain extent to be related to the development of the root system and the photosynthesizing area. This study highlights some variability within the species in terms of the development, distribution, and efficiency of the root system, which suggests that there may be sufficient grounds for improving these traits with positive effects in terms of adaptability to difficult environments and resilience to climate change.

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Unravelling the hidden inter and intra-varietal diversity of durum wheat commercial varieties used in Portugal

Plant Genetic Resources ◽

10.1017/s1479262119000133 ◽

2019 ◽

Vol 17 (04) ◽

pp. 386-389

Author(s):

Miguel Bento ◽

Sónia Gomes Pereira ◽

Wanda Viegas ◽

Manuela Silva

Keyword(s):

Durum Wheat ◽

Repetitive Sequences ◽

Inter Simple Sequence Repeat ◽

Wheat Breeding ◽

Genomic Diversity ◽

Varietal Diversity ◽

Wheat Varieties ◽

Coding Sequences ◽

Coding Regions ◽

High Level

AbstractAssessing durum wheat genomic diversity is crucial in a changing environmental particularly in the Mediterranean region where it is largely used to produce pasta. Durum wheat varieties cultivated in Portugal and previously assessed regarding thermotolerance ability were screened for the variability of coding sequences associated with technological traits and repetitive sequences. As expected, reduced variability was observed regarding low molecular weight glutenin subunits (LMW-GS) but a specific LMW-GS allelic form associated with improved pasta-making characteristics was absent in one variety. Contrastingly, molecular markers targeting repetitive elements like microsatellites and retrotransposons – Inter Simple Sequence Repeat (ISSR) and Inter Retrotransposons Amplified Polymorphism (IRAP) – disclosed significant inter and intra-varietal diversity. This high level of polymorphism was revealed by the 20 distinct ISSR/IRAP concatenated profiles observed among the 23 individuals analysed. Interestingly, median joining networks and PCoA analysis grouped individuals of the same variety and clustered varieties accordingly with geographical origin. Globally, this work demonstrates that durum wheat breeding strategies induced selection pressure for some relevant coding sequences while maintaining high levels of genomic variability in non-coding regions enriched in repetitive sequences.

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A comparison of some small-scale tests for bread-making quality used in wheat breeding

The Journal of Agricultural Science ◽

10.1017/s0021859600029221 ◽

1980 ◽

Vol 95 (1) ◽

pp. 29-34 ◽

Cited By ~ 21

Author(s):

J. A. Blackman ◽

A. A. Gill

Keyword(s):

Protein Quality ◽

Small Sample Size ◽

Sodium Dodecyl ◽

Wheat Breeding ◽

Small Sample ◽

Small Scale ◽

Loaf Volume ◽

Bread Making ◽

Wheat Varieties ◽

Sedimentation Volume

SummaryTwenty-five winter wheat varieties and breeders' lines including hard and soft texture, good or poor bread and biscuit-making types were grown at two locations in the U.K. in 1977 to provide the test samples. Small-scale tests of bread-making quality including extensometer, sodium dodecyl sulphate (SDS) sedimentation volume, residue protein, urea dispersible protein and Pelshenke tests, were compared with loaf volumes and loaf scores.Averaged over the two sites, a modified extensometer test and the SDS test gave the closest correlation with loaf volume and loaf score and were only poorly correlated with Hagberg Falling Number and percentage protein. The SDS test gave the closest correlation between sites followed by the extensometer readings; loaf volume and score had much lower values. The SDS values and extensometer readings give a better measure of the genetic differences in protein quality of varieties than loaf volume and score, being less affected by growing conditions. With its small sample size and high throughput, the SDS sedimentation volume is likely to be the most useful screening test for wheat breeding programmes.

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Population structure of Chinese southwest wheat germplasms resistant to stripe rust and powdery mildew using the DArT-seq technique

Ciência Rural ◽

10.1590/0103-8478cr20160066 ◽

2018 ◽

Vol 48 (4) ◽

Cited By ~ 3

Author(s):

Tianqing Chen ◽

Piyada Alisha Tantasawat ◽

Wei Wang ◽

Xu Gao ◽

Liyi Zhang

Keyword(s):

Population Structure ◽

Disease Resistance ◽

Polymorphic Information Content ◽

Wheat Breeding ◽

Wheat Varieties ◽

Group I ◽

Population Structure Analysis ◽

Specific Allele ◽

The Mean ◽

Different Origins

ABSTRACT: Understanding genetic variability in existing wheat accessions is critical for collection, conservation and use of wheat germplasms. In this study, 138 Chinese southwest wheat accessions were investigated by genotyping using two resistance gene makers (Pm21 and Yr26) and DArT-seq technique. Finally, about 50% cultivars (lines) amplified the specific allele for the Yr26 gene (Gwm11) and 40.6% for the Pm21 gene (SCAR1265). By DArT-seq analysis, 30,485 markers (6486 SNPs and 23999 DArTs) were obtained with mean polymorphic information content (PIC) value 0.33 and 0.28 for DArT and SNP marker, respectively. The mean Dice genetic similarity coefficient (GS) was 0.72. Two consistent groups of wheat varieties were identified using principal coordinate analysis (PCoA) at the level of both the chromosome 6AS and the whole-genome, respectively. Group I was composed of non-6VS/6AL translocation lines of different origins, while Group II was composed of 6VS/6AL translocation (T6VS/6AL) lines, most of which carried the Yr26 and Pm21 genes and originated from Guizhou. Besides, a model-based population structure analysis revealed extensive admixture and further divided these wheat accessions into six subgroups (SG1, SG2, SG3, SG4, SG5 and SG6), based on their origin, pedigree or disease resistance. This information is useful for wheat breeding in southwestern China and association mapping for disease resistance using these wheat germplasms in future.

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Science and the Green Revolution 1945-1975

Geopolitics and the Green Revolution ◽

10.1093/oso/9780195110135.003.0013 ◽

1998 ◽

Author(s):

John H. Perkins

Keyword(s):

World War Ii ◽

Soil Fertility ◽

Plant Breeding ◽

Fungal Pathogens ◽

Plant Disease ◽

Green Revolution ◽

Wheat Breeding ◽

Wheat Varieties ◽

Number Of Factors ◽

Major Factors

In the years after the end of World War II, farmers, agricultural scientists, and policy makers in many countries all knew, or learned, that higher yields of wheat were what they wanted, and they were successful in achieving them. Their specific motivations were different, but their objectives were not. Not only were the objectives clear, but a central method by which the higher yields were to be achieved was plant breeding. Plant breeding itself was an applied science that had to be nested within organizations that supported it and its allies in the agricultural, biological, and engineering sciences. By 1950 wheat breeders believed that the number of factors governing yield was small, which meant that the research avenues likely to be fruitful were also few in number. The amount of water available and the responsiveness to soil fertility, especially nitrogen, were in most cases the key ingredients for higher yields. For wheat, the ability of the plant to resist invasion by fungal pathogens was almost as important as water and soil fertility. Water and fertility were needed in every crop year, but damage from fungal pathogens varied with weather. Thus plant disease was not necessarily a destructive factor every year. Control of water, soil fertility, and plant disease was therefore at the center of research programs in wheat breeding. A wheat breeder would find success if his or her program produced new varieties that gave higher yields within the context of water, soil fertility, and plant disease existing in the area. Ancillary questions also existed and in some cases matched the major factors in importance. Weed control was always a problem, so high-yielding wheat had to have some capacity to resist competition from weeds. Similarly, in some areas and some years, insects could cause damage. Wheat varieties therefore had to be able to withstand them somehow. Other factors of importance to wheat breeders were habit of growth and the color and quality of the grain. Winter wheats were useful in climates that had winters mild enough to allow planting in the fall and thus higher yields the next summer.

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