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Abstract Background Wheat (Triticum aestivum L.) is a significant cereal crop that plays a vital role in global food production. To expedite the breeding of wheat cultivars with high protein quality, it is necessary to genetically analyze the traits related to quality. A genome-wide association study (GWAS) was conducted to identify the genomic regions responsible for protein quality traits in winter wheat. Results Six protein quality traits were evaluated across two locations and two years for a total of 341 wheat accessions. Utilizing the wheat 40 K SNP array, GWAS identified 97 significantly stable SNPs at 43 loci for five out of six protein quality traits using a linear mixed model. The 43 loci distribution was four for grain protein content, two for flour protein content, one for wet gluten content, four for gluten index, and thirty-two for Zeleny sedimentation value. The most significant associations were identified on chromosomes 1 A, 1B, and 1D. Haplotype analysis of loci associated with the gluten index in the 412–416 Mb interval on chromosome 1D identified three blocks. Accessions with superior haplotypes showed a significantly higher gluten index than those with inferior haplotypes. Six KASP markers were successfully developed for the gluten index, while five KASP markers were developed for the Zeleny sedimentation value. Additionally, eight candidate genes were identified that may affect protein accumulation during grain development. Conclusions Our study identified 97 SNPs significantly associated with protein quality traits; developed 6 KASP markers for gluten index, and 5 KASP markers for Zeleny sedimentation values; screened 8 candidate genes that may be related to protein quality during grain development. Thise research will offer valuable insights for wheat breeding programs in China and globally.

Abstract Starch is the main component of wheat (Triticum aestivum L.) flour, and its quality directly affects the processing quality of the final product. To investigate the genetic basis of starch, this study assessed the starch quality traits of 341 winter wheat varieties/lines grown in Emin and Qitai during the years 2019–2020 and 2020–2021. A genome‐wide association study was conducted with the genotype data obtained from wheat 40K breeding chips using the mixed linear model. Wheat starch quality traits exhibited coefficients of variation ranging from 1.43% to 23.66% and broad‐sense heritabilities between 0.37 and 0.87. All traits followed an approximately normal distribution, except for T. There were highly significant correlations among starch quality traits, with the strongest correlation observed between final viscosity (FV) and trough viscosity (TV) (r = 0.748), followed by peak viscosity and breakdown (BD) (r = 0.679). Thirty‐four single‐nucleotide polymorphism markers significantly and stably associated with starch quality traits were identified, clustering in 31 genetic loci. These included one locus for TV, six loci for BD, three loci for FV, two loci for peak time (PT), 12 loci for T, five loci for falling number, and two loci for damaged starch. One PT‐related block of 410 kb was identified in the region of 596 Mb on chromosome 5A, where significant phenotypic differences were observed between different haplotypes. One Kompetitive allele‐specific PCR (KASP) marker for T was developed on chromosome 7B, and two KASP markers for BD were developed on chromosome 7A. Four candidate genes possibly affecting BD during grain development were identified on chromosome 7A, including TraesCS7A02G225100.1, TraesCS7A02G225900.1, TraesCS7A02G226400.1, and TraesCS7A02G257100.1. The results have significant implications for utilizing marker‐assisted selection in breeding to improve wheat starch quality.

In order to understand the difference of quality for Chinese and CIMMYT wheat varieties (lines), we selected 153 wheat germplasm from both China and CIMMYT to explore the contribution relationship of different allelic variation combinations to wheat quality through genotyping and phenotyping, including grain hardness, polyphenol oxidase (PPO) activity, lipoxygenase (LOX) activity, yellow pigment (YP) content and protein content. In terms of flour milling quality, Chinese wheat varieties were mainly carrying Pina-D1a/Pinb-D1b, accounting for 32.0% of the total tested varieties, while the CIMMYT wheat lines were mainly carrying Pina-D1b/Pinb-D1a with 45.8% of the total collection. The distribution frequencies of subunit 1/2* and 5 + 10 were 47.0% and 42.5%, respectively, in CIMMYT varieties, however they were only 31.4% and 13.7% respectively of the Chinese wheat tested varieties. In addition, the proportion of phytoene synthase (PSY) allele, PPO allele and LOX active allele were roughly the same between Chinese and CIMMYT varieties. Based on the present study, we found that Pina gene had a greater impact on grain hardness value than Pinb gene; The influence of PPO-A1 gene on polyphenol oxidase activity was more significant than PPO-D1 gene. The high protein content of varieties mostly containing hardness genes and 1/2*/5 + 10 subunit combinations. Based on the present study, we found that the quality gene distribution of Chinese and CIMMYT varieties was quite different, for instance, the high-quality HMW-GS subunits of Chinese varieties were lower than CIMMYT lines. It will be much useful for Chinese wheat breeders to develop good quality wheat variety by crossing with 3 good strong gluten CIMMYT wheat lines by molecular marker-assisted selection.

Wheat (Triticum aestivum L.) is one of the important grain crops that fulfill global food security requirements. Understanding the genetic basis of wheat yield and related traits is crucial for increasing yield through marker-assisted selection (MAS). In this study, a phenotypic analysis was conducted on the yield and related traits of 192 Chinese spring wheat genotypes in six field environments. Based on the 90K wheat SNP iSelect assay, a genome-wide association study (GWAS) identified 84 stable and significantly associated signals at 50 loci for 8 out of the 10 analyzed traits. These traits included grain yield (1), plant height (6), spike length (21), productive spikelet rate (12), kernel number per spikelet (1), kernel number per main spike (2), thousand kernel weight (5), and test weight (2). Seventy-one stable SNP markers were mapped to annotated genes, with 51 of them located in the coding sequences (CDSs) of 47 explanatory genes. Haplotype analysis revealed three blocks on chromosome 5A and two blocks on chromosome 5D associated with plant height (PH). Varieties with different haplotypes at these loci displayed a significant difference in plant height. The performance of traits was improved by increasing the number of superior alleles for productive spikelet rate and spike length. These results provided prospective alleles for controlling yield and yield composition in wheat breeding. These alleles could be used for marker-assisted selection to improve wheat yield.

In order to understand the genetic basis of starch pasting viscosity characteristics of Chinese spring wheat, we assessed the genetic variation of RVA parameters determined by the Rapid Visco Analyser in a panel of 192 Chinese spring wheat accessions grown in Er’shi, Shihezi and Zhaosu during 2012 and 2013 cropping seasons. A genome-wide association study with 47,362 single nucleotide polymorphism (SNP) markers was conducted to detect marker-trait associations using mixed linear model. Phenotypic variations of RVA parameters ranged from 1.6 to 30.7% and broad-sense heritabilities ranged from 0.62 to 0.91. Forty-one SNP markers at 25 loci were significantly associated with seven RVA traits in at least two environments; among these, 20 SNPs were located in coding sequences (CDS) of 18 annotation genes, which can lead to discovering novel genes underpinning starch gelatinization in spring wheat. Haplotype analysis revealed one block for breakdown (BD) on chromosome 3B and two blocks for pasting temperature (T) on chromosome 7B. Cultivars with superior haplotypes at these loci showed better starch pasting viscosity than the average of all cultivars surveyed. The identified loci and associated markers provide valuable sources for future functional characterization and genetic improvement of starch quality in wheat.

Wheat powdery mildew and stripe rust are the major diseases in wheat producing area in Xinjiang. To obtain wheat germplasm resources and varieties resistant to powdery' mildew and rust, 36 high-generation stable strains of Xinjiang winter wheat were evaluated using the method of natural inducement from 2018 to 2020. A total of 5 strains with high resistance to powdery mildew, 4 strains with slow stripe rust and 1 strain with resistance to powdery mildew and adult plant slow stripe rust were obtained. And the parental combination of disease-resistant varieties was analyzed. These studies will provide theoretical basis for the breeding of resistant wheat varieties in Xinjiang. [ABSTRACT FROM AUTHOR]