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This study explored the impact of nitrogen (N) application on yield and breadmaking as well as arabinoxylan (AX) content of wheat varieties Zhongmai 578 and Jimai 22 across varied environments, aiming to optimize N levels for improved outcomes. Significant N effects were observed on yield, flour properties, and breadmaking quality traits. Both varieties displayed high yield potential and stability, with Zhongmai 578 excelling in thousand kernel weight and Jimai 22 in spike number. Optimal N rates varied by location, with some achieving peak yields at reduced N levels. Processing traits like dough properties and bread‐making quality were influenced by E × N interactions. Arabinoxylans profiles was not affected by different N input. Customizing N applications to specific environment is critical for maximizing wheat yield potential and quality. Environmental considerations are integral for achieving desired processing traits and yield, highlighting the need for tailored N strategies in wheat cultivation. This study emphasizes the importance of site‐specific optimization of N levels for enhanced yield and processing quality. It offers novel insights into site‐specific N management, showcasing its relevance in modern agricultural practices for sustainable crop production.

Plant breeding has been successful in adapting crops worldwide with one of the latest challenges being adaption to warmer days and nights. Taking wheat as a case study, here we show current elite nurseries express a range of levels of heat adaptation. Generally, the higher the selection ratio for yield response under warming, the less stable the yield response across environments. Specifically, less than one-third of genotypes trialled adapted well to the 0.26 °C warming of the last decade, and the phenotypes were stable in only 26% of environments. With continued warming, selection ratio falls 8.5% and stability falls 8.7% for each 1 °C increase in local temperature. Overall, faced with more climate variability, breeders need to revisit their breeding strategies to integrate genetic diversity that confers climate resilience without penalties to productivity in favourable seasons.

Some haplotypes of the sucrose synthase gene TaSus1are associated with thousand-grain weight (TGW) in wheat (Triticum aestivumL.). However, no mutations have been identified within the gene to test this association. The effects of TaSus1on grain number per spike (GNS) also are largely unknown. Our previous genome-wide association study identified TaSus-A1as a candidate gene controlling fertile spikelet number per spike (FSN). In the present study, we generated two independent mutants for the three TaSus1homoeologs by CRISPR/Cas9-mediated genome editing. The triple mutants displayed lower FSN, GNS, grain number per spikelet (GNST), and TGW than wild-type plants. In 306 hexaploid wheat accessions, two single-nucleotide polymorphisms in TaSus-A1contributed differently to GNS. Introgression of the two alleles into a wheat genetic background confirmed their effects. The alleles differed in geographical distribution among the accessions.

Grain hardness is an important end-use quality trait which can significantly affect milling and processing quality of wheat. It is controlled by Puroindoline (Pin) genes in wheat, of which Pina-D1and Pinb-D1control major phenotypic variation, while Pinb-B2explain moderate variation. We analyzed the allelic variation of three Pingenes in a panel of 227 synthetic hexaploid wheats (SHWs) using allele-specific markers either previously available or newly developed in this study to identify new alleles and facilitate their introgression. Eight different alleles were identified in Pina-D1gene using six newly developed markers. The wild-type alleles, Pina-D1aand Pinb-D1a, were identified in 11.6 and 24.2% of accessions, respectively. It was found that Pina-D1cwas most frequent (30.7%), followed by Pina-D1eallele (18%) at Pina-D1. For Pinb-D1, three new markers were developed which classified synthetic wheats into four haplotype groups, of which Hap-IV (Pinb-D1j/Pinb-D1o) was most frequent (52.8%). A cleaved amplified polymorphic site (CAPS) marker using ApoIrestriction enzyme successfully classified accessions into wild-type and non-wild-type groups. At Pinb-B2gene, the frequency of Pinb-B2ballele was higher (76.2%) which is associated with relatively hard texture compared to Pinb-B2aallele. The results provide a deeper insight into the allelic composition of grain of grain texture genes in SHWs which can be introgressed to develop required texture market class using allele-specific markers developed in this study.

Sustainable wheat production is challenged by climate change events such as drought, salinity, and heat stress. Senescence is a gradual programmed cell death trait occurring post anthesis in wheat (Triticum aestivum), with significant affecting stability of yield and quality‐related traits under climate severities. Phenotyping of complex traits is increasingly perceived as a bottleneck due to elevated labor costs and time in large field conditions. Unmanned aerial vehicle (UAV)‐based platforms using RGB imagery and ground phenotyping–based novel traits can facilitate the repeated nondestructive measurements of crop canopy traits cost‐effectively. Here, we described combined application of UAV‐based RGB imaging and ground measurements based novel trait to quantify canopy senescence in wheat. We reported senescence related traits with high heritability in a recombinant inbred line population derived from the cross Zhongmai 175/Lunxuan 987. Our results showed that the selection of slow senescence genotypes using UAV‐based vegetation indices (VIs) was equally effective as ground‐based traits and illustrated significant variations among the genotypes. We also identified five quantitative trait loci (QTL) for canopy senescence in both UAV and ground‐based datasets using a 50K single‐nucleotide polymorphism array. QTL for UAV‐based VIs from RGB imaging and ground measurements based traits were mapped on chromosomes 1B, 2B, 3A, and 4B. The integration of both datasets with genetic analysis identified an important slow senescence/stay‐green related locus on chromosome 4B that explained phenotypic variation up to 23.07% for both UAV and ground traits at late grain‐ filling stage. Three QTL (QTL‐caas.1B, QTL‐caas.3A, and QTL‐caas.4B2) on chromosomes 1B, 3A, and 4B were also validated for slow senescence with high chlorophyll level and cool canopy temperature in a natural population of 160 lines by developing kompetitive allele‐specific PCR markers. QTL‐caas.4B1was validated not only for senescence but also for plant height. Our findings suggest that UAV‐based RGB imagery is advantageous for precise and rapid assessment of senescence related traits and genetic studies of senescence in wheat. Unmanned aerial vehicle (UAV)‐based phenotyping platforms using RGB imagery can facilitate the repeated nondestructive measurements of canopy greenness and senescence cost‐effectively.We have integrated vegetation indices derived from UAV‐based RGB pixels and ground measurements with quantitative genetic analysis to identify loci controlling canopy senescence in wheat.We have developed kompetitive allele‐specific PCR (KASP) markers based on identified loci that contribute to variations in wheat senescence.

Powdery mildew is a very destructive disease that threatens yield and quality of wheat. In the present study, 262 recombinant inbred lines derived from a cross between Zhongmai 578 (ZM578) with moderate resistance to powdery mildew and Jimai 22 (JM22) with high resistance to powdery mildew in the field were used to map powdery mildew resistance loci using the high‐density Illumina iSelect 50K single‐nucleotide polymorphism array. Three quantitative trait loci (QTLs) on chromosomes 2B, 5B, and 5D were identified by inclusive composite interval mapping, designated as QPm.caas‐2BL.1, QPm.caas‐5BL, and QPm.caas‐5DL, respectively, explaining 5.0%–37.0% of the phenotypic variances. The resistance allele of QPm.caas‐5BLwas contributed by ZM578, whereas alleles of QPm.caas‐2BL.1and QPm.caas‐5DLwere from JM22. QPm.caas‐2BL.1, detected in all the six experimental environments, was a major and stable QTL. QPm.caas‐5DLwas detected in five of the six environments and is likely to be a new QTL for powdery mildew resistance. The kompetitive allele‐specific PCR (KASP) markers Kpm‐2BLand Kpm‐5DLfor QPm.caas‐2BL.1and QPm.caas‐5DL, respectively, were validated in a diverse panel of 287 cultivars. These KASP markers, tightly linked with the QTLs, can be used for marker‐assisted breeding targeting the improvement of powdery mildew resistance in wheat. Three major quantitative trait loci (QTLs) for powdery mildew resistance were identified in the Zhongmai 578/Jimai 22 population.QPm.caas‐5DLis likely a new QTL, with the resistance allele from Jimai 22.Two kompetitive allele‐specific PCR (KASP) markers for QPm.caas‐2BL.1and QPm.caas‐5DLwere validated in a panel of 287 wheat cultivars.

Pre-harvest sprouting (PHS) is one of the serious global issues in wheat production. Identification of quantitative trait loci (QTL) and closely-linked markers is greatly helpful for wheat improvement. In the present study, a recombinant inbred line (RIL) population derived from the cross of Zhongmai 578 (ZM578)/Jimai 22 (JM22) and parents were phenotyped in five environments and genotyped by the wheat 50 K single-nucleotide polymorphism (SNP) array. Two QTL of germination index (GI), QGI.caas-3Aand QGI.caas-5A, were detected, explaining 4.33%–5.58% and 4.43%–8.02% of the phenotypic variances, respectively. The resistant effect of QGI.caas-3Awas contributed by JM22, whereas that of QGI.caas.5Awas from ZM578. The two QTL did not correspond to any previously identified genes or genetic loci for PHS-related traits according to their locations in the Chinese Spring reference genome, indicating that they are likely to be new loci for PHS resistance. Four kompetitive allele-specific PCR (KASP) markers K_AX-109605367and K_AX-179559687 flanking QGI.caas-3A, and K_AX-111258240 and K_AX-109402944 flanking QGI.caas-5A, were developed and validated in a natural population of 100 wheat cultivars. The distribution frequency of resistance alleles at Qphs.caas-3Aand Qphs.caas-5Aloci were 82.7% and 57.1%, respectively, in the natural population. These findings provide new QTL and tightly linked KASP markers for improvement of PHS resistance in wheat.

Grain weight and grain number are important yield component traits in wheat and identification of underlying genetic loci is helpful for improving yield. Here, we identified eight stable quantitative trait loci (QTL) for yield component traits, including five loci for thousand grain weight (TGW) and three for grain number per spike (GNS) in a recombinant inbred line population derived from cross Yangxiaomai/Zhongyou 9507 across four environments. Since grain size is a major determinant of grain weight, we also mapped QTL for grain length (GL) and grain width (GW). QTGW.caas-2D, QTGW.caas-3B, QTGW.caas-5Aand QTGW.caas-7A.2for TGW co-located with those for grain size. QTGW.caas-2Dalso had a consistent genetic position with QGNS.caas-2D, suggesting that the pleiotropic locus is a modulator of trade-off effect between TGW and GNS. Sequencing and linkage mapping showed that TaGL3-5Aand WAPO-A1were candidate genes of QTGW.caas-5Aand QTGW.caas-7A.2, respectively.We developed Kompetitive allele specific PCR (KASP) markers linked with the stable QTL for yield component traits and validated their genetic effects in a diverse panel of wheat cultivars from the Huang-Huai River Valley region. KASP-based genotyping analysis further revealed that the superior alleles of all stable QTL for TGW but not GNS were subject to positive selection, indicating that yield improvement in the region largely depends on increased TGW. Comparative analyses with previous studies showed that most of the QTL could be detected in different genetic backgrounds, and QTGW.caas-7A.1is likely a new QTL. These findings provide not only valuable genetic information for yield improvement but also useful tools for marker-assisted selection.

Spike number (SN) per unit area is one of the major determinants of grain yield in wheat. Development of high-throughput techniques to count SN from large populations enables rapid and cost-effective selection and facilitates genetic studies. In the present study, we used a deep-learning algorithm, i.e., Faster Region-based Convolutional Neural Networks (Faster R-CNN) on Red-Green-Blue (RGB) images to explore the possibility of image-based detection of SN and its application to identify the loci underlying SN. A doubled haploid population of 101 lines derived from the Yangmai 16/Zhongmai 895 cross was grown at two sites for SN phenotyping and genotyped using the high-density wheat 660K SNP array. Analysis of manual spike number (MSN) in the field, image-based spike number (ISN), and verification of spike number (VSN) by Faster R-CNN revealed significant variation (P < 0.001) among genotypes, with high heritability ranged from 0.71 to 0.96. The coefficients of determination (R2) between ISN and VSN was 0.83, which was higher than that between ISN and MSN (R2 = 0.51), and between VSN and MSN (R2 = 0.50). Results showed that VSN data can effectively predict wheat spikes with an average accuracy of 86.7% when validated using MSN data. Three QTL Qsnyz.caas-4DS, Qsnyz.caas-7DS, and QSnyz.caas-7DLwere identified based on MSN, ISN and VSN data, while QSnyz.caas-7DSwas detected in all the three data sets. These results indicate that using Faster R-CNN model for image-based identification of SN per unit area is a precise and rapid phenotyping method, which can be used for genetic studies of SN in wheat.

Bread wheat (Triticum aestivumL.) is a major crop that feeds 40% of the world’s population. Over the past several decades, advances in genomics have led to tremendous achievements in understanding the origin and domestication of wheat, and the genetic basis of agronomically important traits, which promote the breeding of elite varieties. In this review, we focus on progress that has been made in genomic research and genetic improvement of traits such as grain yield, end-use traits, flowering regulation, nutrient use efficiency, and biotic and abiotic stress responses, and various breeding strategies that contributed mainly by Chinese scientists. Functional genomic research in wheat is entering a new era with the availability of multiple reference wheat genome assemblies and the development of cutting-edge technologies such as precise genome editing tools, high-throughput phenotyping platforms, sequencing-based cloning strategies, high-efficiency genetic transformation systems, and speed-breeding facilities. These insights will further extend our understanding of the molecular mechanisms and regulatory networks underlying agronomic traits and facilitate the breeding process, ultimately contributing to more sustainable agriculture in China and throughout the world.

It is important to understand the genetic gain achieved through selection of key yield traits for planning future breeding strategies in developing high yielding wheat (Triticum aestivumL.) cultivars. The aim of this study was to characterize the genetic changes and genotype × environment (G×E) interaction by additive main effect and multiplicative interactions (AMMI) for morphological, physiological, and yield component traits under five environments using 24 wheat cultivars released from 1911 to 2016 in Pakistan. There was a significant increase in grain yield (9.03 kg ha−1yr−1, 0.37%), and plant height was reduced linearly (−0.26 cm yr−1, −0.33%). The traits waxiness, leaf rolling, harvest index, spike length, and grains per spike significantly increased but the gain was only 0.16–0.2% per year. Analysis of variance revealed that genotype, environment, and G×E interaction were highly significant (P< .01) for all traits except relative chlorophyll content, biomass, days to maturity, and number of spikes. Gene‐specific markers identified the durable resistance gene Lr67/Yr46/Sr55/Pm46in obsolete cultivars as early as 1911, whereas the photoperiod‐insensitive allele Ppd‐D1aand reduced height alleles Rht‐B1band Rht‐D1bwere present only in the post‐1965 cultivars. Diversity analysis based on a 50K single nucleotide polymorphism genotyping array clearly differentiated temporal patterns in 24 cultivars, which was correlated with the agronomic performance of the cultivars. This dataset provided detailed insight into the performance of historical wheat cultivars and could help in devising wheat breeding strategies to focus on the traits contributing to grain yield and have slower rate of genetic progress. The genetic gain in morphology of Pakistani bread wheat cultivars over 105 yr areas was assessed.Leaf rolling, waxiness, and grains/spikes associated with genetic gains in grain yield were achieved by breeding.The performance and stability of yield and yield‐related traits was analyzed for the different cultivars.

This study evaluated alkylresorcinol concentration (ARC) in recombinant inbred lines (RILs) from the cross of Zhongmai 578 and Jimai 22 in three environments. ARC exhibited a continuous distribution ranging from 337.4 to 758.0, 495.4–768.0, and 456.3–764.7 μg/g, respectively, in three environments. Analysis of variance (ANOVA) indicated significant (P< 0.001) impacts of genotypes, environments, and their interactions. The broad-sense heritability of ARC was 0.76. Genome-wide linkage mapping analysis identified four stable quantitative trait loci (QTL) for ARC on chromosomes 2A, 3A, 4D, and 7A. Kompetitive allele-specific PCR (KASP) marker of each QTL was developed and validated in 206 representative wheat varieties. Wheat varieties harboring 0, 1, 2, 3, and 4 favorable alleles had ARC of 499.1, 587.8, 644.7, 668.5, and 711.1 μg/g, respectively. This study suggests that combining multiple minor-effect QTL through KASP markers can serve as an effective strategy for breeding high-ARC wheat, thereby enhancing innovations in functional food production.

Black point, a black discoloration of the grain embryo, downgrades the grain quality and commodity grade. Identification of the underlying genetic loci can facilitate the improvement of black point resistance in wheat. Here, 262 recombinant inbred lines (RILs) from the cross of Zhongmai 578/Jimai 22 were evaluated for black point reaction in five environments. A high-density genetic linkage map of the RIL population was constructed with the wheat 50K single nucleotide polymorphism (SNP) array. Six stable QTLs for black point resistance, QBp.caas-2A, QBp.caas-2B1, QBp.caas-2B2, QBp.caas-2D, QBp.caas-3Aand QBp.caas-5Bwere detected, explaining 2.1-28.8% of the phenotypic variances. The resistance alleles of QBp.caas-2B1and QBp.caas-2B2were contributed by Zhongmai 578 while the others were from Jimai 22. QBp.caas-2B2, QBp.caas-2Dand QBp.caas-3Aare overlapped with previously reported loci, whereas QBp.caas-2A, QBp.caas-2B1and QBp.caas-5Bare likely to be new. Five KASP markers, Kasp_2A_BP, Kasp_2B1_BP, Kasp_2B2_BP, Kasp_3A_BPand Kasp_5B_BPwere validated in a natural population of 165 cultivars. The findings provide useful QTL and molecular markers for improvement of black point in wheat resistance in marker-assisted breeding.

Wheat cultivar Zhongmai 895 was earlier found to carry YR86in an 11.6 Mb recombination-suppressed region on chromosome 2AL when crossed with Yangmai 16. To fine-map the YR86locus, we developed two large F2populations from crosses Emai 580/Zhongmai 895 and Avocet S/Zhongmai 895. Remarkably, both populations exhibited suppressed recombination in the same 2AL region. Collinearity analysis across Chinese Spring, Aikang 58, and 10 + wheat genomes revealed a 4.1 Mb chromosomal inversion spanning 708.5–712.6 Mb in the Chinese Spring reference genome. Molecular markers were developed in the breakpoint and were used to assess a wheat cultivar panel, revealing that Chinese Spring, Zhongmai 895, and Jimai 22 shared a common sequence named InvCS, whereas Aikang 58, Yangmai 16, Emai 580, and Avocet S shared the sequence named InvAK58. The inverted configuration explained the suppressed recombination observed in all three bi-parental populations. Normal recombination was observed in a Jimai 22/Zhongmai 895 F2population, facilitating mapping of YR86to a genetic interval of 0.15 cM corresponding to 710.27–712.56 Mb falling within the inverted region. Thirty-three high-confidence genes were annotated in the interval using the Chinese Spring reference genome, with six identified as potential candidates for YR86based on genome and transcriptome analyses. These results will accelerate map-based cloning of YR86and its deployment in wheat breeding.

Despite recent advances in crop metabolomics, the genetic control and molecular basis of wheat kernel metabolomes at different developmental stages remain largely unknown. Here, we performed a widely-targeted metabolic profiling in kernels at three developmental stages, namely grain filling kernels (FK), mature kernels (MK) and germinating kernels (GK), using a population of 159 recombinant inbred lines (RILs). A total of 625 annotated metabolites were detected, and 3173, 3143 and 2644 metabolite quantitative trait loci (mQTL) were mapped in FK, MK and GK, respectively. Only 52 mQTL were simultaneously mapped in all three stages, indicating a high stage-specificity of the wheat kernel metabolome. Subsequently, four candidate genes were functionally validated by in vitroenzymatic reactions and/ or transgenic approaches in wheat, with three of these mediating the tricin metabolic pathway. Meanwhile, both metabolite flux efficiencies within the tricin pathway and the superior candidate haplotypes were evaluated. Thus, the current work represents a comprehensive delineation of the pathway of tricin metabolism in wheat. Finally, further wheat metabolic pathways were re-constructed by updating them to incorporate the 177 candidates identified in the current study. To this end, our work not only provides new knowledge on wheat kernel metabolome variations, but also identifies important molecular resources for wheat nutritional quality improvement.

Stripe or yellow rust (YR) and leaf rust (LR) cause large losses in wheat production worldwide. Resistant cultivars curtail the levels of losses. The present study aimed to identify quantitative trait loci (QTL) for YR and LR resistance in 147 F2:6recombinant inbred lines (RIL) derived from the cross Fuyu 3/Zhengzhou 5389. The RIL population and parents were genotyped with the Wheat55K single nucleotide polymorphism (SNP) array and simple sequence repeat (SSR) markers. All materials were also phenotyped for YR severity at Mianyang in Sichuan province and Baoding in Hebei province in the 2015/2016, 2016/2017, and 2017/2018 cropping seasons, and LR severity at Zhoukou in Henan province and at Baoding in 2017/2018. Eleven QTL for YR resistance and five for LR resistance were detected using inclusive composite interval mapping (IciMapping). Four of these QTL on chromosomes 1BL, 2BS, 3AL, and 5AL conferred resistance to both YR and LR. The QTL on 1BL was Lr46/Yr29, and that on 7BL might be Lr68. The QTL on chromosome 2BS was detected at a similar position to previously detected loci. QYr.hebau-3AL/QLr.hebau-3AL, QYr.hebau-5AL/QLr.hebau-5AL, QYr.hebau-7DL, QYr.hebau-4BS, QYr.hebau-6DL, and QYr.hebau-2ASare likely to be new. An SSR marker for QYr.hebau-7DLwas developed and validated in a diverse wheat panel from China, suggesting effectiveness in different genetic backgrounds. These QTL with closely linked SNP and SSR markers could be useful for marker-assisted selection in wheat breeding programs targeting durable resistance to both diseases.

The primary cause of time‐dependent discoloration in wheat (Triticum aestivumL.)‐based products is polyphenol oxidase (PPO) activity. A comprehensive genetic characterization of PPO activity in wheat could expedite the development of wheat varieties with low PPO activity. To dissect the genetic architecture of PPO activity in wheat flour, a panel of 166 diverse bread wheat cultivars was phenotyped in four different environments and genotyped by high‐density wheat 90K and 660K arrays. A genome‐wide association study (GWAS) was performed by a mixed linear model that incorporated population structure and relative kinship. Four hundred and sixty‐five stable marker–trait associations representative of 43 quantitative trait loci (QTL) for PPO activity identified in at least two environments were located on all wheat chromosomes except 5A, with each explaining 6.6–32.4% of the phenotypic variance. Based on IWGSC RefSeq v1.0, we found that QPPO2A.3, QPPO2B.1, QPPO2B.2, and QPPO2D.2were consistent with the previously reported QTL, and 12 QTL located on homoeologous group 1 chromosomes (6 QTL), chromosomes 4B, 4D, and 7A (2 QTL), and chromosome 7B (2 QTL) are likely to be new PPO loci. Based on physical positions of QTL and previous studies, Ppo‐A1, Ppo‐A2, Ppo‐B2, Ppo‐D2, Pinb‐D1, and genes encoding a Cu ion‐binding protein and a Cu‐transporting ATPase RAN1‐like protein were considered as candidates for QPPO2A.3, QPPO2B.1, QPPO2D.2, QPPO5D.1, QPPO4A.2, and QPPO7D.2, respectively. This study provided insights into the molecular basis of wheat PPO activity, and associated markers can be used for selection of low PPO breeding lines as a means of improving the marketing quality of wheat products.

The objective of this paper is to review progress made in wheat breeding for Fusarium head blight (FHB) resistance in China, the United States of America (USA), and Canada. In China, numerous Chinese landraces possessing high levels of FHB resistance were grown before the 1950s. Later, pyramiding multiple sources of FHB resistance from introduced germplasm such as Mentana and Funo and locally adapted cultivars played a key role in combining satisfactory FHB resistance and high yield potential in commercial cultivars. Sumai 3, a Chinese spring wheat cultivar, became a major source of FHB resistance in the USA and Canada, and contributed to the release of more than 20 modern cultivars used for wheat production, including the leading hard spring wheat cultivars Alsen, Glenn, Barlow and SY Ingmar from North Dakota, Faller and Prosper from Minnesota, and AAC Brandon from Canada. Brazilian wheat cultivar Frontana, T. dicoccoidesand other local germplasm provided additional sources of resistance. The FHB resistant cultivars mostly relied on stepwise accumulation of favorable alleles of both genes for FHB resistance and high yield, with marker-assisted selection being a valuable complement to phenotypic selection. With the Chinese Spring reference genome decoded and resistance gene Fhb1now cloned, new genomic tools such as genomic selection and gene editing will be available to breeders, thus opening new possibilities for development of FHB resistant cultivars.

Background: Plant architecture associated with increased grain yield and adaptation to the local environments is selected during wheat (Triticum aestivum) breeding. The internode length of individual stems and tiller length of individual plants are important for the determination of plant architecture. However, few studies have explored the genetic basis of these traits. Results: Here, we conduct a genome-wide association study (GWAS) to dissect the genetic basis of geographical differentiation of these traits in 306 worldwide wheat accessions including both landraces and traditional varieties. We determine the changes of haplotypes for the associated genomic regions in frequency in 831 wheat accessions that are either introduced from other countries or developed in China from last two decades. We identify 83 loci that are associated with one trait, while the remaining 247 loci are pleiotropic. We also find 163 associated loci are under strong selective sweep. GWAS results demonstrate independent regulation of internode length of individual stems and consistent regulation of tiller length of individual plants. This makes it possible to obtain ideal haplotype combinations of the length of four internodes. We also find that the geographical distribution of the haplotypes explains the observed differences in internode length among the worldwide wheat accessions. Conclusion: This study provides insights into the genetic basis of plant architecture. It will facilitate gene functional analysis and molecular design of plant architecture for breeding.

Background: Large-scale genotype–phenotype association studies of crop germplasm are important for identifying alleles associated with favorable traits. The limited number of single-nucleotide polymorphisms (SNPs) in most wheat genome-wide association studies (GWASs) restricts their power to detect marker-trait associations. Additionally, only a few genes regulating grain number per spikelet have been reported due to sensitivity of this trait to variable environments. Results: We perform a large-scale GWAS using approximately 40 million filtered SNPs for 27 spike morphology traits. We detect 132,086 significant marker-trait associations and the associated SNP markers are located within 590 associated peaks. We detect additional and stronger peaks by dividing spike morphology into sub-traits relative to GWAS results of spike morphology traits. We propose that the genetic dissection of spike morphology is a powerful strategy to detect signals for grain yield traits in wheat. The GWAS results reveal that TaSPL17positively controls grain size and number by regulating spikelet and floret meristem development, which in turn leads to enhanced grain yield per plant. The haplotypes at TaSPL17indicate geographical differentiation, domestication effects, and breeding selection. Conclusion: Our study provides valuable resources for genetic improvement of spike morphology and a fast-forward genetic solution for candidate gene detection and cloning in wheat.

Wheat high-molecular-weight glutenin subunits (HMW-GS) determine dough elasticity and play an essential role in processing quality. HMW-GS are encoded by Glu-1genes and controlled primarily at transcriptional level, implemented through the interactions between cis-acting elements and trans-acting factors. However, transcriptional mechanism of Glu-1genes remains elusive. Here we made a comprehensive analysis of cis-regulatory elements within 1-kb upstream of the Glu-1start codon (−1000 to −1) and identified 30 conserved motifs. Based on motif distribution pattern, three conserved cis-regulatory modules (CCRMs), CCRM1 (−300 to −101), CCRM2 (−650 to −400), and CCRM3 (−950 to −750), were defined, and their functions were characterized in wheat stable transgenic lines transformed with progressive 5′ deletion promoter::GUS fusion constructs. GUS staining, qPCR and enzyme activity assays indicated that CCRM2 and CCRM3 could enhance the expression level of Glu-1, whereas the 300-bp promoter (−300 to −1), spanning CCRM1 and core region (−100 to −1), was enough to ensure accurate Glu-1initiation at 7 days after flowering (DAF) and shape its spatiotemporal expression pattern during seed development. Further transgenic assays demonstrated that CCRM1-2 (−300 to −209) containing Complete HMW Enhancer (−246 to −209) was important for expression level but had no effect on expression specificity in the endosperm. In contrast, CCRM1-1 (−208 to −101) was critical for both expression specificity and level of Glu-1. Our findings not only provide new insights to uncover Glu-1transcription regulatory machinery but also lay foundations for modifying Glu-1expression.

ObjectiveDescription of the design and preliminary results of baseline recruitment and screening in the endoscopic screening for esophageal cancer in China (ESECC), the first randomised controlled trial (RCT) assessing efficacy and cost-effectiveness of endoscopic screening for esophageal squamous cell carcinoma (ESCC).DesignESECC trial is a cluster RCT, and 668 villages in rural Hua County, Henan Province, a high-incidence area of ESCC in China, were randomised into two arms at a ratio of 1:1. Screening arm participants were screened by Lugol chromoendoscopy; no screening was performed in the control arm. ESCC-specific and all-cause mortality, incidence of advanced ESCC and cost-effectiveness of screening will be evaluated in the next 10-year follow-up. Here, we report the performance of baseline recruitment and randomisation, prevalence of upper GI lesions and risk factors for ESCC.ResultsA total of 17 151 and 16 797 participants were enrolled in screening and control arms from January 2012 to September 2016. The truncated prevalence (aged 45–69 years) of oesophageal and overall upper GI high-grade lesions was 744.0/100 000 and 902.0/100 000. 69.9% of the 113 patients with high-grade oesophageal lesions were of early stage. Risk factors for severe oesophageal dysplasia and more severe lesions in this population included higher age, family history of ESCC, lower body mass index, eating rapidly and frequent ingestion of leftovers.ConclusionThis ESECC trial met the predesigned recruitment and randomisation requirements. Age, family history, undernutrition and unhealthy dietary habits increased the risk for high-grade oesophageal lesions in this high-risk population.Trail registration numberNCT01688908; Pre-results.

Rht24is a major dwarfing allele that not only reduces plant height but also increases grain weight. The objective of this study was to trace the source, spread, and distribution of Rht24and determine its frequency in conjunction with other important dwarfing alleles for Rht1(Rht‐B1b), Rht2(Rht‐D1b), and Rht8. Allele‐specific cleaved amplified polymorphic sequence (CAPS) markers were developed for accurate and effective genotyping of Rht1and Rht2, and closely linked flanking markers were used for genotyping of Rht8and Rht24. Marker analysis showed that Rht24occurs at a higher frequency (84.2%) than other important dwarfing alleles in elite wheat (Triticum aestivumL.) varieties and usually couples with Rht2or Rht8. Genotyping of old varieties and landraces showed that Rht24was widely used in wheat breeding before the Green Revolution (GR). ‘Akakomugi’ and ‘Norin 10’, the donors of Rht8and GR genes Rht1and Rht2, respectively, harbored Rht24, so Rht24likely followed the transfer routes of GR genes and Rht8to spread worldwide. Pedigree analysis showed that many Chinese elite lines and backbone parents were derived from Akakomugi, contributing to the high frequency of Rht24in Chinese varieties. Additionally, Norin 10‐derived semidwarf varieties from the CIMMYT were widely used in Chinese wheat breeding. Finally, Rht24was also detected in 30 old Chinese varieties and landraces. Overall, these findings show that the presence of Rht24in modern Chinese elite varieties originated from Akakomugi, Norin 10, or Chinese landraces. Thus, Rht24was introgressed early, spread widely, and became genetically fixed in a wide range of modern Chinese wheat germplasm.

Consumption of Chinese steamed bread (CSB) and noodles made from whole grain wheat flour (WWF) is encouraged due to their important nutritional elements in the outer seed layers that benefit human health. However, the use of WWF is limited because of the poor processing quality and less attractive product properties of dark color, rough texture and coarse crumb structure. Three Chinese wheat cultivars, Zhongmai 895, Yumai 49, and Zhoumai 27, were used to investigate the potentials of bran hydration and autoclaving treatments for the improvement of WWF functionality in making CSB and noodles. Bran particle size, hydration, and autoclaving treatment of WWF significantly affected the quality of dough, CSB, and noodles made from it. Farinograph water absorption and stability of WWFs with fine bran were larger than those with coarse bran. WWFs with coarse bran compared with fine bran exhibited inferior color and higher water retention capacity (WRC), and produced CSB with better texture and crumb structure and noodles with less smoothness and poor appearance. Prehydration of bran decreased dough water absorption and increased dough stability. WWFs containing bran hydrated to 40% moisture content produced CSB with the best texture and crumb structure, and the highest total score. Bran hydration merely induced negative effects on smoothness of noodles made with fine bran. Autoclaving of bran significantly improved texture and crumb structure of CSB made from WWFs with bran hydrated to 40% moisture. Autoclaved bran with 20% moisture contributed to higher total score of CSB. However, bran hydration and autoclaving resulted in darker color of noodle sheet made from WWFs. Hydration and autoclaving of bran could be an effective way to improve the processing quality of CSB made from WWFs, but there was little improvement in eating quality of noodles made from WWFs. This is the first research to show that hydration and autoclaving of bran could be an effective way to improve the processing quality of CSB made from WWFs. These results provide useful information for the incorporation of wheat bran to make fiber‐rich CSB.

The genomic characteristics during the carcinogenic process of esophageal squamous cell carcinoma (ESCC) remain largely unknown. We report here the genomic characteristics of 106 esophageal tissues of various stages from a population-based screening cohort in China (“Endoscopic Screening for Esophageal Cancer in China” trial) and 57 ESCC tissues from a local hospital. A significant increase in somatic mutation and copy number alterations is observed in the non-dysplastic Lugol unstaining lesions (ND-LULs). Extensive clonal expansion has emerged in the ND-LULs to an extent similar to that in higher-stage lesions. The burden of genomic alterations correlates with the size of LULs in the ND-LULs. 8-year follow-up shows that ND-LULs harbor an increased risk of progression to ESCC (adjusted IRR6–10 mm vs. none = 4.66, adjusted IRR>10 mm vs. none = 40.70), and the risk is correlated with LUL size for both non-dysplastic and dysplastic lesions. Lugol unstaining can be the initial stage in the carcinogenic process of ESCC.

Vitamin B is essential for maintaining normal life activities in humans and animals who have to intake the microelement from the outside, especially from cereal products. In the present study 166 Chinese and foreign wheat cultivars planted in two environments were characterized for variation in vitamin B1 and B2 contents. A genome-wide association study (GWAS) using the wheat 90K SNP assay identified 17 loci for vitamin B1 and 7 for vitamin B2 contents. Linear regression analysis showed a significantly positive correlation of the number of favorable alleles with vitamin B1 and B2 contents. Marker-trait associations (MTAs) at IWB43809(6AS, 0cM) and IWB69903(6AS, 13cM) were new and stable, and significantly associated with vitamin B1 content across two environments. The loci identified in this study and associated SNP markers could be used for improvement of vitamin B1 and B2 contents to obtain superior quality along with grain yield in wheat.

Heat stress during the grain-filling stage is a major limiting factor for improving Chinese wheat production, and its effect on functional properties of flours and starches in 10 leading cultivars from the Yellow and Huai Valleys grown under normal and heat-stress environments was investigated. Heat stress during the grain-filling stage decreased total starch content but increased protein and lipid contents of wheat grains. Amylose content of wheat starch was little altered under a heat-stress environment. Heat stress did not significantly change swelling power and starch solubility of wheat starches but significantly decreased swelling power of wheat flours. Pasting viscosities of wheat starches and flours were affected differentially by heat stress. Heat stress had a significant effect on gelatinization and retrogradation properties of starches. The in vitro enzymatic digestibility of wheat starches was affected slightly by heat stress. Analysis of variance indicated that heat stress had a significant effect on some functional properties of starch and flour, although the largest source of variability in these properties was cultivar.

Understanding the key characteristics associated with genetic gains achieved through breeding is essential for improving yield‐limiting factors and designing future breeding strategies in bread wheat (Triticum aestivumL.) cultivars. The objective of the present study was to investigate the genetic progress in yield‐related and physiological traits in cultivars released from 1950 to 2012 for irrigated conditions in the southern Yellow and Huai Valleys Winter Wheat Zone. Field trials including 26 leading cultivars from 1950 to the present time were conducted at Zhengzhou and Zhoukou in Henan Province, during the 2013–2014 and 2014–2015 cropping seasons, providing data from four environments. Grain yield (GY) was significantly increased by the linear rate of 57.5 kg ha−1yr−1or 0.70% (R2= 0.66, P< 0.01) and significantly correlated with increased thousand‐kernel weight (TKW) (r= 0.48, P< 0.05), spike number m−2(r= 0.44, P< 0.05), kernels m−2(r= 0.56, P< 0.01), aboveground biomass (AGBM) (r= 0.80, P< 0.01), harvest index (HI) (r= 0.84, P< 0.01), water‐soluble carbohydrate at 10 d postanthesis (WSC‐10) (r= 0.80, P< 0.01), and reduced plant height (PH) (r= −0.85, P< 0.01). There was no significant change in kernel number per spike, heading date, normalized difference in vegetation index at anthesis and at 10 d postanthesis, leaf area index at anthesis and at 10 d postanthesis, and canopy temperature depression at anthesis during the past 60 yr. Soil plant analysis development (SPAD) estimates of chlorophyll content at 10 d postanthesis (Chl‐10) increased with year of release and were significantly correlated with GY (r= 0.69, P< 0.01), PH (r= −0.76, P< 0.01), AGBM (r= 0.52, P< 0.01), HI (r= 0.71, P< 0.01), and WSC‐10 (r= 0.73, P< 0.01). Cultivars conferring Rht‐D1band Rht‐D1b+ Rht8cshowed increased GY, TKW, AGBM, HI, WSC‐10, and Chl‐10. Stem water solubility content can be used as a selection criterion for further improving yield potential.

Many genetic loci for wheat plant height (PH) have been reported, and 26 dwarfing genes have been catalogued. To identify major and stable genetic loci for PH, here we thoroughly summarized these functionally or genetic verified dwarfing loci from QTL linkage analysis and genome-wide association study published from 2003 to 2022. A total of 332 QTL, 270 GWAS loci and 83 genes for PH were integrated onto chromosomes according to their locations in the IWGSC RefSeq v2.1 and 65 QTL-rich clusters (QRC) were defined. Candidate genes in each QRC were predicted based on IWGSC Annotation v2.1 and the information on functional validation of homologous genes in other species. A total of 38 candidate genes were predicted for 65 QRC including three GA2oxgenes in QRC-4B-IV, QRC-5A-VIII and QRC-6A-II (Rht24) as well as GA 20-oxidase 2(TaSD1-3A) in QRC-3A-IV. These outcomes lay concrete foundations for map-based cloning of wheat dwarfing genes and application in breeding.

Skin infections with cutaneous human papillomavirus (HPV) have been linked to the development of non-melanoma skin cancer, in which mucosal HPV may also play a crucial role. However, systematic investigations of the distribution and associated factors of HPV infection in healthy skin of the general population are scarce. HPV DNA from palmar exfoliated cells of 2,087 individuals was detected by FAP6085/64 and SPF1/GP6+ primers followed by sequencing. A total of 338 papillomavirus types were detected, with HPV-3, HPV-57, and HPV-49 being the most dominant types. The overall prevalence for HPV DNA on skin was 79.92% and for alpha-, beta-, and gamma-HPV were 27.07%, 38.76%, and 29.56%, respectively. Having multiple lifetime sexual partners (adjusted odds ratio 1.60), being a migrant worker (adjusted odds ratio 2.05, reference: farmers), and frequent bathing (Ptrend = 0.001) were associated with alpha-HPV DNA presence. Advancing age increased the detection risk of beta-HPV (Ptrend = 0.001). Higher education (Ptrend = 0.017) and frequent bathing (Ptrend = 0.001) were positively related to gamma-HPV positivity. This study demonstrates that alpha-HPV commonly exists on healthy skin of the general population in rural China, and alpha- and gamma-HPV infections are related to certain behaviors, different from beta-HPV infection. These findings are crucial to better understanding the biology of HPV infection and may be suggestive of the potential transmission of these viruses.

We investigated alleles at 31 loci associated with adaptability, yield, and end‐use quality in 107 wheat (Triticum aestivumL.) landraces (WLRs) and 121 improved historical wheat cultivars (HWCs) from Pakistan. The WLRs were categorized into two further subgroups: 36 pre‐Green‐Revolution landraces released as cultivars and 71 geographically spread landraces from all over Pakistan. Alleles Vrn‐A1a, TaGW2‐6A‐A, TaCKX6‐D1b, Pinb‐D1b, Psy‐A1b, and Wx‐D1bwere absent in WLRs, whereas ample diversity was observed at all other loci. In HWCs, only Wx‐D1band Glu‐A3ewere absent among the alleles tested, whereas the alleles Ppd‐D1a(90%), Rht‐B1bor Rht‐D1b(83.4%), TaCwi‐A1a(95%), TaGW2‐6A‐G(76%), TaCKX6‐D1a(77.3%), Glu‐A1b(66.1%), Glu‐D1d(61.3%), Pina‐D1b(88.2%), Pinb‐D1a(90%), Psy‐A1a(66.1%), Psy‐B1b(81.8%), Psy‐D1a(86.5%), Ppo‐A1a(70%), TaZds‐D1b(73.9%), TaLox‐B1b(80.1%), and Wx‐D1a(100%) predominated, indicating significant improvement in adaptability, yield potential, and end‐use quality and unconscious selection for favored alleles. Higher frequencies of favored alleles at the TaCwi‐A1and TaCKX6‐D1loci influencing 1000‐kernel weight (TKW) in HWCs indicated that selection pressure on these alleles during breeding successfully contributed to cultivar improvement. Wright's pairwise fixation index (Fst) statistics indicated greater genetic divergence between HWC and WLR collections (0.16) than HWC and WLR cultivars (0.14). Population structure based on functional markers (FMs) using principal component analysis partitioned the germplasm into two distinct groups. High genetic divergence and low admixture between HWCs and WLRs indicated limited use of landraces in wheat breeding in Pakistan. Our results suggested these collections as rich reservoirs of alleles and haplotype combinations that may be useful in future breeding programs.

The recently published reference genome of Aegilops tauschiiprovides new insights into the originator of the D genome donor of hexaploid wheat. This will be a foundation for exploring the genomic diversity underpinning adaptive traits in wheat, and ultimately advance wheat improvement efforts.

By adding high-resolution climatic factors to an innovative genotype-by-environment model, a study using high-quality data of global wheat trials demonstrates that climate change affects wheat breeding and that region-specific breeding efforts that target heat-tolerance traits achieve better yield stability in a warming climate.

ABSTRACTThe association between human papillomavirus 31 (HPV31) DNA loads and the risk of cervical intraepithelial neoplasia grades 2 and 3 (CIN2–3) was evaluated among women enrolled in the atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesion (LSIL) triage study (ALTS), who were monitored semiannually over 2 years and who had HPV31 infections detected at =1 visit. HPV31 DNA loads in the first HPV31-positive samples and in a random set of the last positive samples from women with =2 HPV31-positive visits were measured by a real-time PCR assay. CIN2–3 was histologically confirmed at the same time as the first detection of HPV31 for 88 (16.6%) of 530 women. After adjustment for HPV31 lineages, coinfection with other oncogenic types, and the timing of the first positive detection, the odds ratio (OR) per 1-log-unit increase in viral loads for the risk of a concurrent diagnosis of CIN2–3 was 1.5 (95% confidence interval [CI], 1.2 to 1.9). Of 373 women without CIN2–3 at the first positive visit who had =1 later visit, 44 had subsequent diagnoses of CIN2–3. The initial viral loads were associated with CIN2–3 diagnosed within 6 months after the first positive visit (adjusted OR, 1.5 [95% CI, 1.0 to 2.4]) but were unrelated to CIN2–3 diagnosed later. For a random set of 49 women who were tested for viral loads at the first and last positive visits, changes in viral loads were upward and downward among women with and without follow-up CIN2–3 diagnoses, respectively, although the difference was not statistically significant. Results suggest that HPV31 DNA load levels at the first positive visit signal a short-term but not long-term risk of CIN2–3.

Plant height (PH) and yield components are important traits for yield improvement in wheat breeding. In this study, 207F2:4 recombinant inbred lines (RILs) derived from the cross Jingdong 8/Aikang 58 were investigated under limited and full irrigation environments at Beijing and Gaoyi, Hebei province, during the 2011–12 and 2012–13 cropping seasons. The RILs were genotyped with 149 polymorphic simple sequence repeat (SSR) markers, and quantitative trait loci (QTLs) for PH and yield components were analysed by inclusive composite interval mapping. All traits in the experiment showed significant genetic variation and interaction with environments. The range of broad-sense heritabilities of PH, 1000-kernel weight (TKW), number of kernels per spike (KNS), number of spikes per m2 (NS), and grain yield (GY) were 0.97–0.97, 0.87–0.89, 0.59–0.61, 0.58–0.68, and 0.23–0.48. The numbers of QTLs detected for PH, TKW, KNS, NS, and GY were 3, 10, 8, 7 and 9, respectively, across all eight environments. PH QTLs on chromosomes 4D and 6A, explaining 61.3–80.2% of the phenotypic variation, were stably expressed in all environments. QPH.caas-4D is assumed to be the Rht-D1b locus, whereas QPH.caas-6A is likely to be a newly discovered gene. The allele from Aikang 58 at QPH.caas-4D reduced PH by 11.5–18.2% and TKW by 2.6–3.8%; however, KNS increased (1.2–3.7%) as did NS (2.8–4.1%). The QPH.caas-6A allele from Aikang 58 reduced PH by 8.0–11.5% and TKW by 6.9–8.5%, whereas KNS increased by 1.2–3.6% and NS by 0.9–4.5%. Genotypes carrying both QPH.caas-4D and QPH.caas-6A alleles from Aikang 58 showed reduced PH by 28.6–30.6%, simultaneously reducing TKW (13.8–15.2%) and increasing KNS (3.4–4.9%) and NS (6.5–10%). QTKW.caas-4B and QTKW.caas-5B.1 were stably detected and significantly associated with either KNS or NS. Major KNS QTLs QKNS.caas-4B and QKNS.caas-5B.1 and the GY QTL QGY.caas-3B.2 were detected only in water-limited environments. The major TKW QTKW.caas-6D had no significant effect on either KNS or NS and it could have potential for improving yield.

Starch is a crucial component determining the processing quality of wheat-based products such as Chinese steamed bread (CSB) and raw white noodles (RWN). Flour from wheat cultivar Zhongmai 175 was used for fractionation into starch, gluten, and water solubles by hand washing. The starch fraction was successfully separated into large (>10 µm diameter) and small starch granules (<10 µm diameter) by repeated sedimentation. Flour fractions were reconstituted to original levels in the flour by using constant gluten and water solubles and varying the weight ratio of large and small starch granules. As the proportion of small granules increased in the reconstituted flours, farinograph water absorption increased, and amylose content, pasting peak viscosity, trough, and final viscosity decreased. Starch granule size distribution significantly affected processing quality of CSB and RWN. Superior crumb structure score (12.0) was observed in CSB made from reconstituted flour with 35% small starch granules. CSB made from reconstituted flours with 30 and 35% small starch granules exhibited the highest total scores, with values of 85.4 and 83.3, respectively. Significant improvements in color, viscoelasticity, and smoothness of RWN were obtained with an increase in small starch granule content, and reconstituted flours with 30–40% small starch granules produced RWN with moderate firmness.

Powdery mildew caused by Blumeria graminisf. sp. triticiis one of the major wheat diseases worldwide. The Chinese wheat landrace Pingyuan 50 has shown adult-plant resistance (APR) to powdery mildew in the field for over 60years. To dissect the genetic basis of APR to powdery mildew in this cultivar, a mapping population of 137 double haploid (DH) lines derived from Pingyuan 50/Mingxian 169 was evaluated in replicated field trials for two years in Beijing (2009–2010 and 2010–2011) and one year in Anyang (2009–2010). A total of 540 polymorphic SSR markers were genotyped on the entire population for construction of a linkage map and QTL analysis. Three QTL were mapped on chromosomes 2BS (QPm.caas-2BS.2), 3BS (QPm.caas-3BS), and 5AL (QPm.caas-5AL) with the resistance alleles contributed by Pingyuan 50 explaining 5.3%, 10.2%, and 9.1% of the phenotypic variances, respectively, and one QTL on chromosome 3BL (QPm.caas-3BL) derived from Mingxian 169 accounting for 18.1% of the phenotypic variance. QPm.caas-3BS, QPm.caas-3BL, and QPm.caas-5ALappear to be new powdery mildew APR loci. QPm.caas-2BS.2and QPm.caas-5ALare possibly pleiotropic or closely linked resistance loci to stripe rust resistance QTL. Pingyuan 50 could be a potential genetic resource to facilitate breeding for improved APR to both powdery mildew and stripe rust.

Leaf rust and powdery mildew, caused by Puccinia triticinaand Blumeria graminisf. sp. tritici, respectively, are widespread fungal diseases of wheat (Triticum aestivumL.). Development of cultivars with durable resistance is crucially important for global wheat production. This paper reviews the progress of genetic study and application of adult plant resistance (APR) to wheat leaf rust and powdery mildew. Eighty leaf rust and 119 powdery mildew APR quantitative trait loci (QTL) have been reported on 16 and 21 chromosomes, respectively, in over 50 publications during the last 15 yr. More important, we found 11 loci located on chromosomes 1BS, 1BL, 2AL, 2BS (2), 2DL, 4DL, 5BL, 6AL, 7BL, and 7DS showing pleiotropic effects on resistance to leaf rust, stripe rust, and powdery mildew. Among these, QTL on chromosomes 1BL, 4DL, and 7DS also correlate with leaf tip necrosis. Fine mapping and cloning of these QTL will be achieved with the advent of cheaper high‐throughput genotyping technologies. Germplasm carrying these potential resistance genes will be useful for developing cultivars with durable multidisease resistance. In addition to its non‐NBS–LRR (nucleotide binding site–leucine rich repeat) structure, the senescence‐like processes induced by Lr34could be the reason for durability of resistance; however, more information is needed for a full understanding of the molecular mechanism related to durability. Adult plant resistance genes have been used by CIMMYT for more than 30 yr and have also been transferred to many Chinese wheat varieties through shuttle breeding.

The puroindoline genes (Puroindoline a‐D1and Puroindoline b‐D1), located very near to the distal end of the short arm of chromosome 5D (distal to fraction arm length of 0.78) have a significant effect on grain hardness. Puroindoline b‐2(Pinb‐2) is another puroindoline gene family that exists as a homoeologous series on group 7 chromosomes. However, a more detailed localization (physical mapping) of the Pinb‐2genes has not been conducted. In the present study, 24 group 7 long‐arm chromosome deletion stocks of ‘Chinese Spring’ were used to physically map three Pinb‐2variant genes: Pinb‐2v1, Pinb‐2v2, and Pinb‐2v4. All three genes were found to be physically located on the most distal 0.11 to 0.16 fraction arm length of chromosomes 7AL, 7BL, and 7DL in Chinese Spring. These results contribute insight into wheat (Triticum aestivumL.) genome synteny, structure, and organization and provide a useful metric for germplasm and population relationships. Future studies may further resolve the physical mapping of Pinb‐2genes at the ends of group 7 chromosomes and contribute to a better understanding of the molecular and genetic basis of kernel hardness.

Lipoxygenase (LOX) activity in grain influences the color and processing quality of wheat (Triticumspp.)‐based products. Characterization of LOX genes and development of functional markers are of importance for marker‐assisted selection in common wheat (Triticum aestivumL.) breeding. In the present study, the full‐length genomic DNA (gDNA) sequence of a LOX gene (designated TaLox‐B1) located on chromosome 4BS was characterized by in silico cloning and experimental validation. Two complementary dominant sequence tagged site (STS) markers, LOX16 and LOX18, were developed based on the single nucleotide polymorphism (SNP) of two alleles at the TaLox‐B1locus, amplifying 489‐ and 791‐bp fragments in cultivars with higher and lower LOX activities, respectively. The two markers were mapped on chromosome 4BS using a doubled haploid (DH) population derived from Zhongyou 9507 × CA9632, a set of Chinese Spring nullisomic–tetrasomic lines, ditelosomic line 4BS, and Langdon (LDN) 4D(4B) chromosome substitution line. Quantitative trait loci (QTL) analysis indicated that TaLox‐B1co‐segregated with the two functional markers and was closely linked to simple sequence repeat (SSR) locus Xgwm251on chromosome 4BS with a genetic distance of 1.8 cM. LOX16 and LOX18 were validated on 198 Chinese wheat cultivars and advanced lines and showed highly significant (p< 0.01) associations with LOX activity. These results suggested that LOX16 and LOX18, co‐segregating with TaLox‐B1, could be used for the improvement of color attributes of noodles and other wheat‐based products in wheat breeding programs.

The improvement of kernel morphology traits is an important goal in common wheat (Triticum aestivum L.) breeding programs because of their close relationship with grain yield and milling quality. The aim of this study was to map quantitative trait loci (QTL) for kernel morphology traits using 240 recombinant inbred lines derived from a cross between the non-1BL.1RS translocation cv. PH 82-2 and the 1BL.1RS translocation cv. Neixiang 188, grown in six environments in China. Inclusive composite interval mapping identified 71 main-effect QTL on 16 chromosomes for seven kernel morphology traits measured by digital imaging, viz. kernel length, width, perimeter, area, shape factor, factor form-density and width/length ratio. Each of these loci explained from 2.6 to 28.2% of the phenotypic variation. Eight QTL clusters conferring the largest effects on kernel weight and kernel morphology traits were detected on chromosomes 1BL.1RS (2), 2A, 4A, 4B, 6B, 6D and 7A. Fourteen epistatic QTL were identified for all kernel morphology traits except kernel width/length ratio, involving 24 main-effect QTL distributed on 13 chromosomes, and explaining 2.5–8.3% of the phenotypic variance. Five loci, viz. Sec-1 on 1BL.1RS, Glu-B1 on 1BL, Xcfe53 on 2A, Xwmc238 on 4B, and Xbarc174 on 7A, were detected consistently across environments, and their linked DNA markers may be used for marker-assisted selection in breeding for improved wheat kernel traits and grain yield.

Zeta (ζ)‐carotene desaturase (ZDS) is a key enzyme in the carotenoid biosynthetic pathway, which determines the yellow pigment (YP) content in wheat (Triticum aestivumL.) grains. In the present study, the full‐length DNA sequence of a ZDS gene on wheat chromosome 2DL, designated TaZds‐D1, was characterized. The TaZds‐D1gene has an open reading frame of 1707 bp, including 13 introns and 14 exons, and a deduced peptide containing 568 amino acid residues with a predicted molecular weight of 62.5 kDa. The TaZds‐D1gene was located on chromosome 2DL based on polymerase chain reaction amplifications of Chinese Spring nullisomic‐tetrasomic lines, Langdon–Chinese Spring D‐genome chromosome disomic substitution lines, and Rusty D‐genome chromosome disomic substitution lines as well as linkage analysis. Two allelic variants, TaZds‐D1aand TaZds‐D1b, were detected in Chinese wheat cultivars, and a functional marker, YP2D‐1, was developed based on the sequence polymorphism between TaZds‐D1aand TaZds‐D1b. A major quantitative trait locus, located at the TaZds‐D1region in the marker interval of YP2D‐1 and Xgwm157on chromosome 2DL, explained 18.4% of the phenotypic variance for YP content in a doubled haploid population derived from the cross Zhongyou 9507/CA 9632. This confirmed the association between allelic variation at the TaZds‐D1locus and YP content.

Low-molecular-weight glutenin subunits (LMW-GS) have significant effects on the processing quality of end-use products of common wheat. It is more efficient to discriminate LMW-GS alleles with PCR-based molecular markers than with SDS-PAGE. In the present study, we developed an allele-specific PCR marker, designated Glu-B3abefg, which can be used to discriminate protein alleles Glu-B3a, b, e, f, and gsimultaneously. Based on ten previously developed allele-specific STS markers, three multiplex PCRs, viz. Glu-B3c+Glu-B3d, Glu-B3b+Glu-B3g, and Glu-B3h+Glu-B3i, were established. Six Glu-B3alleles (b, c, d, g, h, and i) could be discriminated using the three multiplex PCRs. Results of tests on 158 wheat varieties and lines using Glu-B3abefg and the three multiplex PCRs were consistent with those using the ten STS markers separately. The new allele-specific marker and three multiplex PCRs represent an efficient way to undertake marker-assisted selection of Glu-B3alleles.

Phytoene synthase (PSY) genes are involved in the biosynthesis of carotenoid pigments in durum wheat [Triticum turgidumL. subsp durum(Desf.) Husn.], significantly influencing grain yellowness. This study was conducted to identify new allelic variants at the Psy‐A1and Psy‐B1loci in durum wheat, and to evaluate the applicability of functional markers developed from common wheat (Triticum aestivumL.) for durum wheat breeding. Two new allelic variants, Psy‐A1dand Psy‐A1e, were identified at the Psy‐A1locus, and both the codominant markers YP7Aand YP7A‐2can be used to discriminate the two haplotypes, yielding 194‐ and 231‐bp polymerase chain reaction (PCR) products with YP7Aand 1001‐ and 1684‐bp fragments with YP7A‐2, respectively. At the Psy‐B1locus, three allelic variants were identified. Psy‐B1ewas also found in common wheat, whereas Psy‐B1fand Psy‐B1gwere detected only in durum wheat. The codominant marker YP7B‐1can be used to distinguish Psy‐B1fand Psy‐B1g, generating 151‐ and 153‐bp PCR fragments, respectively, and the dominant marker YP7B‐4was specific to haplotype Psy‐B1e, producing a 717‐bp PCR product. In a set of 100 CIMMYT durum wheat lines with widely variable grain yellowness, the frequencies of Psy‐A1d, Psy‐A1e, Psy‐B1e, Psy‐B1f, and Psy‐B1gwere 99, 1, 0, 67, and 33%, respectively, and the genotype Psy‐B1fshowed a significant association with higher grain yellowness, whereas the presence of Psy‐B1gled to lower yellowness. A phylogenetic tree generated from the gene sequences of the allelic variants at Psy‐A1and Psy‐B1loci indicated two parallel lineages of durum–common wheat, suggesting that more than one tetraploid T. turgidumL. subsp. dicoccon(Schrank) Thell. genotypes were involved in the origin of common wheat. Our results suggested that Psy‐B1fshould be paid more attention in durum breeding programs for its association with elevated grain yellowness.

Both cultivar and noodle composition and preparation have important effects on noodle quality. In this study, the effects of flour extraction rate (50, 60, and 70%), added water (33, 35, and 37%), and salt concentration (0, 1, and 2%, w/w) on color and texture of Chinese white noodle (CWN) were investigated using flour samples from five leading Chinese wheat cultivars. The five samples showed large variations in protein content, ash content, flour color, farinograph, and extensigraph parameters, and starch pasting properties. Analyses of variance indicated that cultivar, flour extraction rate, level of water addition, salt concentration, and the interactions had significant effects on color of raw noodle sheets and color and textural properties of CWN. Cultivar and water addition were more important sources of variation than flour extraction rate and salt concentration. The brightness (L*) and redness (a*) values of raw noodle sheets were significantly reduced and increased, respectively, as flour extraction rate increased from 50 to 70%, and noodle scores were slightly higher at flour extraction rates of 50%. Water addition showed different effects on raw noodle sheet color at 2 and 24 hr, and a significant improvement was observed for noodle appearance, firmness, viscoelasticity, smoothness, and total score as water addition increased from 33 to 37%. L* of raw noodle sheets, and firmness and viscoelasticity of cooked noodles, were significantly improved, but noodle flavor significantly deteriorated as salt concentration increased from 0 to 2%; 1% salt produced the highest noodle score. Thus, the recommended composition for laboratory preparation of CWN is 60% flour extraction, 35% water addition, and 1% salt concentration.