Data_Sheet_2_Breeding Driven Enrichment of Genetic Variation for Key Yield Components and Grain Starch Content Under Drought Stress in Winter Wheat.xlsx

Drought is one of the major abiotic stress factors limiting wheat production worldwide, thus threatening food security. The dissection of the genetic footprint of drought stress response offers strong opportunities toward understanding and improving drought tolerance (DT) in wheat. In this study, we investigated the genotypic variability for drought response among 200 diverse wheat cultivars (genotypes) using agronomic, developmental, and grain quality traits (GQT), and conducted genome-wide association studies (GWAS) to uncover the genetic architectures of these important traits. Results indicated significant effects of genotype, water regime and their interactions for all agronomic traits. Grain yield (GY) was the most drought-responsive trait and was highly correlated with kernels number per meter square (KN). Genome-wide association studies revealed 17 and 20 QTL regions under rainfed and drought conditions, respectively, and identified one LD block on chromosome 3A and two others on 5D associated with breeding progress (BP). The major haplotypes of these LD blocks have been positively selected through breeding and are associated with higher starch accumulation and GY under drought conditions. Upon validation, the identified QTL regions caring favorable alleles for high starch and yield will shed light on mechanisms of tolerance to drought and can be used to develop drought resistant cultivars.

干旱是全球范围内限制小麦生产的重大非生物胁迫因素之一，因而威胁着粮食安全。深入解析干旱胁迫响应的遗传印迹，为理解并提升小麦的抗旱性（DT）提供了巨大的机遇。在本研究中，我们通过农艺性状、发育性状和谷物品质性状（GQT）对200个多样的小麦品种（基因型）的干旱响应进行了基因型变异性的探究，并开展了全基因组关联分析（GWAS）以揭示这些重要性状的遗传结构。研究结果指出，基因型、水分管理及其相互作用对所有农艺性状均具有显著影响。谷物产量（GY）是最敏感的干旱响应性状，与每平方米粒数（KN）高度相关。全基因组关联分析揭示了在雨养和干旱条件下分别存在17个和20个QTL区域，并在3A染色体上鉴定出一个连锁不平衡（LD）块以及5D染色体上的另外两个与育种进展（BP）相关的LD块。这些LD块的主要单倍型已通过育种得到正向选择，并与干旱条件下的高淀粉积累和GY相关。经过验证，所确定的携带有利于高淀粉和产量的有利等位基因的QTL区域，将有助于揭示耐旱机制，并可被用于培育抗旱品种。