Table_1_Global QTL Analysis Identifies Genomic Regions on Chromosomes 4A and 4B Harboring Stable Loci for Yield-Related Traits Across Different Environments in Wheat (Triticum aestivum L.).xlsx

Major advances in wheat production are needed to address global food insecurity under future climate conditions, such as high temperatures. The grain yield of bread wheat (Triticum aestivum L.) is a quantitatively inherited complex trait that is strongly influenced by interacting genetic and environmental factors. Here, we conducted global QTL analysis for five yield-related traits, including spike yield, yield components and plant height (PH), in the Nongda3338/Jingdong6 doubled haploid (DH) population using a high-density SNP and SSR-based genetic map. A total of 12 major genomic regions with stable QTL controlling yield-related traits were detected on chromosomes 1B, 2A, 2B, 2D, 3A, 4A, 4B, 4D, 5A, 6A, and 7A across 12 different field trials with timely sown (normal) and late sown (heat stress) conditions. Co-location of yield components revealed significant tradeoffs between thousand grain weight (TGW) and grain number per spike (GNS) on chromosome 4A. Dissection of a “QTL-hotspot” region for grain weight on chromosome 4B was helpful in marker-assisted selection (MAS) breeding. Moreover, this study identified a novel QTL for heat susceptibility index of thousand grain weight (HSITGW) on chromosome 4BL that explains approximately 10% of phenotypic variation. QPh.cau-4B.2, QPh.cau-4D.1 and QPh.cau-2D.3 were coincident with the dwarfing genes Rht1, Rht2, and Rht8, and haplotype analysis revealed their pleiotropic architecture with yield components. Overall, our findings will be useful for elucidating the genetic architecture of yield-related traits and developing new wheat varieties with high and stable yield.

为应对未来高温等气候条件下的全球粮食安全问题，小麦产量亟需取得重大突破。普通小麦（*Triticum aestivum* L.）的籽粒产量是一类受遗传与环境因子互作强烈影响的数量遗传复杂性状。本研究基于高密度单核苷酸多态性（SNP）与简单序列重复（SSR）遗传图谱，在农大3338/京冬6双单倍体（DH）群体中，对包括穗部产量、产量构成因子及株高（PH）在内的5个产量相关性状开展了全基因组数量性状位点（QTL）分析。在适播（正常）与晚播（热胁迫）环境下的12组不同田间试验中，我们于1B、2A、2B、2D、3A、4A、4B、4D、5A、6A及7A染色体上共检测到12个调控产量相关性状的稳定主效基因组区域。产量构成因子的共定位分析显示，4A染色体上的千粒重（TGW）与每穗粒数（GNS）之间存在显著的权衡关系。对4B染色体上调控粒重的"QTL-hotspot"区域进行解析，有助于标记辅助选择（MAS）育种。此外，本研究在4BL染色体上鉴定到一个全新的千粒重热感指数（HSITGW）QTL，其可解释约10%的表型变异。QPh.cau-4B.2、QPh.cau-4D.1与QPh.cau-2D.3分别与矮秆基因Rht1、Rht2及Rht8重合，单倍型分析揭示了它们与产量构成因子的多效性调控架构。总体而言，本研究结果可为解析产量相关性状的遗传架构及培育高产稳产小麦新品种提供重要理论依据。