Abstract
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.
Highlights
Common wheat (Triticum aestivum L.) is one of the most widely adapted food crops worldwide, providing approximately 30% of global grain production and 20% of the calories consumed by humans (FAO, 2017)
The objectives of this study were to (i) evaluate the phenotypic performance of yield-related traits across different field trials with normal and late sowing mediated heat stress conditions; (ii) identify genomic regions with stable and robust quantitative trait locus (QTL) associated with yield-related traits; (iii) detect QTL controlling heat susceptibility index of thousand grain weight (HSITGW) for two contrasting treatments; and (iv) provide diagnostic markers to be deployed in marker-assisted selection (MAS) breeding for high-yield and heat-tolerant wheat varieties
To construct linkage map for the unlinked regions in the initial map, 81,587 single-nucleotide polymorphism (SNP) from the wheat 90K SNP array were used for genotyping the ND3338/JD6 doubled haploid (DH) population (Wang et al, 2014), and 10,409 (12.76%) SNP markers that showed polymorphism between the parents were used for linkage analysis
Summary
Common wheat (Triticum aestivum L.) is one of the most widely adapted food crops worldwide, providing approximately 30% of global grain production and 20% of the calories consumed by humans (FAO, 2017). Grain yield in wheat is a complex quantitative trait that is strongly influenced by interacting genetic and environmental factors and can usually be broken down into three components: spikes per plant (SPP), grain number per spike (GNS), and thousand grain weight (TGW) (Quarrie et al, 2006; Gao et al, 2015). These yield components are sequentially fixed, influencing each other during the growth cycle, and are affected by other traits, such as plant height (PH), crop phenology, and biomass. A wealth of QTL for grain weight have been identified to date on almost all wheat chromosomes based on linkage mapping
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