Abstract
High yield and wide adaptation are principal targets of wheat breeding but are hindered by limited knowledge on genetic basis of agronomic traits and abiotic stress tolerances. In this study, 277 wheat accessions were phenotyped across 30 environments with non‐stress, drought‐stressed, heat‐stressed, and drought‐heat‐stressed treatments and were subjected to genome‐wide association study using 395 681 single nucleotide polymorphisms. We detected 295 associated loci including consistent loci for agronomic traits across different treatments and eurytopic loci for multiple abiotic stress tolerances. A total of 22 loci overlapped with quantitative trait loci identified by biparental quantitative trait loci mapping. Six loci were simultaneously associated with agronomic traits and abiotic stress tolerance, four of which fell within selective sweep regions. Selection in Chinese wheat has increased the frequency of superior marker alleles controlling yield‐related traits in the four loci during past decades, which conversely diminished favourable genetic variation controlling abiotic stress tolerance in the same loci; two promising candidate paralogous genes colocalized with such loci, thereby providing potential targets for studying the molecular mechanism of stress tolerance–productivity trade‐off. These results uncovering promising alleles controlling agronomic traits and/or multiple abiotic stress tolerances, providing insights into heritable covariation between yield and abiotic stress tolerance, will accelerate future efforts for wheat improvement.
Highlights
Wheat (Triticum aestivum L.) is one of the three major crops providing about 19% of global dietary energy (Ray, Mueller, West, & Foley, 2013)
These results suggest that drought stress represented by rainfed condition in the present study has more negative influence on the seed formation of main spikes compared with terminal heat stress, and the latter may limit the development of young spikes in a greater degree than the former, leading to lower effective spike number per plant (ESNP) and grain yield per plant (GYP)
To gain insights about genetic architecture and candidate genes underlying high yield and wide adaptation of wheat, we investigated the genotypic variability for drought and heat‐responsive agronomic traits under multiple environments and conducted Genome‐wide association study (GWAS) and linkage mapping using high‐density wheat 660K single nucleotide polymorphism (SNP) array
Summary
Wheat (Triticum aestivum L.) is one of the three major crops providing about 19% of global dietary energy (Ray, Mueller, West, & Foley, 2013). Along with the increasing drought stress induced by global warming (Dai, 2013), the identification of QTL/alleles that confer tolerance to drought, heat, and the dual stresses have been regarded as one of the most important task for genetic research in wheat (Lobell, Sibley, & Ivan Ortiz‐Monasterio, 2012; Nevo & Chen, 2010). Both yield potential and abiotic stress tolerance are crucial for wheat improvement, but simultaneously improving these two kinds of traits is a great challenging for crop breeding. Our study aimed to (a) identify stable genetic variations controlling agronomic traits under NS and abiotic (drought and/or heat) stress conditions; (b) identify genetic variations underlying responses for drought, heat and dual stresses; and (c) explore the heritable covariation between yield potential and abiotic stress tolerance, and the variations caused by artificial selection
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