Data from: Genome scan identifies flowering-independent effects of barley HsDry2.2 locus on yield traits under water deficit

Increasing crop productivity under climate change requires the identification, selection and utilization of novel alleles for breeding. We analyzed the genotype and field phenotype of the barley HEB-25 multi-parent mapping population under well-watered and water-limited (WW and WL) environments for two years. A genome-wide association study (GWAS) for genotype by-environment interactions was performed for ten traits including flowering time (HEA) and plant grain yield (PGY). Comparison of the GWAS for traits per-se to that for QTL-by-environment interactions (QxE), indicates the prevalence of QxE mostly for reproductive traits. One QxE locus on chromosome 2, Hordeum spontaneum Dry2.2 (HsDry2.2), showed a positive and conditional effect on PGY and grain number (GN). The wild allele significantly reduced HEA, however this earliness was not conditioned by water deficit. Furthermore, BC2F1 lines segregating for the HsDry2.2 showed the wild allele confers an advantage over the cultivated in PGY, GN and harvest index as well as modified shoot morphology , longer grain filling period and reduced senescence (only under drought), therefore suggesting adaptation mechanism against water deficit other than escape. This study highlights the value of evaluating wild relatives in search of novel alleles and clues to resilience mechanism underlying crop adaptation to abiotic stress.气候变化背景下提升作物生产力，亟需鉴定、筛选并利用新型等位基因应用于作物育种。本研究对两年间正常供水（well-watered, WW）与水分限制（water-limited, WL）环境下的大麦HEB-25多亲本作图群体（multi-parent mapping population）开展了基因型与田间表型分析。针对开花时间（HEA）、植株籽粒产量（PGY）等10个性状，进行了基因型×环境互作的全基因组关联分析（genome-wide association study, GWAS）。将针对性状本身的全基因组关联分析结果，与数量性状位点-环境互作（QTL-by-environment interactions, QxE）分析结果进行对比后发现，QxE效应在生殖性状中普遍存在。2号染色体上的1个QxE位点——野生二棱大麦Dry2.2（Hordeum spontaneum Dry2.2, HsDry2.2），对植株籽粒产量与籽粒数（GN）具有正向条件性效应。该野生等位基因可显著缩短开花时间，但这一早熟特性并不受水分亏缺的调控。进一步针对携带HsDry2.2位点分离的BC2F1株系分析显示，野生等位基因在植株籽粒产量、籽粒数、收获指数，以及改良地上部形态、延长籽粒灌浆期与降低衰老（仅在干旱条件下）方面均优于栽培等位基因，这表明其存在除避旱之外的抗旱适应机制。本研究凸显了评估作物野生近缘种以挖掘新型等位基因、解析作物适应非生物胁迫的抗逆机制的重要价值。