Mosalam Mohamed, Nemr Rahma A, Aljabri Maha, Said Alaa A, El-Soda Mohamed
Department of Plant Breeding, Hochschule Geisenheim University, 65366, Geisenheim, Germany.
Department of Genetics, Faculty of Agriculture, Cairo University, Giza, 12613, Egypt.
BMC Plant Biol. 2025 Apr 1;25(1):408. doi: 10.1186/s12870-025-06413-0.
Wheat is a major global crop, and increasing its productivity is essential to meet the growing population demand. However limited water resources is the primary constraint. This study aimed to identify genetic factors associated with drought tolerance using a diverse panel of 287 wheat genotypes evaluated under well-watered and drought-stressed conditions. Water Use Efficiency (WUE) and Grain Yield (GY), along with drought tolerance indices, were assessed. A genome-wide association study (GWAS) using 26,814 high-density SNP markers identified loci linked to these traits, with 768 SNPs showing significant associations. Additionally, genomic selection (GS) was performed using the rrBLUP model to predict trait performance across environments.
Among the 768 significant SNPs associated with the measured traits at -log10 (P) ≥ 3, 81 SNPs were mapped with a higher threshold -log10 (P) ≥ 4, indicating pleiotropic and QTL-by-environment interaction effects. Several novel and known genes, previously reported to have functions related to biotic and abiotic stresses response were linked to significant SNPs. Among the drought indices evaluated, stress tolerance index (STI), geometric mean productivity (GMP), and tolerance index (TOL) were the most reliable indicators for selecting stable, high-yielding genotypes under drought and control conditions. The same three indices exhibited high prediction values under the severe drought stress (SS) condition. Five genotypes were identified as promising candidates for breeding programs based on their superior drought tolerance, high grain yield, and nutritional value.
This study provides valuable insights into the genetic basis of drought tolerance in wheat, highlighting key SNPs and genomic regions associated with improved water use efficiency and yield stability. The findings contribute to the development of drought-tolerant wheat varieties with optimized water utilization to achieve increased yield per unit of water at diverse water levels, ultimately contributing to sustainable agriculture and food security.
小麦是全球主要作物，提高其生产力对于满足不断增长的人口需求至关重要。然而，有限的水资源是主要限制因素。本研究旨在通过在充分灌溉和干旱胁迫条件下对287个不同小麦基因型进行评估，确定与耐旱性相关的遗传因素。评估了水分利用效率（WUE）和籽粒产量（GY）以及耐旱性指标。使用26,814个高密度SNP标记进行全基因组关联研究（GWAS），确定了与这些性状相关的位点，其中768个SNP显示出显著关联。此外，使用rrBLUP模型进行基因组选择（GS），以预测不同环境下的性状表现。
在与测量性状相关的768个显著SNP中，-log10（P）≥3时，有81个SNP以更高的阈值-log10（P）≥4进行定位，表明存在多效性和QTL与环境的互作效应。几个先前报道与生物和非生物胁迫反应相关的新基因和已知基因与显著SNP相关联。在评估的干旱指标中，胁迫耐受指数（STI）、几何平均生产力（GMP）和耐受指数（TOL）是在干旱和对照条件下选择稳定、高产基因型的最可靠指标。在严重干旱胁迫（SS）条件下，相同的三个指标表现出较高的预测值。基于其优异的耐旱性、高籽粒产量和营养价值，鉴定出五个基因型作为育种计划的有前景候选材料。
本研究为小麦耐旱性的遗传基础提供了有价值的见解，突出了与提高水分利用效率和产量稳定性相关的关键SNP和基因组区域。这些发现有助于开发具有优化水分利用的耐旱小麦品种，以在不同水分水平下实现单位水分产量的增加，最终为可持续农业和粮食安全做出贡献。
