Genetics Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt.
Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
PeerJ. 2024 Sep 26;12:e18104. doi: 10.7717/peerj.18104. eCollection 2024.
Wheat, a staple cereal crop, faces challenges due to climate change and increasing global population. Maintaining genetic diversity is vital for developing drought-tolerant cultivars. This study evaluated the genetic diversity and drought response of five wheat cultivars and their corresponding F1 hybrids under well-watered and drought stress conditions. Molecular profiling using ISSR and SCoT-PCR markers revealed 28 polymorphic loci out of 76 amplified. A statistically significant impact of parental genotypes and their crosses was observed on all investigated agro-morphological traits, including root length, root weight, shoot length, shoot weight, proline content, spikelet number/spike, spike length, grain number/spike, and grain weight/spike. The parental genotypes P1 and P3 had desirable positive and significant general combining ability (GCA) effects for shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, shoot length, and root length under well-watered conditions, while P3 and P5 recorded the highest GCA estimates under drought stress. P3 and P4 showed the highest GCA effects for number of spikelets per spike, the number of grains per spike, and grain weight per spike under normal conditions. P5 presented the maximum GCA effects and proved to be the best combiner under drought stress conditions. The cross P1× P3 showed the highest positive specific combining ability (SCA) effects for shoot fresh weight under normal conditions, while P2×P3 excelled under water deficit conditions. P1× P2, P1 × P3, and P4× P5 were most effective for shoot dry weight under normal conditions, whereas P1×P3 and P3×P5 showed significant SCA effects under drought stress. Positive SCA effects for root fresh weight and shoot length were observed for P3×P5 under stressed conditions. Additionally, P4×P5 consistently recorded the highest SCA for root length in both environments, and P3×P5 excelled in the number of spikelets, grains per spike, and grain weight per spike under drought conditions. The evaluated genotypes were categorized based on their agronomic performance under drought stress into distinct groups ranging from drought-tolerant genotypes (group A) to drought-sensitive ones (group C). The genotypes P5, P2×P5, and P3×P5 were identified as promising genotypes to improve agronomic performance under water deficit conditions. The results demonstrated genetic variations for drought tolerance and highlighted the potential of ISSR and SCoT markers in wheat breeding programs for developing drought-tolerant cultivars.
小麦是一种主要的谷类作物，但由于气候变化和全球人口增长，它面临着挑战。保持遗传多样性对于培育耐旱品种至关重要。本研究在充分供水和干旱胁迫条件下，评估了五个小麦品种及其相应 F1 杂种的遗传多样性和干旱响应。使用 ISSR 和 SCoT-PCR 标记的分子谱分析显示，在 76 个扩增产物中，有 28 个多态性位点。亲本基因型及其杂交对所有调查的农艺形态性状，包括根长、根重、茎长、茎重、脯氨酸含量、小穗数/穗、穗长、穗粒数/穗和穗粒重/穗，均有显著的影响。在充分供水条件下，亲本基因型 P1 和 P3 对茎鲜重、茎干重、根鲜重、根干重、茎长和根长具有理想的正显著一般配合力（GCA）效应，而 P3 和 P5 在干旱胁迫下记录了最高的 GCA 估计值。在正常条件下，P3 和 P4 对每个小穗的小穗数、每个小穗的粒数和每个小穗的粒重表现出最高的 GCA 效应。P5 表现出最高的 GCA 效应，在干旱胁迫条件下被证明是最好的组合。在正常条件下，P1×P3 对茎鲜重表现出最高的正特殊配合力（SCA）效应，而 P2×P3 在水分亏缺条件下表现出色。在正常条件下，P1×P2、P1×P3 和 P4×P5 对茎干重的 SCA 效应最高，而 P1×P3 和 P3×P5 在干旱胁迫下表现出显著的 SCA 效应。在胁迫条件下，P3×P5 对根鲜重和茎长表现出正 SCA 效应。此外，在两种环境下，P4×P5 始终记录到根长的最高 SCA，而 P3×P5 在小穗数、每穗粒数和每穗粒重方面表现出色在干旱条件下。根据它们在干旱胁迫下的农艺表现，对评价的基因型进行分类，分为耐旱基因型（A 组）和耐旱基因型（C 组）。基因型 P5、P2×P5 和 P3×P5 被确定为在水分亏缺条件下提高农艺表现的有前途的基因型。结果表明，小麦具有耐旱性的遗传变异，并强调了 ISSR 和 SCoT 标记在小麦育种计划中用于培育耐旱品种的潜力。
