Abstract

With regards to the importance of drought stress and genotype screening under stress conditions, the current study was conducted to evaluate barley varieties in response to drought stress and find the tolerant ones, along with the determination of the influential ratio of each yield component on grain yield under both conditions. Accordingly, 25 barley varieties were evaluated under two water regimes including 100% (normal condition) and 50% (drought stress) of field capacity. Cluster analysis grouped the genotypes into four and three clusters under normal and stressful conditions, respectively, indicating that drought might limit the phenotypic variability among the verities. Based on the feature selection, spike weight, leaf area, and grain number per spike under normal condition, and the number of fertile spikelets and grain number per spike under water deficit conditions were the most influential traits on grain yield which verifies the impact of drought on the relationship among the agronomic traits. The overall results of biplot showed that varieties Danesiah, Eram, and Yoosef, which had higher grain yield than average for both conditions, were suitable varieties in order to be screened for both normal and drought stress conditions. Finally, according to the results of correlation of tolerance indices with grain yield, stress tolerance index (STI), harmonic mean productivity (HMP), and mean productivity (MP) which showed high correlations with grain yield under both conditions can be introduced as proper indices for screening tolerance genotypes of barley.

摘要

针对干旱胁迫和胁迫条件下基因型筛选的重要性，本研究旨在评估响应干旱胁迫的大麦品种并寻找耐受性，并确定各产量成分对粮食产量的影响比。在这两种情况下。因此，在两种水分条件下对 25 个大麦品种进行了评估，包括 100%（正常条件）和 50%（干旱胁迫）的田间容量。聚类分析分别在正常和压力条件下将基因型分为四个和三个聚类，表明干旱可能限制了基因型之间的表型变异。基于特征选择、穗重、叶面积、正常条件下每穗粒数，缺水条件下的可育小穗数和每穗粒数是对粮食产量影响最大的性状，验证了干旱对农艺性状之间关系的影响。双标图的总体结果表明，在两种条件下的谷物产量均高于平均水平的品种 Danesiah、Eram 和 Yoosef 是适合在正常和干旱胁迫条件下进行筛选的品种。最后，根据耐性指数与籽粒产量的相关性结果，可适当引入在两种条件下均与籽粒产量呈高度相关的胁迫指数（STI）、调和平均生产率（HMP）和平均生产率（MP）筛选大麦耐受基因型的指标。