Behnam Tahmasebpour; Sodabeh Jahanbakhsh; Ali Reza Tarinejad; Hamid Mohammadi; ali ebadi
Abstract
Objective: This study aimed to investigate the relationships between traits and use these relationships to select high-Objective: Wheat, accounting for about 20% of global cultivated land, is vital for food security. With over 90% of Iran classified as arid or semi-arid, drought stress critically impacts ...
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Objective: This study aimed to investigate the relationships between traits and use these relationships to select high-Objective: Wheat, accounting for about 20% of global cultivated land, is vital for food security. With over 90% of Iran classified as arid or semi-arid, drought stress critically impacts crop yields, causing approximately 17% losses annually. Improving drought resilience and water-use efficiency in wheat is therefore essential. This study aims to assess drought tolerance in bread wheat genotypes based on their performance under normal and water-stressed conditions, and to identify morphological, phenological, and physiological traits linked to high yield for use in breeding programs.Methods: A split-plot experiment with three replications was conducted in a greenhouse to evaluate 30 wheat genotypes under normal irrigation and post-anthesis drought stress. Trait correlations, yield associations, and the relative importance of traits were analyzed using ANOVA, mean comparisons, cluster analysis (Euclidean distance and Ward’s method), and factor analysis.Results: Cluster analysis grouped genotypes into four under normal conditions, with the first group (including cd-6, c-93-8, cd-3, etc.) exhibiting the highest average grain yield of 7.93 g per five plants. Under drought, the second group (Mihan, Eroum, c-93-3, etc.) achieved the highest yield of 2.18 g per five plants. The first two principal components explained 76.24% of data variability, effectively distinguishing sensitive cultivars (C-93-11, C-93-4) and drought-tolerant genotypes (Mihan, Eroum). Biplot analysis identified flag leaf area, vegetative growth rate, fertile tiller number, grain yield, grains per spike, and 1000-grain weight as key traits for genotype separation under both conditions.Conclusion: According to results, the first and second two components explained 76.24% of the changes in the primary data, that the morphological and physiological traits could be determined by the sensitive cultivars (C-93-11 and C-93 4) and separate the drought tolerant (Mihan and Eroum) from each other. Based on the results of Biplot analysis, flag leaf area, vegetative growth rate, number of fertile tillers, grain yield, number of grains per spike and 1000-grain weight had a determinative role in isolating genotypes under normal irrigation and stress conditions..