Document Type : Research paper
Authors
1
Department of Biology, Payame Noor University, Tehran, Iran
2
Seed and Plant Improvement Institute, Agricultural Research Education and Extension Organization (AREEO). Karaj. Iran
3
Department of Biology, Payame Noor University, Tehran
4
Seed and Plant Improvement Institute. Agricultural Research Education and Extension Organization (AREEO). Karaj. Iran
Abstract
Okra (Abelmoschus esculentus), a nutritionally valuable crop, is highly susceptible to drought stress, which significantly impacts its yield and quality, necessitating research into mitigation strategies. During the 2021-2022 growing season, a field experiment was conducted at the Seed and Plant Improvement Institute in Karaj, Iran, to assess the effects of water stress on quantitative and qualitative traits of 15 okra genotypes (G1-G15). A split-plot design in a randomized complete block (RCBD) with three replications was employed, comparing two irrigation regimes: optimal (5-day interval) and severe stress (10-day interval). Water stress significantly affected various plant traits, as evidenced by the high coefficients of variation, indicating genetic diversity in stress responses. Under non-stress conditions, genotypes G1, G2, G7, and G10 with fruit yields of approximately 14.87, 19.09, 16.61, and 16.54 t ha-¹, respectively. However, severe water stress resulted in substantial yield reductions in these genotypes (approximately 67.3%, 48.9%, 28.83%, and 27.08%, respectively). Conversely, genotypes G9 and G11 showed relatively lower yield reductions, with G9 maintaining a yield of approximately 7.39 tha⁻¹ under water stress (1.62%reduction) and G11 yielding around 7.99 tha⁻¹ (2.0%reduction), suggesting drought tolerance.Genotype G10 demonstrated notable performance under water stress, yielding 12.06 tha⁻¹ with a 27.0% reduction. Under non-stress conditions, fruit and biological yields were positively correlated with vegetative growth indices and fruit traits, but these correlations weakened under water stress. Principal component analysis (PCA) highlighted variations in trait associations and their contributions to variability between the two water regimes. Cluster analysis revealed distinct genotypic groupings under both irrigation conditions.
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