Assessing the drought tolerance of some sesame genotypes using agro-morphological, physiological, and drought tolerance indices

Abstract Background One significant abiotic stressor that harms sesame productivity globally is drought. This investigation used six sesame genotypes to measure variance in many variables under irrigated and terminal drought stress environments. Growth characteristics (plant height, fruiting zone length, branches’ number), yield-related parameters (capsules’ number per plant, capsule’s length, 1000 seeds’ weight, seed yield per plant, and seed yield per feddan) and physiological characters (relative water content, chlorophyll A content, chlorophyll B content, chlorophyll A + B content, and proline concentration) of sesame were measured. Six drought indices (geometric mean productivity (GMP), mean productivity (MP), stress tolerance index (STI), tolerance index (TOL), stress susceptibility index (SSI) and, yield stability index (YSI)) were derived using seed yield per feddan. This study was aimed to investigate the effects of drought stress on the physiological and yield-related characteristics of the sesame genotypes and to find the qualities that were most helpful in selecting drought-resistant genotypes. Results The analysis of variance revealed significant differences in genotypes and water depletion ratios, as well as their interactions, for all growth variables, except the interaction between genotypes and water depletion ratios for plant height and relative water content. Line 13 (H. 102) had the highest branches’ number (6.85), capsules’ number per plant (239.33) and capsule’s length (3.35 cm) attributes under normal circumstances. Line 31 (H. 68) produced the maximum yield per plant (33.45 g) and feddan (679.83) and had the highest weight of 1000 seeds (3.9 g) under normal circumstances. Under the level (80% water depletion ratio), H. 68 had the highest amounts of chlorophyll A (5.73) and chlorophyll A + B (17.37) whereas H. 102 exhibited the highest concentration of chlorophyll B (5.73). The genotype H. 68 of sesame was found to have the greatest MP (650.35), GMP (649.32) and YI (1.16) indices followed by genotype H. 102. The Shandaweell 3 genotype resulted in the lowest SSI (36.92) and TOL (0.55) indices. Line 26 (H132) exhibited the highest average YSI values. Conclusions These data revealed that genotypes H. 102, H. 68 and Shandaweell 3 are the most drought-tolerant among the genotypes utilized in this study. These results may contribute to developing effective breeding techniques for drought-stressed sesame in the future.