mitigating the effects of drought stress by applying levels of zeolite on yield, pigments, and some physiological traits of sesame cultivars

Objective: drought stress is a significant environmental factor that impacts the yield and quality of the sesame crop. this study was conducted to examine the effects of drought stress and zeolite on the yield, quantity, and some physiological traits of sesame cultivars.methods: the experiment followed a split-plot factorial design based on a randomized complete block design with three replications. it was conducted at two research locations: the research institute of zabol, zabol, iran, and the agricultural and natural resources research center of baluchestan, iranshahr, iran. the main plots consisted of three drought-stress conditions: full irrigation (according to the irrigation scheme of the area), irrigation cut-off at 50% flowering, and irrigation cut-off at 50% seed filling. the sub-factors included factorial combination of three sesame cultivars (halil, dashtestan, and darab) and four zeolite levels (0, 3, 6, and 9 tons per hectare). zeolite was mixed with the soil before planting. the traits measured included grain yield, biomass, oil percentage, pigments, soluble carbohydrates, proline, and protein.results: the amount of chlorophyll a and chlorophyll b decreased with increasing drought stress intensity; however, the application of zeolite mitigated the adverse effects of drought stress. under irrigation cut-off at 50% flowering, total soluble carbohydrates significantly increased compared to the non-stress conditions. also, leaf proline increased in both locations with increasing drought severity; however, the application of zeolite generally reduced the proline content. under the 50% irrigation cut-off during flowering, the protein level decreased compared to full irrigation. the highest protein content and grain yield were obtained in the halil cultivar at the iranshahr location under non-stress conditions and with the application of nine tons/ha of zeolite. however, in zabol, the highest grain yield was obtained by the darab cultivar at all irrigation conditions, with the application of nine tons of zeolite. generally, grain yield and oil content declined with increasing drought stress, but zeolite application mitigated the drought effects.conclusion: the use of zeolite in the sesame production was beneficial due to its positive impact on reducing the adverse effects of drought stress. also, the darab cultivar may be suggested for the sesame production in zabol, while the halil cultivar seemed more suitable for the iranshahr location.