Determination of the effects of drought stress and plant growth regulators on the agronomic, physiological and enzymatic traits of chickpea (Cicer arietinum l.)

This research was carried out in the greenhouse of the Department of Field Crops, Faculty of Agriculture, Dicle University, during the spring growing season of 2025. This study was conducted to determine the effects of gibberalic acid and abscisic acid applications on the vegetative and physiological characteristics of Botan and ICC 4958 chickpea varieties exposed to drought treatment during the pod formation period. Experiments consisted of 1- 100% and 50% field capacity, 2- 100%-50% field capacity + abscisic acid application, 3- 100%-50% field capacity + GA3 application and 4- abscisic acid and gibberellic acid 14-day drought treatment. The experiment was conducted in randomized plots according to a split-plot design with 6 replications. 4.5 kg pots were used in the experiment. All pots were irrigated at 100-50% field capacity until the first pod formation. Starting from the first pod formation date, 14 days of drought and plant growth regulators were applied to the pots. Plants were harvested after a 14-day drought treatment. Plant height, root length, number of nodes, number of nodules, fresh and dry weights of stems, leaves, and roots, leaf area, number of live and dead flowers, number of pods and grains per plant, drought score, estimated yield reduction and drought resistance index, leaf relative water content, leaf wilt score, plant greenness, and leaf wilt index were observed and measured. Differences among drought treatments, plant growth regulators, and cultivars, as well as their interactions, were found to be significant. It was determined that 14-day drought treatments caused a decrease in all studied traits, including plant growth regulator treatments. Drought score, plant greenness, and leaf wilt scores were lower in the 100% TK continuous irrigation and higher in the 50% TK 14-day drought treatment. The drought score in the ABA and GA3 treatments was lower than the control. The number of live flowers was found to be higher in 100% TK continuous irrigation, lower in 50% TK 14-day drought treatment, and higher in gibberellic acid treatment than ABA. It was found that the number of nodules was higher in 100% and 50% TK continuous irrigation (55.6 and 52.8, respectively), and lower in 100% and 50% TK 14-day drought treatments (22.0 and 20.0, respectively). The number of nodules of ABA (67.6) was found to be higher than GA3 (47.1) and control (41.0). In ICC 4958, the highest nodule number was determined in ABA with 103.7 pieces at 50% field capacity. Nodule number was not determined in 14-day drought treatment. The highest value in root dry weight was obtained from 100% and 550 TK 14-day drought treatments. Both varieties and plant growth regulators were found to have low values after 14 days of drought irrigated to 50% field capacity until pod set. ABA and GA3 growth regulators were found to have some positive effects in overcoming drought. This study determined that Botan, as well as ICC 4958, has high drought tolerance.