Evaluation of Water Stress Memory in Compensation Response of Cotton (Gossypium hirsutum L.) during Subsequent Water Deficiency

This research was carried out to provide suitable cotton seed for seed propagation in dryland. In this study, the potential of cotton seeds that have been stressed for the third-consecutive year was investigated to evaluate water stress memory responses. The experiment was arranged in split-plot factorial design with four irrigation levels of W۰ (No- irrigation), W۱ (۳۳% FC), W۲ (۶۶% FC), and W۳ (۱۰۰% FC), as the main factor, and five seed treatments (four third-stressed seeds, i.e. S۲۱ to S۲۴, and registered seed), as a sub-plot. Seeds of cotton were grown under different levels of water-stress exposure for three crop-seasons. As results showed, S۳۲ received water stress signal in both W۰ and W۳ conditions through physiological mechanisms change. Seeds of S۳۲ accumulated the lowest ABA and the highest calcium in exposure to W۰ and W۳. Enhancement to superoxide dismutase and Aspartate peroxidase activity in leaves of S۳۲ in exposure to W۰ and W۱ is another memorial stress mechanism for scarce water acclimation. The highest-potential thirty-boll weight, thirty-fiber weight, and first-harvesting yield were obtained from S۳۲ against W۰, W۱, and W۲.. Also, the seeds of S۳۲ had the most seedling vigor and germination percentage in exposure to W۰, W۱, and W۲. It can be concluded that stress memory, via modification of physiology and morphology of plant behavior, helps plants to tolerate water deficiency when subjected to recurrent drought.

Keywords:

Compensation mechanism , Drought tolerant , Seed , Yield.