Agrophysiological response of cotton to foliar application of stress modulators in early and delayed planting date

In order to investigate the agrophysiological response of cotton to foliar application of stress modulators in different planting date, an experimental was conducted as split-plot factorial in a randomized complete block design with three replications in 2017-2018. Factors were: planting date (early (May 15 and 20, for the first and second year, and late (June 20 and 17, for the first and second year, respectively) as the main plot and type of stress modulator at four levels (control, salicylic acid, glycine betaine and sodium nitroprusside) and time of stress modulators application (flowering and flowering + bolling stage) as a factorial in the sub-plot. Both in early and late planting date, foliar application in flowering+bolling stage increased the number of reproductive branches, number of bolls per plant, seed cotton and lint yield. The highest number of bolls per plant was obtained in early planting date by foliar application of glycine betaine (15.7) and in late planting date by foliar application of salicylic acid (8.7). While salicylic acid foliar application increased the seed cotton yield in early planting date (47%), but in late planting date, seed cotton yield did not respond to the stress moderator application. In both flowering and flowering+bolling stage, the highest seed cotton yield was obtained by spraying sodium nitroprusside (1265 and 1537 kg/ha, respectively). In terms of lint and seed yield, in early planting date, foliar application of sodium nitroprusside and in late planting date, foliar application of salicylic acid was better than other modifiers. Overall, the results of this experiment showed that sowing at the appropriate date and foliar application with salicylic acid in the flowering + bolling stage is the most appropriate treatment to obtain the highest seed cotton yield in saline condition.