The effect of foliar application of plant growth regulators on functional and qualitative characteristics of wheat (Triticum aestivum L.) under salinity and drought stress conditions

Abstract This study aimed to investigate the effect of salinity and water stress on the physiological and functional characteristics of winter wheat ( Triticum aestivum L .) under the foliar application of plant growth regulators (PGRs). The experiment was carried out as a split plot based on a randomized complete block design with three replications in two environments. In each environment, water stress at two irrigation levels (after 90 and 120 mm of pan evaporation) and with two EC of 1.5 and 10 dS/m in the main plots and spraying of PGRs including salicylic acid (SA), gibberellic acid (GA 3 ), and cytokinins (CK) (purine) content with a concentration of 100 ppm and the control treatment (spraying solution with normal water) were placed in subplots. Results indicated that all treatments caused significant increases in functional and qualitative characteristics and yield of Triticum aestivum L . The saline environment and irrigation level after 120 mm of pan evaporation caused a reduction in grain yield in all traits except for seed proline, seed nitrogen content, and seed protein content. Also, the combined foliar application of GA 3 + CK + SA increased yield in most traits. The highest RWC of flag leaves was observed in the foliar application of GA 3 + SA (3.36 kg/ha) and then in the foliar application of GA 3 + SA + CK (57.87 kg/ha). GA 3 interacts with PGR spraying to balance another development under saline and non-saline conditions.