Mitigation of Drought Stress by Foliar Application of Salicylic Acid and Potassium Chloride in Cluster bean (Cyamopsis tetragonoloba L.)

Background: Plant growth is often affected with hampered physiological and cellular functioning due to salinity and drought stress. To investigate the effectiveness of plant bioregulator (i.e. salicylic acid-SA) and potassium chloride (KCl) in mitigating abiotic stresses in cluster bean, a field experiment was conducted in rainy season from 2018 to 2020 at Agricultural Research Station, Fatehpur-Shekhawati (Sikar), Rajasthan. Methods: The experiment was laid out in randomized block design with seven treatments and three replications. Total seven treatments consisted in experiment viz.,T1: Control (no SA and KCl application); T2: SA 100 ppm; T3: SA 200 ppm; T4: SA 300 ppm; T5: KCl 0.5%; T6: KCl 1.0%; T7: KCl 1.5%.These foliar application of treatments were applied twice during season, first at flowering and second at pod formation stage. Result: The results revealed that the foliar application of SA from 100 to 300 ppm and KCl from 0.5 to 1.5%, significantly improved all physiological, growth and yield parameters of cluster bean during the experimentation. In cluster bean, the maximum pooled leaf fresh, dry and turgid weight (2.37, 0.645 and 3.26 g) were recorded under the foliar application of salicylic acid@ 300 ppm, respectively. Similar results were also reported with higher relative leaf water content (65.98%), cell membrane stability (84.66%) and lowest transpiration rate (5.16 mg/g fw/m). Among the growth parameters the highest plant height (81.33 cm), number of branches per plant (12), number of clusters per plant (41), number of pods per cluster (5),number of pods per plant (194) and number of seeds per pod (7.67) were recorded with treatment foliar application of salicylic acid@ 300 ppm. Similarly, the yield parameters viz. test weight (34.84 g), grain yield (15.54 q ha-1), stover yield (37.53 q ha-1) and harvest index (31.33%) were also recorded higher with the application of salicylic acid @ 300 ppm in cluster bean, which were 1.46, 19.69, 17.50 and7.41% higher over control.