Promote the Yield and Physiological Traits in Guar (Cyamopsis tetragonoloba L.) by Application of Salicylic Acid and Potassium under Water Stress Conditions

Background: Determination of the most important level of salicylic acid to increase guar yield in drought stress conditions. Methods: In order to study the effect of potassium and salicylic acid on agricultural and physiological traits of guar in different irrigation treatments, a field experiment was conducted during 2020-2021 under the climatic conditions of Jiroft area (Kerman province, Iran) in the farm of research center and agricultural and natural resources education. The experimental treatments include three levels of irrigation (regular irrigation, stress 60 and 80% of the plant's water requirement) in strip plots, three levels of salicylic acid (no application, 0.1 and 0.5 mM) as foliar spraying and two levels of potassium (no application and use of 100% of the plant's need for potassium) in horizontal plots. Result: The results showed that drought stress and application of potassium and salicylic acid had a significant effect on all traits. Decreasing the amount of water led to a decrease in the physiological and functional characteristics of guar compared to regular irrigation. But potassium and salicylic acid were able to improve the yield characteristics and yield of guar under stress and nonstress conditions and the use of potassium + 0.5 mM salicylic acid were introduced as the best treatment for both conditions. This treatment at 60% stress led to an increase in plant height (91%), the number of leaves (37%), the number of pods (85%), seed number (70%), seed yield (100%), chlorophyll a (61%), chlorophyll b (59%) and carotenoid (100%) compared to the control treatment.