Sesame (Sesamum indicum L.) growth properties and yield attributes are associated with potassium level in response to drought stress

Abstract

Little attention is paid to the mitigating effect of different potassium (K) levels on sesame (Sesamum indicum L.) growth performance in response to drought stress (DS). A pot experiment was performed under DS conditions along with four K levels (0, 60, 120 and 180 kg ha−1, denoted as DK0, DK1, DK2 and DK3 respectively), and 120 kg ha−1 of K2O application under normal watering was set as control (CK). Results showed that the plant height, specific leaf weight, leaf water content, chlorophyll content, crop growth rate and biomass were significantly decreased by 6.9%, 15.3%, 7.3%, 17.9%, 55.6% and 34.1%, respectively, as compared to CK whereas K could alleviate the adverse effects of drought on the aforementioned parameters, and the mitigation was more prominent as K rates increased. The decrease in capsule number per plant (1.72 g) primarily accounted for yield loss (1.95 g) induced by DS. Expectedly, K supply compensated for the yield reduction to an extent and the maximum compensation was recorded under DK3, which increased by 50.0% as compared to DK0. Additionally, enhanced yield and yield components were positively correlated with K accumulation as it was further evidenced by significantly increased K uptake in plant tissues. For every extra 1 g of K absorbed by the plant, the yield per plant would increase by 16 g However, the K utilization efficiency showed a downward trend along with increased exogenous K supply under DS. In conclusion, K application at the rate of 120 kg ha−1 is an economical and effective approach for alleviating drought susceptibility in sesame crops.