The Effect of Yeast Extract on Physiological and Biochemical Indicators of Cowpea in Drought ‎Stress Conditions

In order to investigate the role of foliar application of yeast extract on physiological and Biochemical properties of cowpea (Vigna sinensis L.) under drought stress conditions, a factorial experiment has been conducted as a randomized complete block design with three replications in Agriculture Campus of Shahrood University of Technology (located in Bastam) during 2017 under drought stress and foliar application of yeast extract. Drought stress involves two stages of 50 present flowering and 50 present pod formation with control treatment (without irrigation interruption). Foliar application of yeast extract (two, four, six g/L, and control) are repeated twice with a seven-day interval, with the first one being 30 days after planting. Results show that drought stress has decreased relative water content of leaves. In contrast, relative water content (5.82%), proline content (30.74%), leaf flavonoid (83%), nitrogen (3.82%), phosphorus (22.22%), and potassium (43%) are among the traits that have increased with the use of yeast extract, compared to the control. Six g / L of the yeast extract has increased grain yield (1.02 t ha-1), leaf anthocyanin (0.072 mg /g fresh weight), and proline (31.62 mg /g fresh weight). It can be said that a concentration of six g/L of yeast extract can be useful to reduce the severity of drought stress. The yeast extract can act as an ecological strategy to improve the defensive response against environmental stresses.