Assessment of physiological traits of common bean cultivars in response to water stress and molybdenum levels

Abstract

Molybdenum is an essential micronutrient that regulates plant growth, development, and responses to abiotic environmental stresses. However, little is known about the joint effects of water stress, molybdenum, and cultivar on physiological traits of field-grown common bean. Therefore, a split-plot factorial design was used to determine the main and interaction effects of Water stress (3 levels: 55–60, 90–95 and 120–125 mm evaporation from class A pan), Molybdenum (2 levels: control and 80 g per ha), and Cultivar (2 levels: Akhtar and COS-16) on physiological traits and grain yield of common bean. The results indicated that leaf area index (LAI), chlorophyll index, relative water content (RWC) and grain yield decrease with increasing water stress. Spraying molybdenum to the plants increased LAI, RWC, and grain yield, but the extent of the increase varied with cultivar. The positive effect of molybdenum also varied with the magnitude of water stress, and it was higher in severe water stress condition compared to that in normal irrigation and moderate water stress conditions. Of the two cultivars, COS-16 gave significantly higher grain yield than Akhtar cultivar, but Akhtar was superior in terms of physiological traits. The study demonstrated that the application of Molybdenum under water stress may cause an increase in N uptake and the efficiency of its use, that consequently increases the chlorophyll index and grain yield of common bean cultivars.