Physiology of fodder cowpea varieties as influenced by soil moisture stress levels

A field experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram during January 2012 to March 2012. Five fodder cowpea varieties (V₁: UPC 618, V₂: UPC 622, V₃: Bundel Lobia-1, V₄: COFC-8 and V₅: CO-5) were evaluated for their drought tolerance under four soil moisture stress levels (M₁: pre-sowing irrigation + lifesaving irrigation, M₂: pre-sowing irrigation + at IW/CPE ratio of 0.4, M₃: presowing irrigation + irrigation at IW/CPE ratio of 0.6, M₄: pre-sowing irrigation + irrigation at IW/CPE ratio of 0.8. The investigation was conducted as two separate experiments, one in open and other in shade situations. Based on the results, it was found that leaf area index, dry matter production, relative water content, leaf water potential and osmotic potential increased at IW/CPE ratio of 0.8 in open and shade conditions. Among the varieties, COFC-8 registered highest values in physiological parameters studied, and it was considered as a tolerant cultivar in water deficit conditions.