Physiological Basis of Yield in Moth Bean [Vigna aconitifolia (Jacq.) Marechal] Under Rainfed Conditions

Physiological analysis of yielding ability in moth bean varieties under rainfed condition revealed that in spite of sufficient amount of dry matter production, the crop is a poor seed yielder. Late varieties produced higher amounts of dry matter and seed. The low yield in this crop is owing to low net assimilation rate (NAR) during the reproductive phase and poor migration coefficient of assimilates towards seeds. Leaf area expansion was maximum during reproductive phase. Stomatal components were not evident to limit the NAR under rainfed condition. Varietal differences were observed with respect to transpiration. Temporal variations in leaf water potential, osmotic potential and pressure potential were recorded. It is concluded that in moth bean the improvement in seed yield is possible by increasing current photosynthetic rate during the reproductive phase and can be achieved by changing the crop canopy structure for better utilization of light. Effort should also be made to improve harvest index in this crop.