DEVELOPMENT OF MUNG-BEAN SEED VIGOUR UNDER DIFFERENT IRRIGATIONS AND PLANT DENSITIES
Production and cultivation of vigorous seeds are essential for improving stand establishment and crop yield under different environmental conditions. Thus, a field experiment was carried out as split plot based on RCB design with three replications in 2013 to determine the best developmental stage of mung-bean seeds under different water supply (I1, I2, I3, I4 for irrigation after 70, 100, 130 and 160 mm evaporation from class A pan, respectively) and plant densities (D1, D2 and D3for 30, 50 and 70 plants/m2, respectively). Seeds were harvested at five day intervals in eight stages. Mass maturity (end of seed filling phase) under I1 for all densities was achieved at 1300 GDD, but under I2, I3 and I4 it was occurred at 1200 GDD for30 plant/m2 and at about 1100 GDD for 50 and 70 plant/m2. Maximum seed vigour as measured by germination rate, electrical conductivity of seed leachates and seedling dry weight was obtained at about mass maturity or 100 - 200 GDD after this stage, depending on densities and irrigation treatments. Seed moisture content at this stage was about 20%. Therefore, it was concluded that high vigour seeds of mung-bean can be produced under various environments, provided the seeds are harvested at about 20% moisture content.