Effect of drought stress and plant density on yield, yield components and some morphological characters of pinto bean (cv. C.O.S16) in Yasouj region

In order to evaluate the effects of drought stress and plant density on yield, yield components and morphological characters of pinto bean (Phaseolus vulgaris L.) C.O.S16 cultivar, a field experiment was conducted in split plot arrangement based on a randomized complete block design with three replications in research field of Yasouj University during 2010. Experimental treatments were pinto bean plant density at four levels (15, 25, 35 and 45 plants per square meter)as subplots and drought stress at three levels (in growth stage, reproductive stage after 90 mm evaporation from class A, evaporation basin and common irrigation) as main plots. Result showed that there were significant interaction between drought stress and plant density on characters such as 100 grain weight, plant height, number of branches per plant, harvest index, biological and grain yield. Maximum biological and grain yield recorded at 35 plant.m² treatments in normal irrigation (11235 and 3368 kg.ha^-1 respectively), that was not significant difference in 45 plant.m² treatment. 15 and 35 plant.m² density had the maximum and minimum of grain yield and water use efficiency respectively, under drought stress in growth and reproductive stages. In general, 35 plants per square meter in without stress and 25 plant/m² densities in all water stress levels, had maximum yield for this pinto bean cultivar.