Effects of deficit irrigation on yield and yield components of pinto bean genotypes in Shahrekord

Introduction Pinto bean (Phaseolus vulgaris L.) is one of the most important bean types in Iran. Cultivation area of pinto bean is about 50% of total bean cultivation area and more than half of grain bean production belongs to this type of bean. Drought is the most important environmental stresses that affects agricultural production in arid and semiarid areas and reduces crop productions. According to FAO reports, 90% of cultivation area in Iran is under arid and semi-arid conditions, so water deficit severely affects crop quantity and quality of most crop. About 60% of bean cultivation area in the world are faced with drought. Bean yield loss due to drought stress depends on severity and duration of stress and genetic variations of genotypes. Bean yield components such as grain weight, grain number per plant and pod number per plant decrease by drought stress. According to the 15 bean genotypes evaluation in favorable moisture conditions and water deficit, there were significantly differences between genotypes for most of yield related traits. Due to limited water resources in the Iran, evaluation of bean genotypes under water stress is important. So this study was conducted to evaluate the changes in yield and yield components of pinto bean genotypes under deficit irrigation conditions. Material and Methods An experiment as split plot in randomized complete block design base was conducted for evaluation of effect of deficit irrigation at three levels (supply of 100, 80 and 60 percent of crop water requirement as main plot) on pinto bean genotypes in five levels (Taylor, Sadri, C.O.S.16, KS21193(Koosha193) and KS21486 as sub plot) in Shahrekord university. Before planting, seeds were disinfected with Benomyl fungicide. Then planting was conducted in 30 plant m-2 density.Crop water requirements calculated by Penman-Monteith equation amended by FAO. Irrigation treatments was applied at beginning of V4 stage (unfolding of third trifoliate leaf) and continued in the growing season. At the end of experiment one square meter of each plot harvested and yield and yield components were measured. Data were analyzed in SAS software (version 9.1). Slicing method was used for interaction mean comparison. Results&Discussion The effects of irrigation regime, genotype and the interaction of irrigation regime and genotype on unfertile pod number, unfertile pod weight, Fertile pod number, fertile pod per plant, grain number, grain weight, biological yield, grain yield and