Yield and Physiological Response of Red Bean Genotypes (Phaseolus vulgaris L.) to Cutting Irrigation off at Different Growth Stages

Water deficit and graduall reduction of available water resources are the limiting factors of crop production. To investigate the effect of water deficit stress on yield and components of some red bean genotypes a split plot experiment in the form of randomized complete block design with three replications was carried out at the Agricultural Research Station of Islamic Azad University, Arak Branch. The treatments consisted of full irrigation (control), cutting irrigation off during flowering stage, cutting irrigation off of pod filling stage and three genotypes of red bean (derakhshan, goli, and D81083). The results showed that the effect of cutting off irrigation during the growth stages on biological yield, grain yield, harvest index, number of pods per plant, number of seeds per pod was significant. The results also showed that the highest seed yield belonged to the full irrigation (control) treatment, where D81083 and goli produced higher yields than derakhshan. Highest grain yield was belonged to goli at full irrigation (control) treatment. Among the genotypes under study, D81083 had the lowest amount of reduction equal to 60 percent during cutting off irrigation at flowering stage. Number of seeds per pod decreased when irrigation was cutted off during the flowering stage. Derakhshan produced higher yield than the other genotypes and its seed per pod decreased by 38 percent. The results also revealed that red bean genotypes were very sensitive to deficite water stress. As a whole D81083 and goli genotypes were higher yielders than Derakhshan under limited water conditions.