Grain yield efficiency index, a criterion for selecting the best bean genotypes in drought stress conditions

Identification of bean genotypes in terms of water use efficiency is important in developing a breeding program to improve cultivars efficient in water use under water deficit conditions. Different indicators are used to better understand the response of cultivars to water scarcity. One of the indicators that can help in selecting the best genotypes under stress conditions is the yield efficiency index. Therefore, to determine the yield, yield components and efficiency index of beans under water deficit condition, this experiment was performed as split plots in a randomized complete block design with four replications. Irrigation conditions (normal and stress) in the main plots and eight bean genotypes in the sub-plots were investigated. Analysis of variance of traits showed that growth period, yield and yield components were significantly different in the evaluated genotypes. Water deficit stress reduced grain yield of genotypes by 47%. AND1007 and COS16 genotypes had the highest grain yield efficiency index, respectively. These two genotypes, along with MCD4011 and WA4502-1, were classified as efficient water consumers. Based on susceptibility and resistance indices, the best genotypes were AND1007, COS16 and MCD4011. In general, the grain yield efficiency index is a good criterion for determining the response of bean genotypes to water deficit stress. Cultivars that produce higher yields under stress conditions and respond well to optimal irrigation are the most desirable genotypes because they are able to maintain their high yield potential over a wide range of available water.