Evaluation and Comparison of Chitti bean Genotypes under Drought Stress Conditions

Due to the water resources limitation required for agriculture in Iran, providing effective methods to reduce the negative effects of drought on crop yield is one of the important studies to plant breeding. Drought tolerance in crops is very important. By using different cultivars of crops that are able to produce relatively good yield in drought stress, they can be grown with more confidence in arid and semi-arid regions.

In order to evaluation genotypes of chitti bean based on tolerance and susceptibility indices, experiments were conducted in two environments without stress and drought stress in 2016-17 at research farm of Bean Research and education, Khomein. 24 genotypes of chitti beans along with Ghaffar cultivar as control (25 genotypes in total) were compared in Latis design with two replications. In this study, mean productivity index, geometric mean productivity index, stress tolerance index, stress susceptibility index and tolerance index were evaluated.

Drought stress reduced evaluated properties, significantly. Among the genotypes of chitti beans in optimal irrigation and drought stress conditions, KS21578 genotype had the highest grain yield with 2805 and 1719 kg ha-1, respectively. The lowest grain yield were achieved at KS21591 and KS21596 genotypes in optimal irrigation and drought stress conditions, respectively. Due to drought stress, grain yield of evaluated genotypes decreased by 49.1%. Drought stress has increased flowering and maturity periods in genotypes. The highest mean productivity index (1086.6), geometric mean productivity index (2124.8) and stress tolerance index (2054.2) belonged to KS21578 genotype. Also, the highest and lowest tolerance index (respectively, 1288.6 and 126.4)  was observed in Ghaffar cultivar (control) and KS21591 genotype, respectively. Also, the lowest stress susceptibility index (0.2) was obtained in KS21585 genotype.

Totally, based on chitti bean grain yield under normal irrigation and drought stress conditions and evaluation of stress tolerance indices as well as two-way diagram of geometric mean production indices and stress susceptibility index and considering maturity period, plant form and grain marketing 8 chitti bean genotypes were selected for advanced testing.