Comparison of seed yield and related traits in common bean (Phaseolus vulgaris L.) varieties under normal and water deficit conditions

Abstract

The effect of water stress were studied on the agronomic traits related to yield of common bean by planting 32 genotypes in normal and water deficit conditions. These genotypes were evaluated in randomized complete block design with three replications in experimental field of Faculty of Agriculture, University of Tehran, Karaj Campus in 2007. Analysis of variance showed that there were significant differences among varieties in all traits, indicating the existence of genetic variation among varieties. Factor analysis were accomplished in both conditions indicated that there were five factors that explained 73 and 72 percent of total variations in normal and stress conditions, respectively. Path analysis for seed yield showed that number of pods per plant had the highest positive effect, 0.697 and 0.699, respectively, on seed yield in normal and stress conditions. Number of days to podding (0.026) and length of pod (-0.004) had indirect effects through number of pods on seed yield. Also, in stress condition, number of seed per pods (0.083) and 100 seed weight (-0.074) had indirect effects through number of pods on seed yield. Therefore, this trait could be used as an indicator for improving of common bean seed yield. Phenotypic clustering of genotypes (UPGMA) showed that all of the genotypes were classified in four separate groups in normal and stress conditions. Evaluation of drought resistance in common bean genotypes showed that stress tolerance index (STI), geometric mean productivity (GMP) and harmonic mean of yield were the best criteria for reorganization of tolerant genotypes as detected as KS-31127, KS-31150, KS-3138, KS-31139, KS-31112 in this experiment.

Keywords

• cluster analysis
• drought resistance indices
• factor analysis
• path analysis
• water deficit