Evaluation of genetic diversity in land races of bread wheat under irrigated and rainfed conditions

ABSTRACT: In order to investigate genetic diversity and drought resistance of 30 bread wheat genotypes an experiment was conducted in a randomized complete block design (RCBD) with three replications under irrigated and rainfed conditions at College of Agriculture, Razi University, Kermanshah, Iran during 2010-2011. Analysis of variance and mean comparisons revealed significant differences between the genotypes in both conditions. Mean values showed that all of the agronomic and phenological traits responded to drought stress because their means values decreased in stress condition. The most productive genotype in stress condition was number 17 (WC-5001) (6.21 ton/ha), while number 15 (WC-47615) was the least productive. In non-stress condition genotype number 25 (Pishgam) was the most productive (7.80 ton/ha), while number 6 (WC-47578) was the least productive. Correlation analysis in drought stress condition indicated positive significant correlation between grain yield with thousand seed weight (TSW), number of spikes per m2 (NSP), harvest index (HI) and biological yield (BY), wherease exhibited negative significant correlation between grain yield with days to flowering (DF= earliness) and plant height (PH). Correlation coefficients in non-sress condition displayed positive significant correlation between grain yield with number of seeds per spike (NSPS) and thousand seed weight (TSW). Cluster analysis using Ward method based on yield and yield components, morphological and phenological characteristics classified genotypes in stress and non-stress conditions in three groups. The grouped accessions in both conditions were very similar with some minor dissimilarity. The results indicated a high genetic diversity among the genotypes under investigation.