Genetic variability of yield and morphological traits in several populations of two Bromus species (B. tomentellus and B. persicus)

In order to study the genetic variability of two Bromus species, B. tomentellus and B. persicus, based on morphological traits, 12 populations were examined in a field experiment using a randomized complete block design with 3 replications during 2006-2008 in Karaj, Iran. The data were collected for heading date, plant height, tiller number, panicle length, seed weight and seed number per panicle, forage dry matter yield, seed yield, thousand grain weight and harvest index. Results showed that B. persicus populations had higher values than B. tomentellus for all the traits except for thousand grain weight. Population 68 of B. persicus with average values of 7157 and 1059 Kg/ha showed higher forage and seed production, respectively. Phenotypic correlation between forage and seed yield was positive and significant. Both traits positively correlated with heading date, plant height and tiller number and negatively correlated with thousand grain weight. Using cluster analysis (Ward method) and principle components analysis (PCA) based on the morphological data, the populations were classified into two groups coordinating to the two species. The distribution of the populations based on (PCA) analysis was in agreement with cluster analysis results.