Investigation on forage yield of several accessions of Elymus pertenuis in dry and irrigated conditions based on drought tolerance indices in Fars Province

In order to study drought tolerance indices and to identify drought tolerant accessions، 16 accessions of Elymus pertenuis were evaluated under dry land and irrigated farming systems using a randomized complete block design with three replications for each environment in a research farm of Hossein Abad، Shiraz، Iran. Five drought tolerance indices including stress susceptibility index، tolerance index، stress tolerance index (STI)، mean productivity (MP) and geometric mean productivity (GMP) were estimated. Analysis of variance for each maturity group showed that there was a significant genetic variation among the accessions for all of the mentioned criteria. Correlation analysis showed significant positive correlation coefficient between STI، MP، GMP and yield under both dry land and irrigated conditions، suggesting that the indices are more efficient in determining drought tolerant accessions. Over all، Eghlid، Asadabad and Bardeh accessions، with average yield of 6323، 5560 and 5666 kg ha-1 respectively، were introduced as suitable accessions for dry farming cultivation in dry land and irrigated farming systems. Classification of the accessions was performed using cluster analysis based on the three indices of STI، MP and GMP.