Seed and hay production in 31 genotypes of desert wheatgrass (Agropyron desertorum) using drought tolerance indices

Desert wheatgrass, Agropyron desertorum (Fisch. ex Link) Schult, is one of important perennial grass species that naturally grows in Zagrous and Alborz mountains rangelands in the west and north of Iran. In order to identification of superior genotypes for both seed and dry matter (DM) yield, 31 genotypes were sown in two separate experiments under optimum and drought stress condition using randomized complete block designs with three replications in Arak, Iran, during 2004-2006. Seeds and DM yield in optimum (Yp) and stress (Ys) condition for each genotypes were used to estimate the five drought resistance indices as: tolerance index (TOL), stress susceptibility index (SSI), mean productivity (MP), geometric mean productivity (GMP) and stress tolerance index (STI). The data subsequently used in principal components analysis. Based on bi-plot of the first two principal component scores, genotypes were distributed into four groups. For seed yield 631P5, 747M, 747P11 and 213P11 with average values 430 to 503 kg/h and for DM yield, 3477PM, 3477PM, 3965P11 and 341P11 with average values 2060 to 2260 Kg/h were recognized as the best varieties for dry condition. The 742P5, 1369P6, 3477P4, 287P8 and 341M for seed yield and 3477M, 3965P15, 631P2, 4036M and 341P11 for DM yield were introduced as the best genotypes for cultivation in semi arid regions. In simultaneous selection for both seed and DM yield, 631P5 (Ghazvin), 747M (Ghazvin), 341M were introduced for arid regions and 3477P4, 341P11, 287P8 (Hamadan), 1369P6 (Hamadan) and 3477M for semi arid regions of central province of Iran.