Drought resistance evaluation based on forage yield in accessions of Agropyron trichophorum by drought resistance indices

Drought resistance of 24 accessions of Agropyron trichophorum was examined based on forage yield in a complete block design with three replications under normal and dry land farming system. Drought resistance indices of genotypes were measured for forage dry matter yield of two environment conditions including sensitivity to stress index (SSI), tolerance (TOL), mean productivity (MP), drought tolerant index (DTI), mean harmonic (MH) and geometrical mean of productivity (GMP). According to the results of variance analysis of drought resistance indices, significant variation was observed among accessions. Results of mean comparisons showed that genotypes 10 (Semirom), 23 (Mazandaran), 24 (Gorgan), 5 (Chaharmahal), 17 (Yasuj) and 9 (Eghlid) had higher values for forage dry matter yield in both environment conditions. With regard to the drought resistance indices, genotypes 10 (Semirom), 23 (Mazandaran) and 24 (Gorgan), showed the most resistance to drought stress. Obtained results were confirmed by results of cluster analysis and principle component analysis.