Study of water deficit tolerance components in 12 accessions of Agropyron cristatum L.

Abstract
The study was carried out in order to investigate the effects of water deficit on forage yield and agronomic traits on 12 accessions of the species. The treatments included 3 irrigation regimes, without stress, moderate stress and severe stress. At harvesting date, data were collected on survival rate, fertile tiller percent, flag leaf length, peduncle length, plant height, spike length, number of spikelet, spike yield and straw yield. Results showed that the drought stress had no significant effect on survival rate, flag leaf length, spike length and number of spikelet. Whereas, low and moderate drought stress showed significant differences on fertile tiller percent, peduncle length, plant height, spike length and yield without spike. For straw yield, moderate and sever drought had significant different effects. Comparison of the means of survival rates indicated that the accessions of Parvar with average values of 85% and Arasbaran and Semirom with 45% had the higher and lower survival rate, respectively. Regarding fertile tiller percent, Mianeh with average values of 50% showed the lowest value. Regarding spike yield, Semirom and Mianeh with average values of 39.6 and 7.9 kg/ha had the higher and lower spike yield, respectively. Parvar and Mianeh with average values of 67.1 and 21.9 kg/ha had the higher and lower straw yield, respectively.