عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In order to determine the effects of phenological stages and the best harvesting time for yield and quality traits in Elymus hispidus (var. hispidus var. podperae var.villosus), an experiment was conducted in Cisab Research Station, Northern Khorasan, Iran during 2005-2006. The seeds of varieties were sown in a randomized completely block design (RCBD) with three replications under dryland farming system. Forage yield was cut at six phenological stages including vegetative, stemmy, ear emergence, milky, soft dough seeds and maturity. Dry matter (DM) yield and five quality traits including Dry Matter Digestibility (DMD), Water Soluble Carbohydrates (WSC), Crude Protein (CP), Acid Detergent Fiber (ADF) and total Ash were estimated using Near Infra-Red spectroscopy (NIRS). Data were analyzed using a split-plot in time design. Results showed significant differences for all traits among the phenological stages. DMD, CP, and ash were highest when the plants were immature and tend to drop sharply as the plants go to soft dough stage. In contrast, the average values of ADF and DM yield increased from vegetative to soft dough stage. WSC values were inconsistent over different phenological stages. Var. villosus with average values of 50.3, 16.3, and 10.1 percent for DMD, CP, and WSC, respectively had higher quality as compared with other two varieties. Var. hispidus with average values of 1433 Kg/ha DM yield had higher production as compared with two other varieties. However, its quality was low. The results showed that the highest digestible yield and protein yield were obtained in ear emergence stage for varieties. The results of correlation analysis showed positive and significant relationship between DMD and both CP and ASH. Whereas, ADF and same traits was negatively correlated. The correlation between DM yield and WSC with both DMD and CF was low and inconsistent over six phenological stages.