VARIABILITY FOR IN VITRO DIGESTIBILITY OF CRESTED WHEATGRASS
Significant differences in in vitro digestible organic matter (IVDOM) were found between plants of diploid Agropyron cristatum (L.) Gaertn. and tetraploid A. desertorum (Fisch.) Schult. Narrow-sense heritabilities for IVDOM ranged from 0.36 to 0.76. IVDOM showed no relationship to plant height, forage yield and lodging percentage, but was significantly correlated with leaf percentage. Diploid strains were more palatable than tetraploids and were significantly superior in IVDOM. A sharp decline in in vitro digestible dry matter (IVDDM) occurred from heading to the end of anthesis with little decline thereafter. Approximately 1 wk prior to anthesis, the IVDDM of crested wheatgrass was similar to that of bromegrass (Bromus inermis Leyss.), but at subsequent stages crested wheatgrass was inferior. It was concluded that limited progress in breeding for quality in crested wheatgrass was possible using in vitro testing.