Genetic Variation and Interrelationships of In Vitro Dry Matter Disappearance and Fiber Content in Orchardgrass Herbage1

Forage digestibility, fiber content, and their relationship to animal performance are important aspects of improving forage quality through plant breeding. The objectives of this study were to determine the genetic variation and heritability of in vitro dry matter disappearance(IVDMD), acid detergent fiber (ADF), neutral tergent fiber (NDF), and to examine the interrelationships among these quality factors in orchardgrass (Dactylis glomerata L.) herbage. Fourteen selected orchardgrass parents and their open‐pollinated progenies were transplanted and planted, respectively, into a randomized, complete block experiment at Mt. Vernon, Mo. The forage was analyzed for IVDMD, ADF, and NDF at each of three harvest dates in 1976 and 1977. Parents differed significantly for all of these quality traits. There was less variation among the progenies. Years and harvests within years were significantly different. Narrow‐sense heritabilities ranged from 49 to 91, 21 to 126, and 0 to 110% for IVDMD, ADF, and NDF respectively, suggesting improvement of these traits in the populations studied may be possible through breeding Correlations of IVDMD, ADF, and NDF with yield were low at the first harvest, but significant in the re‐growth. Maturity was negatively associated with these quality factors at the first harvest date. Stability for these traits between years was favorable