Inheritance of in vitro Digestibility in Smooth Bromegrass1

The potentially useful variability for selection towards greater digestibility within a breeding nursery of smooth bromegrass (Bromus inermis Leyss.) was investigated by estimating the additive genetic effects for in vitro digestibility in a 6‐clone diallel cross. General combining ability was found to be a highly significant source of variation in determinations made on both the 1965 and 1967 harvests. An estimate of heritability obtained by doubling the regression of array means on the corresponding parental means was high, h2 = 1.06. Though correlations between such agronomic characters as height and seed set with in vitro digestibility were negative, they were low enough to make possible the selection of a more digestible synthetic variety with desirable agronomic characteristics.