The in vitro digestibility of parents and hybrids of cocksfoot (Dactylis glomerata L.)

Abstract

The digestibility of a range of genotypes of cocksfoot (Dactylis glomerata L.) and their hybrids was estimated by an in vitro technique at eight harvests over a period of 14 months. The material for analysis was grown in a Mediterranean type environment with summer irrigation and obtained by recurrent defoliation of sward plots.

Digestibility values tended to be lower in summer than in winter, although some material showed a fall in digestibility in the middle of winter.

Within a harvest there were correlations between general combining ability and parental performance, but there was little uniformity in ranking of parents or their progenies from one harvest to the next, which would make selection for uniform high digestibility very difficult. Reasons for the fluctuations are not known, and were not obviously correlated with any aspect of the growth rhythm apart from a correlation with heading on one harvest occasion.