PRODUCTIVITY UNDER CONTRASTING CUTTING REGIMES OF PERENNIAL RYEGRASS SELECTED FOR SHORT AND LONG LEAVES

The productivity of short-leaved and long-leaved perennial ryegrass wa s evaluated in 5 different sites. In each site, half-sib families, der ived from the first cycle of divergent selection on leaf length, were managed both under infrequent cutting and under frequent cutting simul ating grazing. Despite the importance of the effects of the site and t he cutting frequency, the dry matter yield was dependent on the intera ction between the morphogenetic type resulting from the selection and the cutting frequency imposed by the management. Thus, under infrequen t cutting, the long-leaved families on average out-yielded the short-l eaved families. Conversely, under frequent cutting the short-leaved fa milies were on average the most productive. The use of morphogenetic t raits as selection criteria in breeding for management-dependent yield is briefly discussed.