Productivity under contrasting cutting regimes of perennial ryegrass selected for short and long leaves

The productivity of short-leaved and long-leaved perennial ryegrass was evaluated in 5 different sites. In each site, half-sib families, derived from the first cycle of divergent selection on leaf length, were managed both under infrequent cutting and under frequent cutting simulating grazing. Despite the importance of the effects of the site and the cutting frequency, the dry matter yield was dependent on the interaction between the morphogenetic type resulting from the selection and the cutting frequency imposed by the management. Thus, under infrequent cutting, the long-leaved families on average out-yielded the short-leaved families. Conversely, under frequent cutting the short-leaved families were on average the most productive. The use of morphogenetic traits as selection criteria in breeding for management-dependent yield is briefly discussed.