Perennial ryegrass cultivars: herbage yield in multi-site plot trials

Abstract

Perennial ryegrass (Lolium perenne) cultivars adapted to New Zealand conditions are bred by several scientifically equipped New Zealand interests. New cultivars are evaluated in a network of trials organised by the New Zealand Plant Breeding and Research Association. This paper presents data from 17 trials completed throughout New Zealand since 1991. Data were analysed for each trial and then in a multi-site analysis enabling comparison of estimated cultivar means, over all New Zealand trials, North Island trials and Canterbury trials. New cultivars released to the market yielded on average 6% more herbage annually, and 9% in summer, than cultivars available before 1991. Other cultivars were evaluated but showed no yield advantage and have not been commercially released. Point analysis of plots in the final season of trials indicated that recently released cultivars maintain ground cover at least as well as the older ones. Limited data for rust infection indicated that the oldest cultivars are the most severely affected. Keywords: cultivar evaluation, endophyte, NZPBRA, pasture plant breeding, perennial ryegrass