Characterisation of the Kangaroo Valley ecotype of perennial ryegrass (Lolium perenne)

Abstract

A breeding program commenced in 1992 to produce perennial ryegrass (Lolium perenne) cultivars based on the Kangaroo Valley perennial ryegrass (KVPR) ecotype with improved winter and late season growth, disease resistance, and persistence. Perennial ryegrass plants (9000) were collected from 45 sites within the Kangaroo Valley and Shoalhaven flood plain in August 1992. Using principal component analysis, site differences were greatest for N percentage, Mg and Na concentration, and A1 saturation. Collections were space planted along with standard cultivars (Banks, Ellett, Embassy, Grasslands Lincoln, and Vedette) at Berry, New South Wales (34¦48'S), and Timboon, Victoria (38'32'S), with 50 treatments and 10 replicates. Plants were visually scored for seasonal yield, rust incidence, greenness, leafiness, persistence, habit, and tiller density at both sites. At Berry, leaf angle, leaf width, and heading date were determined. Despite the differences in moisture, temperature, and growth indices between the 2 test sites, seasonal yield scores (mean of 100 plants) at Berry and Timboon were highly genetically correlated (r = 0.79-0.99). Standard cultivars were higher yielding with higher tiller density but with a greater rust incidence than collections (P < 0.01). Collections originating from the Shoalhaven flood plain were higher yielding with greater tiller density than plants from the Kangaroo Valley (P < 0.01), although differences were not as great as site of origin differences would suggest. Selections have been made for polycross half-sib formation, and half-sib evaluation will take place at a number of sites to determine the average general combining ability of parent selections for synthetic cultivar production.