Evaluation of annual pasture legumes in northern New South Wales. 1. Trifolium subterraneum cultivars and lines

Abstract

Two subterranean clover (Trifolium subterraneum var. subterraneum and T. subterraneum var. brachycalycinum) evaluation studies were sown in replicated plots. The first study (experiment 1) comprised 30 entries sown in 1993 and 1994 and the second (experiment 2) had 85 entries sown in 1998. Green herbage mass (kg DM/ha) was assessed until spring 2000 (experiment 1) or 2001 (experiment 2). Limited data were also collected in experiment 1 to estimate hardseededness, seed yield and seedling regeneration. For each experiment, green herbage mass was examined using cubic smoothing splines. Plots of initial and final values assisted with data interpretation, and predicted values at the end of each experiment were used to assess significant (P = 0.05) cultivar/line differences. CPI 89846B (York), Junee and Clare performed better (P < 0.05) than Woogenellup, Seaton Park, Rosedale, Nuba and Goulburn (experiment 1, previously cultivated site). For the native pasture site, CPI 89846B, Junee, Clare and Woogenellup were better (P < 0.05) than Goulburn, Nuba and Rosedale. In experiment 2, the three cultivars, Clare, Antas and Rosedale, had similar predicted green herbage mass in spring 2001. In experiment 1, CPI 28012 had the lowest predicted green herbage mass in spring 2000. This line also had low seedling establishment and seed yield in 1993 and low seedling regeneration in 1994, 1995 and 1997. Early maturing cultivars/lines generally performed poorly in experiment 1 and, of the other lines, CPI 70100 performed best. However, in experiment 2, crosses with this line as a parent had variable green herbage mass in spring 2001.