COMPARISON OF THE PERFORMANCE OF SUBTERRANEAN CLOVER CULTIVARS IN SOUTHERN NEW-SOUTH-WALES .1. PERSISTENCE, PRODUCTIVITY, AND SEED YIELDS

The density, productivity, flowering characteristics, and seed reserve s of 14 lines (10 cultivars and 4 experimental lines) of subterranean clover were observed over 5 years (1983-87) on a red earth soil at Wag ga Wagga, New South Wales. Plant density increased from 149-318 plants /m2:in 1983 to 1975-13925 plants/m2 in 1987. Herbage yields of all cul tivars during autumn-winter were similar in most years except in July 1985 when Seaton Park was superior. Cultivars in the midseason or late r flowering groups were more productive in late spring and better able to utilise the extended growing seasons that occur periodically in th is environment. The mean time from emergence to 5% flowering of all cu ltivars was 168 days with March germination in 1985 but decreased to 1 35 days with May germination in 1986. The number of days to flowering at Wagga Wagga was highly correlated with maturity ranking at Perth (r 2 = 0.92 in 1985 and r2 = 0.93 in 1986). In the first year, average se ed set was 295 kg seed/ha, but by summer of the fourth year the seed p ool ranged from 124 kg/ha for Clare to 1190 kg/ha for Nungarin, the ea rliest flowering cultivar. The quantity of hard seed that carried over to the next year varied significantly between cultivars, with Enfield , Woogenellup, and Clare having the least, and Nungarin, Northam, Dalk eith, and Daliak the most. Seed set was related to maturity ranking on ly in 1984, although root disease probably affected seed yields in 198 5-86. The proportion of hard seed that carried over was much higher th an expected, particularly in soft-seeded cultivars. The newly released cultivar Junee was well adapted to the environment; it was later matu ring than the recommended cultivar Seaton Park but was able to maintai n high seed reserves. Karridale, another new cultivar, maintained high er seed reserves than the older Mount Barker.