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Sub clovers for Tasmania: production of early mid season and late groups

P.M. Evans and J.A. Carpenter

Dept of Agriculture, Mt Pleasant Laboratories, Launceston Sth, Tasmania

Rainfall and evaporation patters and latitude make late flowering cultivars of sub clover (Trifolium subterraneum) the obvious choice for the Tasmanian environment. However, same early-mid-season lines seem to have the ability to continue growing actively after flowering starts if the season is favourable (1). Introductions and crossbreds from the National Sub Clover Improvement Program (NSCIP) are being evaluated. Data from the best five mid-season-late lines of sub-species subterraneum and early-mid-season yanninicum lines, together with four commercial cultivars used as controls, are presented here.


Cultural practices and fertiliser applications used were those recommended for tie districts. All sites were drilled with perennial ryegrass cv. Nui at 6 kg ha-1. Two replicates of plots of 2mix 0.5m of 124 NSCIP lines and registered cultivars were sown by hand at 30 kg ha-1 after inoculation, in May 1985 at all sites. The Epping site was on a virgin, sandy lateritic soil. The Relbia site was on a fertile alluvial clay; the Whitemore site was in a cold district on a solodised solonetz clay loam. Seedling numbers were counted each autumn and dry matter production was estimated with a pasture probe (2); trials were grazed after each sampling. Flowering tines wire recorded at 3-4 day intervals. Seed yield was determined by taking two 78.5 cm-1 soil cores to 4 cm depth per plot in early summer.

Results and Discussion

The mid-season-late subterraneum lines established well, but the yanninicum lines established poorly due to poor seed scarification. In 1985, the subterraneum lines had about 3 times more seedlings established and their dry matter production was more than double that of the yanninicum lines (Table 1). In 1986, seedling numbers increased 10 fold over 1985 for both subspecies at Epping and Relbia and the best five lines of both groups yielded about the same (Table 1). Seedling numbers only increased five-fold at Whitemore and at this site the subterraneum lines outyielded the yanninicun lines. Optimum seedling densities were possibly not reached at Whitemore by the latter group. There was a 29 day difference in flowering tine between the earliest crossbred 76Y51.26 and the latest introduction, GF.177.1, but 76Y51.26 produced slightly more dry matter across all three sites. The data suggest that sane early-mid-season yanninicum lines have the ability to keep growing when conditions are favourable and can regenerate well in the second season even if establishment after sowing is poor. The best mid-late lines show a potential to replace currently recommended cultivars in Tasmania, having better dry matter production and regeneration ability.

Table 1 Establishment year - 1985

1. Gladstones, J.S. 1985, W.A.D.A. ISSN 0157-6259

2. Vickery, P.J. and Nicol, G.R 1982 CSIRO. Anim. Res. Lab. T. Pap. No. 99 22p

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