Time distribution of seedlings emergence from single seed crops of several annual pasture legumes

Abstract

Seedling emergence from single seed crops of Dwalganup and Geraldton subterranean clover, Yamina cupped clover, Troodos and Kondinin rose clover, and Cyprus barrel medic, was studied in a low rainfall wheatbelt environment in Western Australia. The proportion of the original seed set recovered as seedlings was highest from the subterranean clovers in the first year but about the same for all genotypes in the second year. Few subterranean clover seeds were recovered in the third regeneration year either as seedlings or residual hard seeds, whereas significant proportions of the original seed of the other genotypes were obtained. More than 10 per cent of the original seed of Cyprus barrel medic and Yamina cupped clover remained ungerminated at the end of the third season. Between about 35 and 75 per cent of the original seed set was not accounted for in the genotypes studied. The proportions of the total seedling numbers that emerged following summer and early autumn rains were generally highest from the subterranean clovers and least from the cupped clover and medic. It is suggested that these different patterns of emergence within years were the result of differences in embyro dormancy rather than different patterns of hard seed breakdown.