The effect of defoliation on flower production in subterranean clover (T. subterraneum L.)

Abstract

Three experiments were done in an open-sided glasshouse during the normal winter growing season. In experiment 1, swards of the Dwalganup strain which were severely defoliated, either after flower initiation or at early flowering, had 17% more flowers per unit ground area than uncut controls. Swards which were defoliated at both stages had 28% more flowers than the controls. In experiment 2, with single plants of the Dwalganup strain, comparable defoliations greatly decreased flower numbers per plant. The opposing effects of defoliation on flower numbers of single plants and of swards are believed to reflect opposing effects of defoliation on the rate of leaf appearance and on branching. In experiment 3, with single plants of the Dwalganup and Yarloop strains, either the young or the mature leaves were repeatedly removed before flower initiation. This delayed the date of commencement of flowering by 15–19 days; but the node of first flowering was not affected by defoliation.