Manifold effects of the cyanogenic loci in white clover

Abstract

In white clover alternate alleles Ac/ac and Li/Ii at two unlinked loci determine the presence/absence of cyanogenic glucosides and the enzyme linamarase respectively. Plants possessing both cyanogenic glucosides and enzyme are cyanogenic. Morphological measurements were made on a random sample of plants from a population polymorphic at both loci. Individuals possessing linamarase had larger leaves than those lacking the enzyme. Competition experiments between all phenotypes showed a significant effect of Li phenotype frequency on total yield. Competitive interactions were such as to maintain polymorphism at the Li locus. It is concluded that the pattern of variation at the Ac and Li loci cannot be adequately explained by selection which discriminates between cyanogenic and acyanogenic phenotypes. © 1981 The Genetical Society of Great Britain.