Association of the cyanogenic loci in white clover

Abstract

The inheritance of cyanogenesis in Trifolium repens is governed by two unlinked genes, Ac/ac and Li/li which determine the presence/absence of cyanogenic glucosides and their hydrolysing enzyme linamarase respectively. Plants possessing dominant alleles at both loci release hydrogen cyanide when their leaves are damaged. Analysis of phenotype frequencies in ten natural populations showed a significant positive association in phenotypic state between these two loci within populations. Taking into account the results of a subsidiary study which showed no significant deviation from random mating in a natural population of T. repens, the most likely explanation for the observed association in phenotypic state is selection favouring the cyanogenic phenotype. © 1982, Cambridge University Press. All rights reserved.