Detection of selection in populations of white clover (Trifolium repens L.)

Seed populations of white clover polymorphic for the presence/absence of both ovariogenic glucosides and the hydrolysing enzyme linamarase, were introduced into three natural populations. Over the first six months of life a significant increase in the frequency of linamarase containing individuals occurred. Estimated selection coefficients against plants lacking linamarase were in the region of 0.3. This result may have been due to selection at the enzyme locus alone, or to selection favouring cyanogenic individuals which possess both cyanogenic glucosides and enzyme.