Pollen success, functional gender and assortative mating in an experimental plant population

Abstract

Six uniquely genetically marked individuals were extracted from a natural population of the perennial, self-incompatible grass Cynosurus cristatus. Individuals were clonally replicated and used to construct an experimental population within which pollination and seed set were allowed to occur. The relative allocation to female reproduction, and the pollen contribution to progeny were measured for each clone. A model was developed to predict the expected pollen contribution of each clone on the assumption that clones showed a constant ratio of male/female reproductive resource allocation and equal pollen fitness. Highly significant differences were found between observed and expected pollen contributions of clones. Two clones showed significant deviations from equisexual reproduction. Differences in flowering time among clones led to assortative mating between clones which flowered synchronously, and this was accompanied by changes in the genotypic composition of the pollen pool through the flowering season. © 1987 The Genetical Society of Great Britain.