Fecundity Effects of Dichogamy in an Asynchronically Flowering Population: a Genetic Model

Timing of pollen presentation and ovule maturation at the levelof the flower, individual and population may exert a profoundinfluence on individual fitness and population structure. Weexplored the evolutionary consequences of asynchrony in floweringin a population of dichogamous plants, making use of a geneticmodel to represent pollen and ovule availability over time.When the model was run for 18 generations, starting from a mixedpopulation of both early- and late flowering, protandric andprotoginous genotypes, the system evolved differently accordingto whether genetic dominance for precocity (or lateness) waspresent or absent. Under the assumption of dominance, the populationevolved towards a structure dominated by protandrous, late floweringgenotypes. In the absence of dominance, the system seemed toattain steady state equilibrium in which both dichogamous modescoexisted in predominantly intermediate-flowering genotypes.Copyright1998 Annals of Botany Company Dichogamy, protandry, protogyny, asynchronic flowering, genetic model.