A TIME-SERIES ANALYSIS OF THE POPULATION-GENETICS OF THE SELF-INCOMPATIBILITY POLYMORPHISM .2. FREQUENCY-EQUIVALENT POPULATION AND THE NUMBER OF ALLELES THAT CAN BE MAINTAINED IN A POPULATION

The concept of a frequency-equivalent population is introduced, which is the panmictic population that has the same allele frequency distrib ution as a given population with overlapping generations and variation in plant size. It differs from the traditional concept of effective p opulation size, N-e, in that the effect of variation in plant size is to make the frequency-equivalent population larger than the actual pop ulation, whereas the effective population size is smaller. Overlapping generations has the opposite effect. The number of alleles that can b e maintained in a population at equilibrium is calculated incorporatin g these two factors, with variation in plant size significantly reduci ng the number of alleles and overlapping generations increasing the nu mber of alleles that can be maintained.