Some Considerations on the Evolutionary Dynamics of Cultivated Rice

Abstract

A re-view of previous theoretical studies on partly self-pollinated plant populations and a report of the authors'' studies dealing with the effects of seed dormancy and vegetative propagation on population structure, and with the change in frequency of a gene controlling selfing probability. It was pointed out that the breeding system of the perennis type of wild rice, having seeds dormant for a long period, which is partly cross-pollinated and capable of propagating vegetatively, would be quite suitable for accumulating genetic variation in its populations. It was also suggested that selfing genes can increase by themselves unless counteracted by another force favoring heterozygotes. Therefore, if the habitat is controlled by man to assume conditions of cultivated fields and homozygous plants become relatively advantageous, the populations will tend toward selfing.