Abstract:Pollen fertility, seed-set and incidence of apomictic and sexual embryo sacs in Apluda mutica under different photoperiods were investigated. There were no differences in pollen fertility between treated and untreated plants. No difference in the rate of seed-setting was found between decreasing photoperiods and natural photoperiod. Flowering and seed-setting were retarded greatly as photoperiod was greater than natural photoperiod during inflorescence development. Frequency of apomixis was from 0.41 to 0.64 when the plant was exposed to natural photoperiod, and to that with addition of one hour. The frequency of apomixis reduced to 0.19-0.22 if natural photoperiod was decreased by 1 or 2 hours, or increased by 2 hours, showing that the frequency of apomixis was greatly reduced as compared to the control or to the condition of natural photoperiod with one hour increase.