Abstract
The seed yield of the primary inflorescence increased by the pinching off of the lateral buds on the first flowering day and 7 days after the first flowering due to the increase in the number of fruits. As the number of fruits per inflorescence hardly changed by the pinching off of the lateral buds conducted 14 days after the first flowering and later, it was suggested that the number of fruits should be determined before the 14th day after the first flowering. In those cases, the number of fruiting dichasia per inflorescence hardly changed, but the number of fruits per dichasium increased. This increase was caused by the fructification of the higher order flowers which bloomed later. The fourth order flowers at most in a dichasium bloomed and fructified in this study using the cultivar Shanghai. The fructification of the high order flowers usually gave rise to a mixture of immature and mature fruits at harvest and it is likely that the quality of oil became poor. It appears that the number of fruiting dichasia per inflorescence was determined at the inflorescence-developing-stage before flowering and that it slightly changed in this study because fruit setting took place in the mixed dichasia of male and female flowers. The seed weight seemed to be determined during the 30 day period after the first flowering. The length and the thickness of the seeds appeared to be determined 7 days later than the number of fruits which was earlier than in the case of the seed weight. The seed width appeared to be determined at the same time as the seed weight. Further investigations on the seed volume and seed weight should be carried out in future.
