Effect of Defloration and Restriction of the Number of Flower Clusters on the Progression of Successive Flowering and Seed-setting in Common Buckwheat (Fagopyrum esculentum Moench).

Abstract

This study was conducted to know the relationship among vegetative growth, progression of successive flowering, the number of flowers and flowering period, and seed-setting in common buckwheat. 1) All flowers were removed immediately after flowering in order to prevent seed-setting in Shinanonatsusoba. (summer ecotype) in summer. The number of flowers and flower clusters were increased and the flowering period was prolonged by this treatment, although the progression rate of successive flowering was little affected. The number of flowers per flower cluster was slightly increased by the treatment although not significantly. Increased flowers and flower clusters of the treated plants were produced on the higher order branches which developed during the later period. 2) All the other flower clusters except one were removed by top pinching and disbudding in Miyazakizairai (autumn ecotype) cultivated in summer, which had a low seed-setting ratio, to induce nutrient rich condition for the remained flower cluster. Seed-setting ratio was increased from 3% to 10%, although the progression rate of successive flowering and the number of flowering were little affected. These results show that the growth of stem and leaves affects the seed-setting ratio and the seed-setting affects the growth of high order lateral branches and the duration of successive flowering through the distribution of nutrients. The progression rate of successive flowering seems to be influenced by some other physiological mechanisms.