Studies on the flowering and fruiting of the broad bean, Vicia faba L.

Abstract

The flowering and fruiting habits of broad beans were studied, using 6 varieties, i.e. Wase, Kyûryû, Sanuki, Bôshû, Issun and Nagasaya.1. Seasonal change of number of open flowers was similar to that of number of pods harvested in its pattern. But, the set percentages were higher in early part of the flowering period.2. The varietal differences in the number of flowers per plant and the set percentage were hardly recognized among the 6 varieties tested.The percentages of harvested pods to the number of flowers were about 20%, but they varied with sowing dates and other factors.3. The first flowers of lower inflorescences opened earlier than those of upper ones in the same branch.4. The first flower of the main stem generally opened first, and the first flowers of branches opened generally in due order with the order of emergence of those branches, although there were some exceptions. In most cases, the flowers of lateral branches of the second order opened much later than those of the first order lateral branches.5. The flowers open indeterminately in each inflorescence.6. The number of flowers per inflorescence varied with nodes of branches, being few in both upper and lower nodes and increasing toward the middle portion. Most branches had 2-flowered inflorescences in the lowest nodes which bore inflorescences. Some nodes in the tip of branch bore 1-flowered inflorescences.7. Set percentages of 1-flowered inflorescences were less than those of the first flowers of 3-flowered inflorescences or of 4-flowered ones. It probably depends on the fast that 1-flowered inflorescences appear in the tips of branches where the nutrition become poorer.8. In the case where more than 2 flowers set in one inflorescence, those flowers opened generally on the same day. But the frequency of the cases in which both 2 flowers of the same inflorescence set were rather low, and it hardly took place that 3 flowers of the same inflorescence set.9. Mostly only the pods which came from the first flowers of the inflorescences could be harvested. In some cases the second flowers set pods that could be harvested. But the upper flowers than the third in the inflorescence rarely set.10. Of the 2-flowered inflorescences, it was more common that the lower flower opened earlier than the upper flower by one day. The cases that both upper and lower flowers opened on the same day and that the lower one opened earlier by two days took place less often. The cases that the differences of opening of two flowers of the same inflorescence were more than three days were very few.In the inflorescences that bore more than three flowers, the differences of anthesis dates of the first and the second flowers were similar to the abovementioned cases of 2-flowered inflorescences.