一寸蚕豆の結果習性に関する研究(第1報)

播種期によるその差異について

抄録

In order to study the fruiting habit of “Issun” broad bean (a large seeded variety), the seeds were sown on the following dates: September 25, October 5, 15, 25 and November 4, in Awa Branch, Chiba Agricultural Experiment Station.
The plants planted earlier in the fall made pretty good growth byfore the hard winter season, and even in winter the bean plants continued their development. In the latter part of March, they started to make rapid growth, then stopped their growth at about the end of April, when maximum temperature exceeded 20°C, in all plots irrespec-tive to the dates of their planting. Consequently, the amount of growth was larger in the plants planted earlier than planted later in the fall.
The branching of stems was made according to a definite order. The number of stems per plant increased rapidly in the early part of May, and thereafter decreased by the death of the stems.
Only 58_??_67 percent of the floower-buds bloomed, and the remainder of the buds aborted before blooming. The earlier the date of the first blooming, the earlier the date of planting was. The number of flowers increased as the temperature went up in the spring, reached its peak, then dropped down uddenly at the middle of April, when maximum temperature exceeded 20°C. Three or four flowering cycles were observed in the planted earlier, while less cycles were observed in ones planted later.
5_??_9 percent of the flowers developed into pods. As the plants planted earlier bore larger number of flowers, they produced more harvested pods.
The greater part of pods developed from the first or second flowers in the cluster, and the rates of harvested pods to the flowers in the third: or higher flowers in the cluster were only 1_??_6 percent.
The fruiting cycles could not be found in rela-tion to the flowering time, but was found in indi-vidual stems, in which they occured in every four or five nodes, though there were some differences according to the dates of plantings of the plants.
Large pods were obtained from the flowers, which had opened between the latter part of Feb-ruary and the early part of March. The size of pods became smaller as the time of blooming was earlier or later than the above mentioned period.
The time required from flowering to harvesting was 43_??_78 days, 53 days in average, and the earlier the date of blooming, the more the time required. About 790°C degreedays of heat summation were required from blooming to harvesting of pods.