Pod Drop Research Articles

Ecological Studies of Fruiting Behaviours of Azuki Beans : Phaseolus angularis W. F. Wight

Experiments were conducted on fruiting behaviours of Azuki beans, and although final conclusions could not be made with regards to all the varieties, the following points were observed in the variety Wase-maruba which is commonly cultivated in Hokkaido. 1) Blossoming commences usually from the 1st node of the 5th and the 7th branches, and succeeds upwards until the last node is reached, whereas in the 3rd branch blossoming starts from the 2nd or 3rd node and in the 4th branch from the 2nd node. In every inflorescence the blossoming almost invariably commences from the basal flower, whereas the ones which appear in its lower sites are actually the growth of adventitious buds. 2) Blossoming period ranges for over a month, but mainly is for 3-4 weeks. 3) The blossoming curve for the 1st week from the initial blossoming is comparatively low, in the slope and is followed by a rapid rise with a peak continuing for 2 weeks upon which the curve gradually descends. 4) Fluctuations in the number of dropping flowers and pods during flowering are as follows : whereas the number is almost negligible until the 1st half of the blossoming peak, the number gradually increases and after the 2nd half on a sudden rise in numbers is seen. The pod dropping continues even after the termination of blossoming, but the majority drop within 1 week. from the beginning of flowering. 5) In regards to flower and pod dropping with reference to stem-node order, the rate is the lowest in the 6th, 7th and 8th middle nodes and is medium in te 5th, 4th and 3rd basal nodes and also in the 9th, 10th and 11th tip nodes. In the nodes upper than the 12th the rate rises rapidly. Thus it may be said that the pod-setting on main stem is influenced remarkably by the site on it. 6) In the majority of flowers it was observed that the embryo-sac formation as well as the fertilization were, almost completely functioned, and therefore the causality for above-mentioned flower-and pod-dropping should not be failures in those functions.

Studies on the reproductive physiology of common beans, Phaseolus vulgaris L. IV. Some relations among the flower bud differentiation, flowering and fruiting in common beans

1. In the tall variety, Kentucky Wonder, the number of flowers was only about 20_??_30% of the number of flower buds which had differentiated by the 45th day from seed-sowing date. Percentae of pod setting against the number of flowers was about 20_??_35%. So the set percentage of pods against the number of flower buds was very low, i. e. only 4.5_??_10.8%. 2. The causes of this sparseness of set are dis-cussed in this paper, comparing other leguminous vegetables. Competition in nutrition and high tem-peratures seem to be the two important causes. Competition in nutrition among flower buds of whole plant and of the same inflorescence and competition between the flower bud differentiation and vegetative growth will cause the many flower and pod drop-ping. 3. Many effective flower buds were distributed densely near the tenth node in the tall variety. 4. As the seed-sowing date was delayed, the percentages of pod setting against both the number of flower buds and the number of opened flowers were lowered. 5. The mode of anthesis time lied between 5_??_7 am. Few flowers opened at abont 2 am. already. The anthesis of flowers was observed till 10 am.

Physiological Studies on Blooming and Podding in Soy Bean Plant (Preliminary Report) : (1) Experimental Studies on Flower Dropping and Pod Shedding

1. Observations were made on blooming and dropping of flowers and young pods of soy bean plants. 2. Rate of planting, soil moisture, and thinning young buds seeded to have no marked effects on dropping of flowers and pods, so far as the present experiment showed. 3. Soy bean plants cultivated in foot path of paddy fields (Azemame) showed smaller rate or flower and the pod dropping as compared with those grown on upland fields by usual practice. The cause for the difference in dropping may be atributed to the difference in the microclimatic environment. 4. A pronounced decrease in dropping rate was observed in plots under short day. The decrease, however, does not seem to be due to photoperiodism alone; it seemed highly probable to be due to the complex of photoperiodism, temperature, and humidity factors, although further experiments should be necessary before conclusion.