Studies on the so-called "Home" and "Foreign" crops of seeds of Tokinashi radish, a Japanese spring variety. : III. On the physiological mechanism of the fasciation, and its selective action upon the. degeneration of the variety.

Abstract

l, The fasciation on the bolting stalks is often fo.und late in spring in the seeds growing fields of radish such as the warm region of Kyushu, Ja pan . 2. All of slow bolting strain produced in Kyoto prefecture showed the fasciation, while the early bolting strain, the so-called Baka Tokinashi radish, produced in Oita prefecture did not show it at all, and sorne of the intermediate type in the bolting behaviors produced in Gifu prefec, ture slightly presented the fasciatio, n . 3 . Fasciation was seen abundantly among the radishes sown in October, but lot among the ones sown in later, and when the seeds were sown in next March which was near the limit of sowing time in spring, the fasciation was again found . 4, Although all the mother plants sown in Obtober were transplanted every month from December to March, none of them resulted in the fasciati, on. However the non-transplanted ones were fasciated . 5. Amo. ng the plants ever sown in October, the ones which slowly bolted fasciated, but the early bolted ones were normal . 6 . From the results stated above the occ. urrence of the fasciation seeins to have hereditarily a close relation with the slow bolting character, but from the physiojogical point of view it might be said that the conversion from. the vegetative growth to the reproductive growth being incomplete and whenever the balance of the two is lost, fasciation oQcurs. 7 . The fasciated plants yield less quantities of. seeds than those of the norrnal plants . In consequence, the sioiv bolting plants tend to produce less quantities of seeds than the early bolting ones, and in the next generation the ratio of the early bolting plants will be increased more than that of the siower bolting ones . Whenever the seeds of radish will be cropped in the Foreign region; especially in the warmef region, the natural selection of the slow bolting strain like thls may be duly ascribed to be one of the great causes of the degeneiation of radish .