Abstract
Segmantal analyses of all the 16 types of X-ray induced reciprocal translocations in T. aegilopoides (aT1-aT7) and T. monococcum (mT1-mT9)have been completed as given in Tab. IV, in which the frequency of reciprocol translocations of each of the seven chromosomes are also summed up.
In the hybrid, mT1×aT4=f-eg/fe-g, two types of gametes, (f-e) and (e-g), are expected to be functional. In fact, when the stigmas of the hybrid were pollinated with normal pollen grains, the frequency of the fertilized female gametes, (f-e) and (e-g), amounted to 56.52% and 43.48%, respectively. However, when the stigmas of the normal plants were pollinated with the pollen grains of the hybrid, that of the functional male gametes, (f-e) and (e-g), amounted to 89.01%/ and 10.99%, respectively. These results indicate the competition between (f-e) and (e-g) pollen grains in the rapidity of growth.
RT-method was applied for linkage studies of the X-ray induced mutations as well as spontaneous characters, and 7 linkage groups have been established (Tab. VIII). 4 cases of the recurrence of identical mutations were recorded as given in Tab. V.
In an attempt to combine the chromosomes into larger rings, successive crosses among the established RT-types have been made. Consequently all possible combinations of rings and pairs from the 14 Einkorn chromosomes have been realized, giving a series of structural hybrids comparable with the well known situation in Oenothera. Fertilities of thus synthesized individuals having those chromosome constitutions are discussed in regard to the meiotic behavior of ring complexes.
Permanent structural hybrids are expected to be synthesized from the cross-combinations involving lethals, one associating with d- and another with f-chromosome, as given in Tab. IX.
