抄録
1. In these experiments variety Shogoin was used as material. Fertility was directly determined by pollen behavior on stigmas instead of by seed counts. It seems that the direct test of pollen behavior is a more accurate method than seed-set test to determine the fertility of the plant.
2. Self-compatible plants were sporadically found in a few members of this prevailing self-incompatible variety. The results obtained in two pedigreed cultures showed that the self-compatibility of these plants is a character which is not hereditary. Perhaps it is a physiological pseudo-fertility.
3. The results of self- and cross-pollinations in 1942 were exceedingly complex. Ten plants examined were divided into eight classes on the basis of cross-relations. All plants belonging to eight, elasses were self-incompatible. In inter-class pollinations there were both cross-compatible and -incompatible combinations. Differences in the reciprocal rea-ctions between certain classes were also found (Diagram 1).
4. Self- and cross-pollinations in sister plants obtained by selfing a self-incompatible plant (No. 4) used in the previous year were attempted in 1943 as progeny test. These ten plants were divided into three classes (a, b and c). Classes a and b were cross-compatible in both directions, but all other combinations were fully incompatible (Diagram 2).
5. These results may well be explained if the following items are assumed:
(a) Both self- and cross-incompatibility are determined by two pairs of incompatible factors (S and I). S is assumed to be epistatic to I, but S hypostatic to II (S>I, S<II).
(b) The interactions in fertilization are determined by the sporophytic origin of pollen. A genetic explanation for the results was given in diagram 3 and 4.
This interpretation is analogous to RILEY'S hypothesis on Capsella, although differing somewhat in detail.
