Abstract
Genetical and physiological analyses were undertaken in interspecific incompatibility between Nicotiana alata and N. langsdorffii. Experiments were also done to elucidate the relationship between self-incompatibility and interspecific incompatibility.
There is bilateral interspecific incompatibility between N. alata and N. langsdorffii though the combinations with N. langsdorffii as female show higher compatibility than its reciprocal one. It is supposed that the gene which controls interspecific incompatibility is not a definite gene such as S in self-incompatibility, but is polygene. Though pseudo-self-compatibility in N. langsdorfjii is probably also controlled by polygene, plygenes participating in self- and interspecific-incompatibility are different each other. In both incompatibilities, the growth rate of incompatible pollen-tube is much slower than in compatible combination, and fertility increases by bud pollination. To understand these facts, hypotheses are proposed in the present paper.
