Abstract
The objective of the present investigation was to examine the usefulness of ovule culture for the production of interspecific or intergeneric hybrids which failed in their growth during the development of crossed ovules. The experiments were carried out in the combination of Nicotiana tabacum and N. rustica. In this combination, many attempts to obtain the hybrids had previously been made. The reports showed that the pollen tubes of N. rustica stoped in the styles of N. tabacum and could not enter the ovules, while in the reciprocal cross, almost all of the crossed ovules failed in their development although fertilization took place and only a few hybrids could be obtained. The histological observation of the ovules of N. rustica pollinated by N. tabacum showed that the nucellar hyperplasy in the crossed ovules began 4 days or so after pollination and then almost all of the ovules shrinked and died from about 6 days after pollination(Fig.1). In the 5th day after pollination, the viable embryos at the stage of early globular were observed in the crossed ovules. This observation suggests that the crossed ovules should be excised and transferred to culture medium by the 5th day after pollination.
