Effect of“Stylar Pollination”on in vitro Seed Setting of Petunia hybrida

Abstract

The present investigation deals with the effect of pollination on formation of mature seeds on excised placenta cultivated in vitro.
Artificial pollination was performed by the two following methods: (i) pollen grains were dusted directly onto the ovules with a placenta (placental pollination); (ii) styles were excised aseptically, cut into about 7 to 10mm in length after applying pollen grains onto the stigma, and then were inoculated on or around ovules with a placenta (stylar pollination).
Placental pollination. In self- and cross-pollination of the clone W166H, 3.1 and 2.9 mature seeds per ovary were obtained, respectively. The mature seeds which were detached from the placenta were sown on a fresh medium containing agar alone, and then some of them germinated.
Germinating pollen grains were observed on both self- and cross-pollination explants of the clone K146BH, but neither of the combinations produced mature seeds.
Stylar pollination. A number of mature seeds were obtained by self-and cross-pollination of clone W166H, that is, 12.2 seeds per ovary in self-pollination and 11.5 seeds in cross-pollination, respectively, were obtained. About one-fourth of these seeds germinated.
In self- and cross-pollination of clone K146BH, 5.2 and 5.9 mature seeds per ovary were obtained, respectively. Some of these seeds which detached from the placenta were germinated normally on a fresh medium containing agar only.
It was concluded that the number of mature seeds per ovary depends upon the technique of pollination, that is, stylar pollination was substantially more successful than the placental pollination.