Induction of pseudo-fertility by means of repeated pollination in self-incompatible Petunia hybrida

Abstract

In this paper the results are presented on method of overcoming self-incompatibility in Petunia hybrida by means of repetition of self-pollinations.As for the materials Petunia hybrida, clone W 116 K, W 166H and K 146BH which belong to the gametophytic incompatibility system were used.1. None of those three clones have self-fertility at anthesis and the inter-clonal pollination showed perfect fertility, namely the complete self-incompatibility was confirmed.2. The pollen tubes in the compatible pollination have reached the ovary about 36 hours after pollination, while in the incompatible pollination the pollen tubes have ceased their growth at the style. The tips of the pollen tubes positioned at 67% of the total length of style 56% in W 166K, in W 166 H, 17% in K 146BH.3. In all three clones the pseudo-fertility by bud pollination was recognized, namely the self-fertility appeared on 6 days before anthesis, reaching its maximum on 5th day and disappeared completely 3 days before anthesis. The pseudo-fertility was the highest in W 166K, followed by W 166H and was the lowest in K 146BH.4. Three days before anthesis when the pseudo-fertility by bud pollination had disappeard completely, the self-pollination was carried out repeatedly with 24 hours interval, which resulted in the induction of the pseudo-fertility in the both clones W 166K and W 166H. The rate of fertilization and yield of seeds have increased as the frequency of pollination have increased. The method to induce the pseudo-fertility by repetition of the incompatible pollination was designated as“repeated pollination”.5. It was assumed from the results of the combination of incompatible and compatible pollination that the pollen tubes which have ceased their growth once in the style after the first pollination have not resumed the growth, but the pollination after the second time made pollen tubes grow, and they penetrated into the conducting tissue, thus taking part in the fertilization and seed formation.