2021 Volume 20 Issue 2 Pages 149-156
We investigated the pollen quantity and morphology of 24 Bouvardia cultivars/lines and their germinability on different media, and evaluated the relationships between these characteristics and male fertility. First, the effects of various culture media and environmental conditions on the in vitro pollen germination of two species (B. ternifolia and B. longiflora) were examined. The conditions of 10% sucrose, 25°C, and 4h culture under light were selected as suitable for the germination of Bouvardia pollen. Second, the pollen characteristics, namely quantity, size, percentage of good quality pollen, and germinability, of 24 Bouvardia cultivars/lines (two B. ternifolia lines, two B. longiflora lines/cultivars, four 4x and eleven 8x hybrid cultivars, and three 8x and two 16x polyploid lines) were evaluated. The relationships between these pollen characteristics and male fertility were then analyzed. There was a strong positive correlation of male fertility with both pollen germination and the pollen tube length. These results suggest that the germinability of pollen significantly influences male fertility. Additionally, since the linear correlation between the pollen tube length and male fertility was strong, we consider that the pollen tube length could be applied as an index for evaluating male fertility in Bouvardia.
