Factors Influencing Pollen Longevity, Germination, and Tube Growth in vitro of Kiwifruit, Actinidia deliciosa, cv. Matua

Abstract

In vitro conditions for germination and pollen tube elongation of freshly collected and stored kiwifruit pollen were studied.
1. The optimum temperature for the germination of fresh pollen was 30°C; whereas that for tube elongation was 25°C.
2. The optimum sucrose concentrations in the medium ranged from 5 to 15% for pollen germination and tube elongation. Glucose and fructose were inferior to sucrose under the same conditions.
3. The optimum pH for pollen germination and tube growth was 4.0.
4. Additions of boric acid (2 to 1, 000ppm) to 1% agar medium, adjusted to pH 5.5, and containing 10% sucrose accelerated pollen tube growth.
5. Kiwifruit pollen remained viable two weeks when stored at 4°C with silica gel as a desiccant. Pollen preserved in hexane at 4°C retained a high germination capacity even after one year.