Eficiência do sistema reprodutivo de bananeira

Abstract

The genetic breeding of banana through hybridization is limited by the occurrence of sterility in most cultivars, resulting in low production or absence of seeds. There are few studies about sterility in banana which have been difficult the understanding of the involved processes and the probable strategies to overcome this barrier. The aim of this study was to elucidate the different aspects in the reproductive system of banana in order to contribute with the banana breeding program. The results showed the effect of collection time on the pollen viability of different diploid banana (Musa acuminata, AA), some aspects of in vivo fertilization and the influence of floral extracts on the pollen germination. The best result was obtained at time to anthesis, at 8 a.m. when the highest pollen germination and 8 a.m., highest pollen viability was observed. Pollinations were made daily in diploids (AA) and triploids (AAA and AAB) comparing the development of fertilized ovules. It was observed that the ovules from diploids plants increased in size gradually, starting seed formation process. On the other hand, in triploid AAA occurs the abortion of unfertilized ovules and consequent reduction in its size. In triploid AAB some ovules are fertilized, but their size is smaller compared to diploids. The performance of pollen differed in relation to different concentrations of the extracts of stigma and distal portion of the ovary added to the culture medium, both for in vitro germination and growth of the pollen tube.