IMPROVEMENT OF CAVENDISH BANANA CULTIVARS THROUGH CONVENTIONAL BREEDING

In their article “Banana breeding: polyploidy, disease resistance and productivity”, Stover and Buddenhagen (1986) reported the results of the evaluation of female fertility in Cavendish banana cultivars. They showed that the pollination of a few hundred bunches of ‘Valery’ (AAA) and other Cavendish clones with pollen from diploids did not yield seed. The authors concluded that “the apparent seed sterility of Cavendish cultivars (without any research to determine or overcome the blocks) precluded their use as female parents in conventional breeding programs”. The scientific community accepted these observations as fact and did not carry out additional tests, because the commercial cultivars of banana for export are all triploid and parthenocarpic. The triploid condition of the Cavendish banana causes them to produce many sterile eggs, and the process of parthenocarpy allows the development of fruit without ovule fertilization. On the assumption that Cavendish cultivars have low fertility, the Banana and Plantain Breeding Program at the Honduran Foundation for Agricultural Research (FHIA), starting in 2002, pollinated 20,000 bunches, approximately 2 million fingers, of the Cavendish cultivars ‘Grand Naine’ and ‘Williams’ with pollen from 10 Cavendish cultivars for the development of Cavendish tetraploids. As a result, 200 seeds with 40 viable embryos were obtained, from which 20 tetraploid hybrids were developed. These results confirmed the assumption that Cavendish cultivars have low fertility, which allows their use in conventional breeding methods to create new progenies. The selected tetraploid progenies were crossed with improved FHIA diploids for the development of second generation triploid hybrids. As a result of this cross, two hybrids with resistance to black leaf streak and Fusarium wilt race 1, have been pre-selected. These hybrids exhibit similar performance to known Cavendish cultivars.