2012 Volume 81 Issue 1 Pages 27-34
Although Japanese mango is produced under a fairly unique cultivation system and fetches high prices at market, further growth of the mango industry in Japan requires the development of new cultivars. However, since individual mango flowers are quite small, no more than 1 cm in diameter, a large number of skilled workers is necessary for artificial pollination, thus making it difficult to obtain a sufficient number of progenies for breeding. We therefore evaluated a methodology whereby progenies were obtained by open pollination and their male parent was subsequently determined by DNA markers. Two mango cultivars (‘Irwin’ and ‘Beni-Keitt’) were arranged in a plastic house and honeybees were released as a pollen vector for open pollination. Harvested fruits were characterized and their seeds were sown in a bed. The male parent of the germinated seedlings was then identified by five simple sequence repeat (SSR) markers. As a result of SSR genotyping, the male parents of 185 of 239 ‘Irwin’ seedlings were revealed; 79 were obtained by self-pollination and 106 from out-crossing. For ‘Beni-Keitt’, the male parent of 14 of the 20 seedlings was determined with two self-pollinated and 12 out-crossed. Preferential out-crossing in ‘Irwin’ was revealed using the chi-square test, although the considerable number of self-pollinated fruit obtained shows that a sufficient number of fruit can be set in a single-planted orchard. The effect of the male parent on fruit characteristics was subsequently examined, revealing that in ‘Irwin’ the Brix value of self-pollinated fruits was significantly higher than that of cross-pollinated fruits. Certain color values were, however, lower in self-pollinated ‘Irwin’ fruits.
