In vitro germination and pollen conservation of sorne Musa species

The yield ofbanana and plantain which is an important food is affected especially by black leaf streak disease. Pollen from resistant wild types is used by conventional breeding to create new hybrids resistant to black leaf streak disease. A strategy of pollen genetic resource preservation and storage is necessary for this breeding. The main objective of this study was to optimize the conditions for in vitro germination, conservation and storage of pollen from three ban ana diploids (Musa acuminata). Pollen grains used in this study were collected from Njombe and Ekona banana collections. The basal media used for in vitro culture were th ose of Heslop-Harrison and Brewbaker and Kwack. Different temperature and pH values tested allowed for the evaluation of germination rates. Pollen were desiccated and stored in a freezer ( -20°C) and in a refrigera tor ( + 10°C). The results obtained showed that the basal medium of Heslop-Harrison supplemented with 5% sucrose allowed to obtain optimum pollen germination rate. The optimum temperature was 30°C and the optimum pH values were 6.5 for Calcutta and 6.8 for M53 and Zebrina. The pollen grains of the three varieties can be conserved freshly in the refrigerator at+ 10°C for at !east two months. These results are very important for ban ana and plantain breeding programs because the conditions of pollen storage for the three varieties are weil established and permit genetic material sharing and diffusion between different ban ana research centers. (Résumé d'auteur