IN-VITRO PLANT-REGENERATION FROM EMBRYOGENIC CULTURES OF A DIPLOID AND A TRIPLOID, CAVENDISH BANANA

Plant regeneration by somatic embryogenesis was attempted with diploid (Musa acuminata ssp. malaccensis) and triploid ('Grand Nain') bananas . Explants inoculated in vitro were, respectively, immature zygotic em bryos and male flower bud primordia. An histological study showed that the embryogenic process involves a sequence of similar events for bot h species. A yellow-green compact callus was initiated, which consiste d of an actively dividing meristematic zone surrounded by several laye rs of starchy cells. A white and friable callus, characterized by the presence of proembryonic cells, bicellular proembryos and proembryonal masses in its periphery gradually appeared, which finally gave rise t o somatic embryos from which plants were recovered. Induction media co ntained 2,4-D (and also NAA and IAA for the triploid); zeatin and kine tin were necessary for embryo maturation and 6-BA and IAA were used fo r germination.