Somatic hybridization by electrofusion of banana protoplasts

Somatic hybridization between triploid and diploid bananas was attempted by using protoplast electrofusion and nurse culture techniques. Protoplasts from embryogenic cell suspensions of 'Maçã' (Musa sp. AAB group) were fused with protoplasts from nonembryogenic calli of`Lidi' (Musa sp. AA group). Direct somatic embryogenesis was observed when the fusion-treated protoplasts were cultured with rice nurse cells (Oryza sativa L. A-58 line). Somatic hybrids were identified by using random amplified polymorphic DNA (RAPD) markers. Forty-four primers were tested for polymorphism between the two parental varieties, and eleven of them showed polymorphism. Among the 13 regenerated plants from one experiment, 11 (85%) were identified as somatic hybrids by the presence of both parent bands, and 2 showed only the 'Lidi'-band patterns. From the other experiment, 5 of 11 regenerated plantlets (45%) were identified as somatic hybrids. Flow cytometric ploidy analyses showed different ploidy levels of the somatic hybrids.