Somatic hybrids between navel orange (Citrus sinensis) and grapefruit (C. paradisi) for seedless triploid breeding

摘要: Protoplasts from cell suspension cultures of ‘Bonnaza’ navel orange (Citrus sinensis (L.) Osbeck) were electrically fused with mesophyll protoplasts isolated seedless ‘Red Blush’ grapefruit (Citrusparadisi). After 6 months culture, a total 20 plants regenerated. Root tip chromosome counting revealed that 4 them tetraploids (2n = 4x 36)and the rest diploids 2x 18) morphologically resembling parent. transplantation into greenhouse, diploidmesophyll regenerants unexpectedly flowered, but this phenomenon disappeared in next year. This is first report precocious flowering citrus via protoplast fusion. RAPD analysis further confirmed tetraploid somatic hybrids while diploid parent type. hybrid will be utilized as possible pollen for improving seedy pummelo cultivars China by producing triploid hybrid. The mechanism early was also discussed.