Citrus somatic hybrids regenerated from protoplast electrofusion.

摘要

Citrus genetic improvement through conventional methods is greatly hindered by nucellar polyembryony, pollen and/or ovule sterility, and wide incompatibility. Protoplast fusion is an alternative that can be used to circumvent these difficulties andefficiently transfer resistances to biotic and abiotic stress to commercial scion cultivars and rootstocks. More than 20 interspecific, intergeneric, and intertribal somatic hybrids have recently been obtained in our programme by electrically induced fusion. The hybrids include those from elite scion cultivars such as Bonanza navel orange + Red blush grapefruit, Newhall navel orange + Eureka lemon, Newhall navel + Kuigan, Kinnow + Bendizao tangerine, and those from complementary rootstocks such as red tangerine + trifoliate orange, red tangerine + rough lemon, red tangerine + citrange. Fusion between Citrus and its wild relatives such as Page tangelo + Murraya paniculata and C. sinensis + Clausena lansium (6x) regenerated allo-tetraploid and allo-hexaploid plants, respectively. By standard symmetric fusion, diploid mesophyll parent type plants (putative cybrids) from more than ten combinations were also regenerated. To verify their hybridity, all the regenerants were identified by morphology, cytology, isoenzyme analysis and random amplified polymorphic DNA (RAPD) analysis.