Development of conservation strategies for Citrus species of importance to Australia

Abstract

Australian Citrus species have socioeconomic value either as commercially significant fruit crops or as wild relatives of major fruit crops. Long-term conservation of germplasm of these species is important to ensure future access to genetic material for plant improvement projects. An in vitro culture system would allow the mass propagation of these species and assist breeding and conservation programs. In this study, plant regeneration from in vitro nodal cuttings of three Australian Citrus species was achieved. Somatic embryogenesis was also investigated in both cultivated varieties of local importance and native citrus varieties using ovules and seeds. The polyembryonic commercial cultivars (Murcott and Orlando) produced prolific embryogenic callus and somatic embryos that regenerated into plants. C. inodora the only Australian species to form somatic embryos. This embryogenic protocol provided material for a preliminary trial of cryopreservation in C. inodora.