Development of advanced technologies for germplasm conservation of tropical species

Abstract

Tissue culture and cryopreservation protocols are being developed for a range of tropical fruit species in Australia, Philippines, Vietnam, Thailand and Malaysia with the assistance of ACIAR (Australian Centre for International Agricultural Research) and IPGRI (International Plant Genetic Resources Institute). Included in the Australian program are the development of techniques for long-term cryo-storage of papaya (Carica papaya) shoot tips and mango (Magnifera indica) somatic embryos (SEs). Research on papaya shoot tip cryopreservation has included optimisation of many factors including: age of in vitro plants; duration of pre-culture of shoot tips prior to vitrification treatment; duration and temperature of PVS2- treatment; con죥ntration of growth regulators (BAP, GA3) in recovery medium post-cryopreservation; and, effect of light on recovery of shoots after cryopreservation. Success rates are genotype dependent, but recovery of between 60 and 70% of shoots has been obtained for some genotypes. For mango, SEs were induced from nucellar tissue of immature fruit. Rapid proliferation of secondary SEs has been achieved. Cryopreservation of SEs is at a preliminary stage, however live SEs have been recovered after liquid nitrogen (LN) treatments.