REGENERATING PLANTS FROM CRYOPRESERVATED ADVENTITIOUS BUDS OF HAPLOIDS AND THEIR GENETIC STABILITY IN RICE

Alarge number of adventitious buds were induced from in vitro cultured young panicles of haploids of rice.The adventitious buds subcultured on solidified subculture media at 26℃ for 7 days were loaded into 18 mLplastic cryotubes with enough cryoprotectant and kept on ice for 45～60 min.After cooled at a rate of 1.0℃/min down to -40℃, the samples were plunged into liquid nitrogen.The adventitious buds cryopreserved for about 30 days were thawed rapidly in 38～40℃ water and then plated on solidified MSmedium containing 3% sucrose, 0.5 mg/L NAAand 2.0 mg/Lkinetin.After plated, 21%～29% of adventitious buds resumed growth and 14%～18% regenerated plantlets.The results of this work indicated that selecting adventitious buds derived from in vitro cultured young panicles is a critical factor for the success and subculturing adventitious buds on MSmedium containing 3% sucrose and 4% sorbitol or 20% potato extract is essential to the procedure.The effective cryoprotectant is 10% DMSO (dimethyl sulfoximide)+0.5 mol/Lsorbitol.Chromosome identifying of root tip cell and RAPDanalysis of regenerating plants indicated that the regenerating plants have good genetic stability.