CRYOCONSERVATION OF POLLEN FOR GERMPLASM STORAGE AND FOR UTILIZATION IN BREEDINGPROGRAMMES

摘要

Long-term storage of pollen grains is a useful means of conserving haploid gene pool and is also considered ideal for overcoming temporal and spatial isolation of the parent species in the breeding programmes. Cryopreservation has been one of the effective methods of long-term pollen storage which has been attempted for diverse plant species in the present studies. For pre- and post-storage viability assessment, the most commonly used in vitro germination, method for testing the viability, has been used. Tetrazolium (TTC) test has also been conducted. Fluorochromatic Reaction (FCR) test was additionally conducted to test the presence of esterases in the cytoplasm and to check membrane intactness. Fertilizing ability of cryostored pollen is ideally the best method for pollen viability testing and which has been used in the present studies. An improved method for pollen collection in mango (Mangifera indica L.) and litchi (Litchi chinensis Sonn.) using organic solvent cyclohexane has been devised. Using this method, pollen quantity sufficient for large scale pollinations could be collected and stored for future use. Four years cryostored pollen of different mango and litchi varieties and 6 months to 1 year cryostored pollen of Crotalaria, Brassica,Garcinia, Poncirus, Citrus, Abelmoschus and Cucumis spp. on retesting showed high percentage viability as good as fresh control pollen. Detailed studies on oil palm pollen led to success in cryostorage beyond 8 years. Retention of viability of cryostoredpollen of different species in studies carried out for last 10 years has indicated successful pollen cryoconservation.