ISHS Acta Horticulturae 760: XXVII International Horticultural Congress - IHC2006: II International Symposium on Plant Genetic Resources of Horticultural Crops
ORCHID SEED STORAGE FOR GERMPLASM PRESERVATION |
| Authors: | A.M. Mweetwa, G.E. Welbaum, D. Tay |
| Keywords: | Brassia, Phalaenopsis, cryopreservation, genetic resources conservation, tissue culture, protocorms, genebank |
| Abstract:
Orchids are important ornamental, medicinal, and food plants. Orchids have fascinated people with their extraordinary beauty, their variation in size, color, and shape. Of the world's 25,000 orchid species, some 10% are endangered in their native habitats. There are currently no major government efforts to conserve orchid germplasm using seeds other than at the Ornamental Plant Germplasm Center of the USDA. There is a need to develop procedures to improve orchid seed storage for germplasm conservation for parts of the world where in situ conservation is not possible. The goal of this project is to develop a protocol for genebank storage of orchid seed and protocorms. Preliminary studies were conducted on the potential storability of Brassia and Phalaenopsis spp. seeds. The seeds were stored at –196ºC (liquid nitrogen), –80, –18, 4 or 25ºC to determine the optimum conditions for short- and long-term storage. Phalaenopsis and Brassia seeds, adjusted to 45.5% RH over saturated chromium dichromate solution, were able to survive 10-day storage at –80ºC or 4ºC. Seeds frozen in liquid nitrogen for 30 min were able to germinate and produce protocorms 19 d after sowing. Liquid nitrogen storage also improved germination and seedling development of some Phalaenopsis seed lots from 0 (control) up to 37%. Storing Phalaenopsis seeds improved germination similarly, suggesting dormancy was broken by low temperature treatments. On the other hand, seeds stored at 25ºC did not germinate. Preliminary results suggest that orchid seeds tolerate freezing even in liquid nitrogen and that cryopreservation may be a viable long-term strategy for orchid germplasm preservation. | |
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