ISHS Acta Horticulturae 623: XXVI International Horticultural Congress: Plant Genetic Resources, The Fabric of Horticulture's Future
GERMPLASM PRESERVATION IN ALLIUM SPECIES: AN INTEGRATED APPROACH TO STORE MORPHOLOGICALLY CHARACTERISED VIRUS-FREE PLANT MATERIAL VIA CRYOPRESERVATION |
| Authors: | E.R.J. Keller, A. Senula |
| Keywords: | garlic, shallot, genebanking, meristem culture, vitrification |
| Abstract:
A large collection of Allium crop and wild species is maintained at Gatersleben. Additionally to the field maintenance, in vitro culture and cryopreservation are used to increase the maintenance safety and plant quality. One third of the 3500 Allium accessions are held vegetatively. Vegetative maintenance of germplasm is usually accompanied by virus accumulation. Onion yellow dwarf (OYDV), leek yellow stripe (LYSV), garlic common latent (GCLV), shallot latent (SLV) and allexiviruses have been detected by ELISA and tissue print. Virus susceptibility is species-specific. Together cultivated A. albidum, A. globosum, A. hymenorrhizum, A. lineare, and A. obliquum were more infected than A. rubens, saxatile, and senescens. Similar differences were found in their hybrids with A. cepa. Virus elimination is performed by meristem culture partly in combination with chemotherapy. Virus elimination is better in shallot (82.2% of 191 tested plants) than in garlic (34.6% of 379 tested plantlets). In garlic, it was possible to establish a virus-free core collection of the most important accessions. This collection has been described by internationally standardised morphological descriptors. Cryopreservation methods are in development for garlic. The cryoprotectant mixture PVS3 (50% glycerol + 50% sucrose) is used. For cryopreservation, meristematic regions of the plants are used. Differences were found in plantlet regeneration with respect to the source organs - ripe cloves, bulbils of different age and size, in vitro cultures. Explants from cloves regenerate well, but they suffer from contamination. Therefore, bulbils are the most frequently used organs. Finally, in vitro cultures offer the chance to use virus-free material for storage, but cryopreservation of them is still difficult. Therefore, several pre-treatments will be necessary such as dehydration and cold hardening. | |
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