A comprehensive collection and regeneration strategy for ex situ conservation
2002
Lawrence, M.J.
Because the facilities in genebanks are likely to be quite limited, it will usually be possible to raise only small populations of plants when producing fresh seed. These populations need to be large enough, however, to reduce the effects of drift on the erosion of genetical variation to an acceptable level. Calculations show that a sample size of 12 plants is probably sufficient to meet this objective provided that a biparental mating procedure is used to produce fresh seed. It is argued that for conservation, there is little point in collecting more seed from the source populations of the species in question than can be handled when regenerating this seed. If the species is regarded as the unit of conservation, this minimum sample size in the gene bank should determine the size of the sample collected from each population of the species. Provided that the product of this sample size and the number of populations from which material is collected is not less than 172, this strategy should ensure the conservation of all or very nearly all of the polymorphic genes that are segregating in the species. A critical analysis of current regeneration procedures shows that these are very inefficient and that much genetical variation is lost almost as soon as it is captured. Lastly, it is shown that some recent criticisms of the collection strategy proposed in earlier papers are misplaced.
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