|Del Rio, Alfonso - DEPT OF HORT UW MADISON|
Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: May 17, 1999
Publication Date: N/A
Technical Abstract: Crop genebanks wish to preserve genes for breeding use, so genebank managers must be concerned with preserving low frequency alleles that are vulnerable to accidental loss from the genebank. Mathematical models and recommendations that follow from hypothetical vulnerable alleles have been made. This work was undertaken to measure the actual prevalence of such alleles in the US Potato Genebank by extrapolation from RAPD markers. Two outcrossing species were selected, Solanum jamesii Torr. (2n=2x=24) and Solanum sucrense Hawkes (2n=4x=48). RAPD banded-plant frequencies for a total of 85 marker loci within each of 15 populations were assessed using 24 plants per population. For both species, about 10 percent of within-population bands were vulnerable (frequency less than 40 percent), considering just the particular population in question. However, about half of these were fixed (therefore invulnerable) in at least one other population. The highest within-population frequency for bands not fixed in any population was, with one exception, always greater than 40 percent. So, while many RAPD alleles are vulnerable within populations, these are nearly always fixed or nearly fixed (invulnerable) in another population. This indicates that the most effective strategy for conserving all alleles is to apportion available resources among many separate Mendelian populations rather than to select a representative few for rigorous attention.