ARS | Publication request: Unbalanced bulk of parent’s seed is not detrimental in potato germplasm regeneration

Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2007
Publication Date: February 1, 2008
Citation: Del Rio, A., Bamberg, J.B. 2008. Unbalanced bulk of parent’s seed is not detrimental in potato germplasm regeneration [abstract]. American Journal of Potato Research. 85:28.

Technical Abstract: Although cultivated potato, Solanum tuberosum is a clonal crop, genebank maintenance is commonly done as populations of true seeds. To help prevent genetic drift, some recommend bulking equal number of seeds from each mother plant for use in subsequent regeneration cycles. To assess whether this is an advantage, we selected two S. andigena populations with great variation of seed production among mothers. Seed production was recorded over 12 regenerations and 105 polymorphic RAPDs were used as genetic indicators. For each polymorphic band, variation of seed production per mother was used to predict change in banded egg frequency in regenerations. Assuming pollen success equal to egg success; probability of excluding bands from a 20-plant sample was calculated and compared before and after regeneration. Only a fraction of bands were polymorphic within populations and thus vulnerable to change in frequency or exclusion. Most of the remaining bands were present in several mothers, making their vulnerability very low. Of the remaining bands vulnerable within one population, most were fixed or nearly fixed in the other. Only 4 bands would have been substantially less vulnerable to loss; average improvement was only 23%. Balancing seed from mothers does not control differences in male contribution, and cannot remedy loss of a band when that band is unique to a parent that produces no seeds at all. For balanced bulks to provide a significant preservation advantage a band must be relatively rare in all populations and associated with a mother that produces significantly fewer seeds. Very few bands meet these conditions. Hence, duplication of documentation and storage space invested in making balanced seed bulks probably pay back little genetic benefit to the genebank