ARS | Publication request: GENETIC HETEROGENEITY AMONG BREEDING SYSTEMS OF POTATO SPECIES AND ITS RAMIFICATIONS IN GERMPLASM CONSERVATION

Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: March 19, 2001
Publication Date: N/A

Technical Abstract: Most germplasm in the US Potato Genebank is in the form of botanical seed populations. So, depending on the breeding system, plants within these populations may be highly heterozygous and heterogeneous. Or, if they are facultative selfers, they may be homozygous and perhaps also homogeneous. The population structure in this sense has a great impact on germplasm conservation and use. Specifically, the more heterogeneous plants within a populations are, the more care needs to be taken to avoid losing genes when that population is sampled for original collection, genebank multiplication, or evaluation for economic traits. This study used RAPD markers to investigate genetic heterogeneity (GH) among 18-24 plants in each of 21 potato populations from 3 species. These represented three different breeding systems observed in Solanum species: S. jamesii (diploid outcrosser), S. fendleri (disomic tetraploid selfer) and S. verrucosum (diploid selfer). Plants within all populations of selfing S.verrucosum and S. fendleri were very homogeneous (GH = 0.036 and 0.082, respectively). In contrast, outcrossing S. jamesii populations were all much more heterogeneous (GH= 0.295). This pilot study demonstrates the usefulness of RAPD markers to gain insights into population structure and thereby optimize the efficiency of germplasm preservation and use. A more comprehensive study is in progress.