ARS | Publication request: RAPD ANALYSIS OF GENETIC DIVERSITY IN SOLANUM POPULATIONS TO PREDICT THE NEED FOR FINE SCREENING

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 16, 2000
Publication Date: N/A

Interpretive Summary: Aphids and the virus diseases they carry are a major problem for potato growers. They reduce yields, require costly control measures, and can make the crop unacceptable for seed. Breeding genetic resistance into new varieties is an attractive solution to this problem. Certain populations of wild species' relatives of potato with potent resistance have been identified. While these populations should be good sources of resistance, plants within these populations might be variable, with some plants significantly more resistant than others--and thus better parents for use in breeding. But if the DNA of individual plants was very uniform, resistance to aphids and viruses probably would be uniform within populations too. When tested, about 20% of the DNA markers were variable within the resistant populations, indicating that these plants are far from genetically uniform. Thus, individual plants from within these populations should be tested for resistance. This will allow breeders to identify and use parents with the best resistance genetics.

Technical Abstract: Two wild potato species populations known to have high levels of green peach aphid, PLRV and PVX resistance (Solanum polytrichon PI 184170, S. stoloniferum PI 160226), were assessed for heterogeneity of RAPD markers among plants within the populations and among other populations of their species. Had these facultative selfers been determined to be highly uniform inbreds, there would be little need for fine screening (at the individual plant level) before proceeding with breeding crosses. However, these populations expressed more than 20% of the RAPD band variability detected among various populations of their species. Thus, significant variation for insect and virus resistance among individual plants is a possibility, and fine screening of these materials at the genotype level is recommended to identify the optimum parents.