|Thompson, Asunta - NDSU, FARGO, ND|
|Taylor, Raymond - NDSU, FARGO, ND|
|Pasche, Julie - NDSU, FARGO, ND|
|Gudmestad, Niel - NDSU, FARGO, ND|
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 22, 2006
Publication Date: May 1, 2007
Citation: Thompson, A.L., Taylor, R.J., Pasche, J.S., Novy, R.G., Gudmestad, N.C. 2007 Resistance to Phytophthora erythroseptica and Pythium ultimum in a potato clone derived from S. berthaultii and S. etuberosum. American Journal of Potato Research 84:149-160 Interpretive Summary: Pink rot and potato leak are two important soil-borne diseases of potato. Screening of potato germplasm for resistance to pink rot identified several breeding clones that had desirable levels. A pink rot resistant, breeding clone, Etb 6-5-2, also was found to have a high level of resistance to potato leak. Etb 6-5-2 is unique in having resistances to both diseases. The sources of resistance are thought to be two wild potato species, Solanum etuberosum and S. berthaultii. Etb 6-5-2 can be useful as parental material for the development of potato cultivars resistant to both pink rot and leak.
Technical Abstract: Tubers of several potato clones and cultivars were screened for susceptibility to infection by zoospores of Phytophthora erythroseptica and mycelia of Pythium ultimum over a three year period, from 2003-2005. Incidence of infected tubers (%) and penetration of rot (mm) were the parameters used to determine the susceptibility of each potato clone. Responses of each potato clone were compared to cultivars with known resistance or susceptibility to these pathogens. Tubers of cultivars Atlantic and Snowden have moderate resistance to infection and colonization by P. erythroseptica and P. ultimum, respectively, and were used as the resistant checks. Cultivars Russet Norkotah and Red Norland are susceptible to infection by both pathogens. A number of potato clones demonstrated resistance to pink rot equal to or greater than the control cultivar Atlantic, including Etb 6-5-2, ND5822C-7, ND6056b-13, ND7443Ab-44, ND7443Ab- 181, ND7818-1Y and J101K6A22. In addition to demonstrating the highest resistance to pink rot, Etb 6-5-2 was the only clone which demonstrated resistance to leak greater than or equivalent to the resistant cultivar Snowden. Etb 6-5-2 is a backcross derivative from a somatic hybrid of Solanum etuberosum and Solanum berthaultii and will be an excellent source of genetic resistance to these two storage rot diseases.