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POSTERS: Genetics of resistance

Characterizing the genetic basis of silver scurf resistance in the diploid potato clone ‘C287’
Sofía Macchiavelli-Girón - University of Wisconsin-Madison. Andy Hamernik- University of Wisconsin-Madison, Shelley Jansky- USDA ARS, Amanda Gevens- University of Wisconsin-Madison

Silver scurf of potato, caused by the fungus Helminthosporium solani, is a tuber blemish disease of great and increasing concern to the United States potato industry. There are currently no commercially available silver scurf-resistant cultivars, nor are there consistently effective cultural management practices. Previous studies have identified potato breeding clone C287 with resistance to silver scurf . We aim to determine the genetic attributes responsible for silver scurf resistance in C287. This work is useful for breeders, as they can integrate this resistance into their breeding programs to further enhance management of this disease. C287 was crossed with M6, a diploid self-compatible inbred line of the potato wild relative Solanum chacoense, which is susceptible to silver scurf. From the progeny, F1-22 was selected (based on disease resistance and tuber type) and self-pollinated to create 135 F2 plants. Replicated inoculated field trials were conducted in 2017 and 2018 to screen for resistance. Preliminary results indicate that there are significant differences among F2 clones, including tuber weight and number, indicating that segregation occurred for these traits in this population. Disease symptoms were not visually apparent, so quantitative PCR was used to quantify pathogen presence. Results show variation in resistance between F2 clones. We will use single nucleotide polymorphisms to look for quantitative trait loci associated with silver scurf resistance. This will determine whether a marker for silver scurf resistance can be identified in potato.