Progress Toward the Development of Diploid Recombinant Inbred Lines

Recombinant inbred lines (RILs) offer new germplasm resources for mapping traits in potato.  They also provide an opportunity to evaluate responses to inbreeding in interspecific hybrids.  We are developing a set of six RILs, which will comprise a nested association mapping population.  The common parent is M6, an inbred line of the diploid wild relative Solanum chacoense.  It is homozygous for a dominant self-incompatibility inhibitor.  Other germplasm in the RILs includes S. tuberosum Tuberosum Group, S. tuberosum Phureja Group, and S. berthaultii.   The parents of the RILs have been selected based on tuber morphology and yield, disease resistance, and processing quality.  We plan to create 100 F6 inbred lines of each of the six RIL populations.  Currently, we have populations ranging from the F2 to F6 generations.  The DM1-3 x M6 F2 population has been used to map 10 genes associated with skin and flesh color, tuber shape, anther development, jelly end, and the presence of eye tubers instead of normal sprouts. During inbreeding, a reduction in vigor has been observed, as expected.  However, the major challenge is maintaining adequate flower production and fertility for seed production. The RILs will be shared with the research community for phenotyping and mapping.