MOLECULAR MAPPING OF THE POTATO-VIRUS-Y RESISTANCE GENE RY(STO) IN POTATO

Ry(sto) is a dominant gene which confers resistance to potato virus Y (PVY) in potato. We have used bulked segregant analysis of an F-1 tetr aploid potato population to identify three AFLP markers linked to and on either side of Ry(sto). The tomato homologue of one of these AFLP m arkers was assigned to linkage group XI by analysis of an F-2 mapping population of tomato, suggesting that Ry(sto) is also on chromosome XI of the potato genome. This map position was confirmed by the demonstr ation that Ry(sto) was linked to markers which had been previously map ped to chromosome XI of the potato genome. Four additional AFLP marker s were identified that were closely linked to Ry(sto) in a population of 360 segregating progeny of a potato cross between a resistant (Ry(s to)) and a susceptible parent. Two of these markers were on either sid e of Ry(sto), separated by only a single recombination event. The othe r two markers co-segregated with Ry(sto).