Saturation mapping of the apple scab resistance gene Vf using AFLP markers

Using the amplified fragment length polymorphism (AFLP) technique combined with a "narrow-down" bulk segregant strategy enabled us to quickly identify 15 tightly Linked AFLP markers to the Vf gene that confers resistance to t he apple scab disease. High-resolution mapping placed all 15 AFLP markers w ithin an interval of 0.6 cM around the Vf region; 7 of them were Found to b e inseparable from the Vf gene, I was localized left of, and the remaining 7 located right of the Vf gene. In addition, eight previously identified RA PD markers were also mapped, but only three, including M18, AM19, and AL07, were localized within this short interval, and none co-segregated with the Vf gene. The saturation of the Vf region with AFLP markers will accelerate both marker-assisted selection and map-based cloning. The advantages of th is "narrow-down" strategy, estimation of physical distances among AFLP mark ers, and their potential application are also discussed.