An integrated high density RFLP-AFLP map of tomato based on two Lycopersicon esculentum x L-pennellii F2 populations

Two independent F-2 populations of Lycopersicon esculentum x L. pennellii which have previously been investigated in RFLP mapping studies were used for construction of a highly saturated integrated AFLP map. This map spanned 1482 cM and contained 67 RFLP markers, 1078 AFLP markers obtained with 22 EcoRI + MseI primer combinations and 97 AFLP markers obtained with five PstI + MseI primer combinations, 231 AFLP markers being common to both populations. The EcoRI + MseI AFLP markers were not evenly distributed over the chromosomes. Around the centromeric region, 848 EcoRI + MseI AFLP markers were clustered and covered a genetic distance of 199 cM, corresponding to one EcoRI + MseI AFLP marker per 0.23 cM; on the distal parts 1283 cM, were covered by 230 EcoRI + MseI AFLP markers, corresponding to one marker per 5.6 cM. The PstI/MseI AFLP markers showed a more even distribution with 16 PstI/MseI AFLP markers covering a genetic distance of 199 cM around the centromeric regions and 81 PstI/MseI AFLP markers covering a genetic distance of 1283 cM on the more distal parts, corresponding to one marker per 12 and 16 cM respectively. In both populations a large number of loci showed a significant skewed segregation, but only chromosome 10 loci showed skewness that was similar for both populations. This ultra-dense molecular-marker map provides good perspectives for genetic and breeding purposes and map-based cloning.