CONSTRUCTION OF A MOLECULAR LINKAGE MAP OF PEPPER AND A COMPARISON OFSYNTENY WITH TOMATO

A molecular map of pepper (Capsicum sp.) totalling 720 cM has been con structed in an interspecific F2 cross with restriction fragment length polymorphisms and isozymes. Nineteen linkage groups were formed from 192 molecular markers. Twenty-six markers showed no linkage to any oth ers. Twenty-eight markers showed significant deviation from expected M endelian ratios and clustered in the genome. Two quantitative trait lo ci controlling the number of flowers per node were mapped to linkage g roup 10. The order of markers in at least 228 cM (31.7%) of the pepper genome is conserved with respect to the tomato genome, with a minimum of 15 chromosome breakage events postulated to have occurred since th eir divergence from a common ancestor. Comparisons of meiotic recombin ation in 14 conserved intervals indicates that tomato has a higher rat e of recombination than does pepper in the crosses studied. Evidence s uggests that centric fusions and resulting chromosome breakage events are mechanisms for genome evolution in the Solanaceae.