A GENOMIC LIBRARY OF LYCOPERSICON PENNELLII IN LYCOPERSICON-ESCULENTUM - A TOOL FOR FINE MAPPING OF GENES

The cultivated tomato contains only a small fraction of the genetic va riation present in its wild relatives. In order to use the wild germpl asm in tomato breeding and genetic studies we developed a new kind of genetic resource which is composed of 50 L. esculentum lines each cont aining a single introgression from the green fruited species L. pennel lii (LA 716). Each of the introgression lines is nearly isogenic to th e cultivated tomato; these lines provide complete coverage of the wild species genome. The lines contain on the average an introgression of 33 cM from a total genome size of 1200 cM. The size and identity of th e introgressed segments was determined based on RFLP analysis of 350 m arkers. This resource can be viewed as a genomic library of the wild s pecies in the cultivated background. It covers the entire genome with single independent 'inserts' per line and therefore every phenotypic d ifference between the introgression lines can be associated with the u nique introgressed segment. The development and potential application of this resource are discussed.