L. pennellii Introgression lines (ILs)
Congenic lines that differ in a single defined chromosome segment are useful for the study of complex phenotypes, as they allow isolation of the effect of a particular quantitative trait locus (QTL) from those of the entire genome. We developed a set of Lycopersicon pennellii-derived introgression lines (ILs) that together cover the entire genome in the background of L. esculentum Var. M82. This resource is very powerful for the study of genes affecting complex phenotypes.
The second generation IL population is composed of 76 ILs (the 50 original lines and 26 new ILs), each containing a single introgression from L. pennellii (LA 716) in the genetic background of the processing tomato variety M82. The IL map was connected to the high-resolution F2 map composed of 1500 markers. This was achieved by probing all of the specific chromosome lines with the RFLP markers from the framework F2 map. A total of 614 markers were probed and the ends of the introgressions were mapped with the resolution of the F2 map.
The L. pennellii introgressed segments appear as solid bars in which the boundary edge of each segment is indicated by inclusive (+) and exclusive (-) RFLP markers. All ILs are homozygous for the introgressed segment except for part of IL8-1 (dashed line). Bins are designated by the chromosome number followed by a capital letter and indicate a unique area of IL overlap and singularity; it is important to note that some of the bin designations might change as more probing is done. Molecular and genetic markers are indicated to the right of each chromosome and the genetic distances (in cM) according to Tanksley et al. (1992) are indicated to the left.
Seed of the second generation ILs is presently being increased by The C.M. Rick Tomato Genetics Resource Center, University of California Davis and the ILs were assigned accession numbers LA4028 - LA4103.
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