A composite map of expressed sequences and phenotypic traits of the sunflower (Helianthus annuus L,) genome

A map of the sunflower genome, based on expressed sequences and consisting of 273 loci, was constructed. The map incorporates data from seven F-2 popu lations, for a total of 1115 individuals. Two hundred and fourty five loci corresponding to 170 anonymous cDNA markers and four loci for morphological markers were mapped. We also mapped 18 loci corresponding to previously de scribed genes or to sequences obtained through homology cloning. The unit m aps vary from 774 cM to 1060 cM, with an average value of 14 major linkage groups. The integrated mag is arranged in 17 major linkage groups including 238 loci, plus four small segments with 2-5 marker loci; and covers 1573 c M with an overall average marker interval of 7 cM. Thirty five percent of t he markers were dominant in nature and 30% showed inter-linkage group dupli cation without any indication of homoeologous linkage groups. Evidence is p rovided for the independence of two distinct fertility restoration genes, f or the presence of two loosely linked branching loci, and for marker tightl y linked to the Rf1 restoration locus. This map provides an efficient tool in breeding applications such as disease-resistance mapping, QTL analyses a nd marker-assisted selection.