MOLECULAR MARKER ANALYSIS OF HELIANTHUS-ANNUUS L .2. CONSTRUCTION OF AN RFLP LINKAGE MAP FOR CULTIVATED SUNFLOWER

A detailed linkage map of Helianthus annuus was constructed based on s egregation at 234 RFLP loci, detected by 213 probes, in an F-2 populat ion of 289 individuals (derived from a cross between the inbred lines HA89 and ZENB8). The genetic markers covered 1380 centiMorgans (cM) of the sunflower genome and were arranged in 17 linkage groups, correspo nding to the haploid number of chromosomes in this species. One locus was found to be unlinked. Although the average interval size was 5.9 c M, there were a number of regions larger than 20 cM that were devoid o f markers. Genotypic classes at 23 loci deviated significantly from th e expected ratios (1:2:1 or 3:1), all showing a reduction in the ZENB8 homozygous class. The majority of these loci were found to map to fou r regions on linkage groups G, L and P.