PAG-IV Plant Genome IV Conference

Town & Country Conference Center, San Diego, CA, January, 1995.

P191
Comparison of Vernalization Responsive Flowering Time Genes in Brassica rapa, B. napus AND Arabidopsis thaliana

T. OSBORN(1,2), C. Kole(2), I. Parkin(2), D. Lydiate(2), M. Trick(2) and M. Kuiper(3)
1. University of Wisconsin, Madison, WI 53706, USA
2. John Innes Centre, Colney, Norwich NR47UH, UK
3. KeyGene, P.O. Box 216, 6700 AE Wageningen, The Netherlands

Genes that control flowering time and are responsive to vernalization treatment have been mapped in Brassica rapa and B. napus using crosses of annual and biennial cultivars. Evidence for homology of these genes between the species was obtained by comparing their map positions using common RFLP and AFLP loci. The results suggest that the two major genes controlling most of the variation for flowering time in the B. rapa population correspond to the two major genes controlling this trait in the B. napus population. Brassica rapa is a diploid and one of the hypothesized parents of the amphidiploid B. napus. Thus, the vernalization requirement of the biennial B. napus cultivar used in this study appears to have originated from B. rapa. The two major Brassica genes also were compared to flowering time genes in Arabidopsis thaliana by mapping RFLP loci with the same probes in both B. napus and A. thaliana. One region containing a Brassica gene showed homology to the top of chromosome 5 in A. thaliana where the flowering time genes co, fy and flc are located. The second region showed homology to the top of chromosome 4 where fri is located. Thus, these Brassica genes may correspond to the two major vernalization responsive flowering time genes (flc and fri) found in natural late flowering ecotypes of A. thaliana.

Return to Previous Page or Intl-PAG Homepage