A genetic linkage map for Stevia rebaudiana

To lay a foundation for molecular breeding efforts, the first genetic linka ge map for Stevia rebaudiana has been constructed using segregation data fr om a pseudo test-cross Fl population. A total of 183 randomly amplified pol ymorphic DNA (RAPD) markers were analysed and assembled into 21 linkage gro ups covering a total distance of 1389 cM, with an average distance between markers of of 7.6 cM. The 11 largest linkage groups consisted of 4-19 loci, ranged in length from 56 to 174 cM, and accounted for 75% of the total map distance. Fifteen RAPD loci were found to be unlinked. From the 521 primer s showing amplification products, 185 (35.5%) produced a total of 293 polym orphic fragments, indicating a high level of genetic diversity in stevia. M ost of the RAPD markers in stevia segregated in normal Mendelian fashion.