Plant Genome IV Conference Plant Genome IV Conference
Genetic maps were constructed for the parents of two inter-specific hybrid Vitis populations. Maps consisted primarily of RAPD markers, but also included RFLP and isozyme loci. Linkage maps for three of the four parents consisted of 19 groups as expected for Vitis where 2n = 38. There were 20 groups in the fourth parent. Map length in each of the four parents totaled between 1059 and 1477 cM, with between 182 and 225 markers on each map, and an average distance of about 6 cM between markers. QTL and joint segregation analysis was used to locate linkage group regions with effects upon powdery mildew and Botrytis rot resistance; flower type; berry shape; and other traits. In one map, a region with a major influence (LOD=5.7) on powdery mildew resistance was located. RAPD markers were characterized as having single copy as well as repetitive sequences. Current work focuses on developing marker assisted selection protocols for enrichment of disease resistance in seedling populations. SCAR markers have also been developed from selected RAPD bands in order to anchor individual linkage groups. Linkage maps developed in unrelated populations might then use these SCARs to establish homology with previously published maps.