Plant & Animal Genome IX Conference

Poster: Maize, Sorghum, Sugarcane
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FINE MAPPING OF MARKERS LINKED TO SCMV RESISTANCE LOCI Scmv1 AND Scmv2 IN MAIZE

Institute of Plant Breeding, Seed Science, and Population Genetics, University of Hohenheim,70593 Stuttgart, Germany

Sugarcane mosaic virus (SCMV) is one of the most important virus diseases of maize in Europe. In field and greenhouse experiments, three dent inbreds (D21, D32, FAP1360A) displayed complete resistance against SCMV, MDMV, and other potyviruses after artificial inoculation. QTL analyses in cross D32 x D145 detected two major resistance genes, designated Scmv1 on chromosome 6 and Scmv2 on chromosome 3. Fine mapping of Scmv1 and Scmv2 regions has been initiated using 54 AFLPs in a bulked segregant analysis of cross FAP1360A x F7 backcrossed five times to F7 with selection for SCMV resistance each second generation. A total of 23 linked AFLP markers were identified, clustering on chromosome regions adjacent to either Scmv1 or Scmv2. Application of a Four-Step-Strategy (FSS) allowed quick identification of linked AFLP markers in narrow chromosomal segments of < 14 cM length including each of both resistance genes. Applying 458 AFLP primer combinations in FSS using symptomless BC7 and BC9 individuals of cross FAP1360A x F7 we identified additional 30 AFLP marker bands closely linked to either Scmv1 or Scmv2. In total, 512 AFLP primer combinations, 4 RFLPs, and 31 polymorphic SSRs were analysed, yielding 88 markers associated with either Scmv1 or Scmv2. Those markers were mapped with the software CRI-MAP using a BC population consisting of 214 BC1 to BC9 individuals. Cosegregating or tightly linked markers are used for development of STS markers for marker-assisted selection as well as for map-based cloning of these genes.