ARS | Publication request: Selection for Run1-Ren1 dihybrid grapevines using microsatellite markers

Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 22, 2012
Publication Date: N/A

Interpretive Summary: Powdery mildew is a major fungal disease of grapes worldwide. Large quantities of fungicides are used to control powdery mildew at a considerable expense to grape growers. Genetically controlled resistance is a promising alternative to the recurrent application of chemicals. Researchers at Missouri State University, Springfield, MO; University of Missouri, Columbia, MO; Szent Istvan University, Godollo, and University of Pecs, Pecs, Hungary; and USDA/ARS Parlier, CA combined two different sources of powdery mildew resistance through traditional breeding; one from Muscadine and the other from Central Asian Vitis vinifera grapes. Using published and newly developed markers, seedlings were identified that contained genes from both sources of resistance. The combined resistance will be more durable in the field than the single forms of resistance alone. This germplasm will be the basis for the development of powdery mildew resistant table, raisin, and wine grapes.

Technical Abstract: The inheritance of Ren1 and Run1 powdery mildew resistance genes were tracked in a grapevine hybrid family using linked microsatellite markers. Segregation of the powdery mildew resistance phenotype was evaluated under in vitro and greenhouse conditions independently of the genotype data. Combined analysis of phenotypic and genotypic segregations confirmed that Ren1 and Run1 acted as single dominant loci and segregated independently without an observable distortion of segregation. Recombinant genotypes were detected in the Ren1 but not in the Run1 region, conforming earlier observations that crossover events between homologues chromosomes is suppressed around the Run1 locus. Two new candidates for Run1-linked microsatellite markers also were designed. Taken together, the results suggested that marker-assisted selection is a reliable and cost-effective way to identify hybrid genotypes that combine desired alleles and especially useful for identifying plants with 2 pyramided sources of powdery mildew resistance.