Author

Chen Li

Date of Graduation

Spring 2012

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Laszlo Kovacs

Keywords

marker-assisted selection, gene pyramiding, Erysiphe necator, Ren1, Run1, microsatellite

Subject Categories

Biology

Abstract

Powdery mildew is a major fungal disease of grapevine worldwide, and the control of which relies on large quantities of fungicide, accounting for a considerable cost for grape growers. Genetically controlled resistance is a promising alternative to the recurrent application of chemicals.The inheritance of Ren1 and Run1 powdery mildew resistance (R) genes were tracked in a grapevine hybrid family using flanking 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 assorted independently without considerable distortion of segregation. Recombinant chromosomes were detected in the Ren1 but not in the Run1 region, corroborating earlier observations that crossover events between homologous chromosomes are suppressed around the Run1 locus.Taken together, the results of this work show that microsatellite marker-assisted selection is a reliable and cost-effective method to combine multiple alleles that confer resistance to a pathogen.In addition, this work identified the progeny that inherited two R genes, which will be further crossed with a third powdery mildew R genes to develop a new table grape cultivar.

Copyright

© Chen Li

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