|NOWOGRODZKI, ANNA - Cornell University - New York|
|SCHAUB, MICHELLE - Cornell University - New York|
|REISCH, BRUCE - Cornell University - New York|
|LUBY, JAMES - University Of Minnesota|
|HEMSTAD, PETER - University Of Minnesota|
|SEEM, ROBERT - Cornell University - New York|
|GADOURY, DAVID - Cornell University - New York|
Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2013
Publication Date: 5/1/2013
Citation: Cadle Davidson, L.E., Nowogrodzki, A., Schaub, M., Reisch, B., Luby, J., Hemstad, P., Seem, R., Gadoury, D. 2013. Quantitative phenotyping of powdery mildew resistance in grapevine reveals differences in host resistance biology. American Phytopathological Society Abstracts. Phytopathology 103:S.
Technical Abstract: The recent demonstration of race-specific resistance to Erysiphe necator has encouraged grapevine breeders to identify and introgress quantitative resistance genes exhibiting complementary mechanisms. In 2012, we established a phenotyping center (VitisGenPM) for detailed evaluation of resistance to powdery mildew, based on quantitative microscopic analysis of single-isolate inoculations as part of a project supported by USDA-SCRI (www.vitisgen.org). By phenotyping detached leaves received from breeding programs. VitisGenPM provides replicated testing of resistance segregation among progeny for association analysis with high-density genetic markers. Thus far, the sample processing and data collection pipeline has logged over 120,000 microscope observations across seven mapping populations. Each mapping population revealed different aspects of resistance biology, likely due to different host genetics. For instance, Vitis hybrid ‘Horizon’ x V. rupestris ‘B38’ segregated independently for quantitative resistance to penetration and to microcolony formation. In contrast, V. hybrid ‘MN1264’ x V. hybrid ‘MN1214’ showed segregation of quantitative resistance to penetration, but progeny expressed no posthaustorial resistance. By selecting individuals with complementary resistance mechanisms as parents for new cross-hybridizations, we hypothesize that the next generation of progeny will express stronger and more durable resistance.