Natural infection of <i>Run1</i>-positive vines by naïve genotypes of <i>Erysiphe necator</i>

Authors

  • L. Cadle-Davidson
  • S. Mahanil
  • D. M. Gadouri
  • P. Kozma
  • B. I. Reisch

DOI:

https://doi.org/10.5073/vitis.2011.50.173-175

Keywords:

powdery mildew, disease resistance, molecular markers

Abstract

The Run1 locus for dominant resistance to powdery mildew (Erysiphe necator) has been successfully introgressed into Euvitis from Vitis rotundifolia. In the current study, Run1 vines were hybridized with breeding lines at Cornell University, and the presence of the locus was assayed using the markers GLP1-12 and VMC8g9. Signs of powdery mildew were observed on 14 of 113 Run1-positive seedlings in October 2010 in Geneva, N.Y. Severity of infection was lower for Run1-positive than for Run1-negative seedlings. Presence of mature cleistothecia suggested infection by at least two pathogen genotypes, which since V. rotundifolia is not grown within 800+ km of Geneva, N.Y., evolved from a pathogen population naïve to Run1 resistance. Therefore, caution in the deployment of the Run1 locus in new resistant cultivars is suggested so the effectiveness of Run1 does not diminish over time.

 

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Published

2015-04-02

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