Integrating resistance from wild relatives against downy mildew in Impatiens

Project Overview

Project Type: Graduate Student
Funds awarded in 2013: $14,999.00
Projected End Date: 12/31/2015
Grant Recipient: Cornell University
Region: Northeast
State: New York
Graduate Student:
Faculty Advisor:
Dr. Mark Bridgen
Cornell University

Annual Reports


  • Additional Plants: native plants, ornamentals


  • Crop Production: application rate management
  • Natural Resources/Environment: biodiversity, wildlife
  • Pest Management: genetic resistance
  • Production Systems: general crop production
  • Sustainable Communities: new business opportunities

    Proposal abstract:

    The advent of a virulent new race of downy mildew has defoliated and decimated impatiens across the United States, as well as worldwide. Often a key early season crop for small greenhouse growers and nurseries, and a fixture in landscapes and home gardens, susceptibility appears to be near-universal in the common species, I. walleriana. While the New Guinea types (I. hawkeri) appear resistant, they have drastically different cultivation requirements and methods. Unfortunately, they also do not form viable hybrids with the common species. However, preliminary data suggests that other, compatible species may be resistant and useful for breeding new, more diverse forms. We intend to screen a wide range of impatiens species for durable, input-independent resistance, and attempt hybrids between these and the common species. In addition, we will be looking at the degree of susceptibility in populations of native and naturalized impatiens species, such as the jewelweeds, and assessing the risk that they might become reservoirs for the disease. Concurrently, we will also investigate the potential of other, easy-growing species of impatiens to fill the garden niche held by I. walleriana, diversifying the range of species cultivated and providing more options for growers and gardeners.

    Project objectives from proposal:

    1. Screen approximately 30 impatiens species for reaction to impatiens downy mildew.
    2. Observe reaction of different populations of native jewelweed species to downy mildew.
    3. Hybridize identified resistant species with common impatiens to introgress resistance.
    4. Assess the success of hybridization process and the downy mildew resistance and consumer appeal of interspecific hybrids.
    5. Hybridize various impatiens species to identify hybrids with potential for seed-propagation as an alternative to common impatiens.
    6. Identify and create mutants for various impatiens species and evaluate how they may expand and benefit cultivation of the species.
    7. Present information on resistant species, and their use as landscaping alternatives, to gardeners, growers, extension personnel, and representatives from industry.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.