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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Research Project #433598

Research Project: Development of Potatoes with Improved Resistance to Soil-Borne Diseases

Location: Temperate Tree Fruit and Vegetable Research

Project Number: 2092-21220-002-15-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2017
End Date: Aug 31, 2020

Objective:
Potato quality, appearance, yield and profitability can be severely impacted by soil-borne diseases including Corky ringspot disease (CRS) caused by Tobacco rattle virus (TRV) and vectored by stubby root nematodes (Paratrichodorus spp. and Trichodorus Spp.), Columbia root-knot nematode, potato cyst nematode, black dot, Verticillium and Potato mop top virus (PMTV) vectored by powdery scab. Soil-borne pests also increase the cost of production and necessitate expensive fumigation regimes. This work aims to improve our knowledge of these diseases and pests to provide methods useful for their control and to assist in the development of new cultivars with improved resistance to these pathogens and pests.

Approach:
Multiple approaches will be used to achieve our objectives. One limitation for developing resistant cultivars to TRV and PMTV is the lack of fields with consistent disease pressure and long term availability for screening candidate germplasm to identify new lines with resistance. We will explore ways to establish research fields with high disease pressure, especially for TRV and PMTV, emerging diseases of growing concern to growers. TRV and stubby root nematodes will be introduced into a new research field by transferring soil from a field known to be infested with viruliferous stubby nematodes, followed by planting a highly susceptible host crop to bulk up the numbers. The natural occurrence of black dot and Verticillium will be monitored, and if necessary additional inoculum will be introduced. Different approaches will be used to explore ways to introduce powdery scab into a separate field. As an obligate parasite, this will be a more challenging undertaking. We will identify industry fields with high powdery scab pressure, preferably also with PMTV, and use tubers from these fields as a source of inoculum. Molecular methods will be developed that can more accurately and efficiently detect and quantitate pathogens in the soil. To identify the basis of CRS resistance, progeny of a cross between TRV resistant and susceptible parents will be screened for their disease response and segregation of resistance. Potato cyst nematode is a quarantine pest found in a small area of Eastern Idaho in 2007. To examine potential ways to control or eradicate PCN, the use of partially purified hatching factors will be examined. Potato plants and root exudates will be used from which to extract hatching factors. Potato extracts will be partially purified, then tested for their efficacy stimulating hatch of PCN eggs in microplate hatching assays.