Project Number: 1275-21220-187-07
Project Type: Specific C/A

Start Date: Jul 30, 2003
End Date: Jul 30, 2006

Objective:
The objective of the program will be to evaluate new potato lines and wild species related to potato for their resistance to the disease. Progeny of the resistant lines will also be tested for the transmission of the resistance to the progeny. Finally, particularly resistant and fertile lines will be selected for an international effort to produce potato cultivars which yield well, are adapted to the many areas of potato cultivation and which are sufficiently resistant to disease so as to provide good crops without heavy pesticide applications.

Approach:
A whole-plant field test, as described by Stewart et al. (1983), will be used to determine which of the U.S. clones have inherited resistance genes and which have not. Plants of each clone in flower bud will be exposed or inoculated with the virulent race of the P.infestans. Race 1,3,4,7,10,11 is the most virulent available. Each plant will be scored using Malcolmson's scoring scale of increasing resistance (Cruickshank et al., 1982) 7 days after inoculation, and plants of each clone compared. Clones will be considered to be R-gene-free if there are spreading lesions in response to the inoculum. They will be considered to have inherited the R-gene if the plants inoculated with the virulent race are symptomless, or have only isolated necrotic lesions or isolated spreading lesions on the oldest leaves alone, while those inoculated with the virulent race have numerous spreading lesions. Cruickshank G, Stewart HE, Wastie RL, 1982. An illustrated assessment key for foliage blight of potatoes. Potato Research 25, 213-4. Stewart HE, Flavelle PH, McCalmont DC, Wastie RL, 1983. Correlation between glasshouse and field tests for resistance to foliage blight caused by Phytophthora infestans. Potato Research 26, 41-8.

Project Team

Deahl, Kenneth Hector Lozoya-Saldana - Technical Director 301-504-7380

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Plant Diseases (303)