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Title: CHARACTERIZATION OF PRATYLENCHUS PENETRANS FROM TEN GEOGRAPHICALLY ISOLATED POPULATIONS BASED ON THEIR REACTION ON POTATO

Author
item FRANCE, R - CORNELL UNIVERSITY
item BRODIE, BILL

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Root lesion nematodes can cause losses of 15 to 73% of marketable potato yields. These nematodes also interact with a fungal pathogen of potatoes causing a disease known as potato early dying which is a major constraint to potato production in the northern potato production areas of the United States. Traditionally, root lesion nematodes have been controlled with chemical nematicides. Issues concerning the safety of these nematicides t the environment and human health has forced a decline in their usage and a search for alternative means of controlling root lesion nematodes. The discovery of resistance in potatoes to root lesion nematodes opened new opportunities for developing environmentally safe controls. However, the possibility that strains of the nematode exist that can overcome resistance causes concerns about the practical use of host resistance for their con- trol. In this study we assessed differences in the parasitic behavior of ten geographically isolated populations of root lesion nematodes. We found that the ten populations were composed of four distinct strains that differed in their ability to parasitize potatoes. A potato clone that had been identified as resistant to our local strain of root lesion nematodes was found to be susceptible to the other three strains. These results point out an added level of complexity and difficulty in developing host resistance in potato as an alternative means of controlling root lesion nematodes.

Technical Abstract: Single female cultures of P. penetrans were established from soil and root samples collected from 10 geographically isolated locations in North America. The resultant isolates were used to evaluate nematode egression from and multiplication on roots of potato clones to distinguish intraspecific differences among isolates. The 10 isolates were statistically separated into 4 groups based on percentage of nematodes tha egressed from the P. penetrans resistant clone L118-2. The Cornell (CR), Wisconsin (WI), Long Island (LI), and Adirondack (AD) isolates were selected as representative isolates of each of the four groups. The CR WI, LI, and AD isolates exhibited 53, 39, 25, and 10% egression from l118-2, respectively. Reproduction of these 4 isolates was measured on 3 potato cultivars (Russet Burbank, Butte, and Hudson) and 2 breeding lines (NY85 and L118-2). The LI and AD isolates reproduced well on all 5 potato clones. The CR isolate reproduced well on Russet Burbank and NY85 but significantly less on Butte, Hudson, and L118-2. Reproduction of the WI isolate was less than the LI and AD isolates but more than the CR isolate on all potato clones tested except Russet Burbank. Reproduction of the WI isolate on Russet Burbank was less than the other three isolates. Based on these results, 4 distinct intraspecific variants of P. penetrans are proposed: Cornell, Wisconsin, Long Island, and Adirondack.