|Brown, Charles - Chuck|
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2000
Publication Date: N/A
Interpretive Summary: The corky ringspot disease of potatoes is caused by the tobacco rattle virus. This virus is transmitted to potato from a multitude of other host plants by the stubby root nematode. Several years of testing was done at two sites in the Columbia Basin, where long growing seasons and sandy soils favor the disease. A number of resistant breeding selections and named varieties were shown to have very good resistance to corky ringspot in these tests. Greenhouse evaluations were then conducted in order to determine whether this was due to resistance to the nematode or to the virus. It was shown that corky ringspot resistance was due to the potato's reaction to the virus not the nematode.
Technical Abstract: Potato germplasm was assessed for resistance to corky ringspot disease (CRS) incited by transmission of tobacco rattle virus TRV. TRV is transmitted by the stubby root nematode, Paratrichodorus allius, in the Pacific Northwest, and characterized by necrotic areas in the tuber. Four tests were conducted at two different problem fields in Umatilla, OR and Pasco, WA. The fields differed in the virulence of the virus isolates. Some clones and named varieties showed resistance only in the field with the relatively mild Umatilla isolate, while others remained symptomless at both sites. The host suitability of test potatoes to three P. allius populations from the region was determined in greenhouse pot tests, and expressed as reproductive values. The Rf values for the nematodes were not correlated with resistance ratings based on visual scoring of CRS symptoms in field grown potatoes. Thus, it appears that CRS resistance is based on reaction of potato genotypes to virus and not the vector. The availability of resistant clones in in vitro form is indicated.