Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2006
Publication Date: 1/15/2007
Citation: Brown, C.R., Crosslin, J., Mojtahedi, H., James, S., Charlton, B. 2007. Stability and Nature of Resistance to Corky Ringspot Disease in an Advanced Tetraploid Breeding Population of Potato. American Journal of Potato Research. 84: 79.
Technical Abstract: CORKY ringspot (CRS) disease of potato in the Pacific Northwest of the United States is a viral disorder showing symptoms on the surface, and internally. It is caused by the tobacco rattle virus (TRV) which is transmitted by the stubby root nematode. The vector is quite common in the Columbia Basin of Washington and Oregon. However, viruliferous nematodes are rarer, infesting 5-10% of fields. Eradication of the vector appears to be impossible, and sequence of commonly adopted crop rotation may prepotentiate it. Wheat and corn preceding potato has been found to increase the incidence of CRS disease in the potato. Controlled by soil fumigation at present, the development of new cultivars with resistance is an attractive solution, if resistance is durable and does not provide viral inoculum from symptomless apparently resistant latent carriers. We present data which indicates resistance in a group of clones is stable at two distinct locations over several years of testing. Detection of TRV was attempted in symptomatic susceptible and asymptomatic “resistant” clones in tuber tissue using reverse transcriptase polymerase chain reaction (RT-PCR). TRV was rarely detected in symptomless resistant cultivars. A strong though not perfect correspondence of RT-PCR detection with occurrence of symptoms was found in susceptible materials. Therefore, resistance appears to be resistance to viral infection. These results indicate that the breeding program has successfully identified clones which are not damaged by TRV infection and which are free of virus infection, meaning they will not serve as a source of inoculum.