Response of Blackberry Cultivars to Nematode Transmission of Tobacco Ringspot Virus

A study was conducted on eight cultivars of blackberry (\u27Apache\u27, \u27Arapaho\u27, \u27Chester\u27, \u27Chickasaw\u27, \u27Kiowa\u27, \u27Navaho\u27, \u27Shawnee\u27, and \u27Triple Crown\u27), of which four plants of each were previously determined in the fall of 2001 to have root, but not leaf, infection with Tobacco ringspot virus (TRSV). The objective of our study was to determine virus effects on plant vigor, and the spread of virus infection in the plants. Eight plants of each cultivar, four infected and four free of infection, were grown in pots on a gravel pad for the 2002 growing season, and samples of primocane and floricane leaves were taken to determine if TRSV had moved to the above-ground portion of the plants. TRSV injection was determined by ELISA tests. At the end of the growing season (October), the plants were harvested and dry weights determined for floricanes, primocanes, and roots to determine virus effects on plant vigor. In all plants that had been shown to have root TRSV injection, the virus was shown to have moved into the top portion of the plants as evidenced by positive ELISA tests on primocane and floricane leaf tissue. Dry weight results indicated no significant interaction of virus infection and cultivar, or any main effects of virus on cane or root growth, as all dry weights were similar for infected and non-infected plants. No dramatic leaf symptoms of virus injection were observed on infected plants in our study at any time during the growing season. Further research should focus on possible virus effects on plants that have been injected for a longer period of time to determine if in fact the virus has any effect on plant growth or productivity