Submitted to: Archives of Phytopathology and Plant Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/10/2007
Publication Date: 1/1/2007
Citation: Olanya, O.M., Reeves, A.F., Lambert, D.H., Porter, G.A. 2007. Evaluation of potato breeding lines for resistance to stem canker and tuber black scurf in field studies following artificial inoculation with rhizoctonia solani ag-3 in maine. Archives of Phytopathology and Plant Protection. 2007 On Line. p. 1-10. 2009 42:409-418. Interpretive Summary: Rhizoctonia stem canker is an important disease on potato seedlings when wet conditions are prevalent. In recent years, stem canker and black scurf have become an increasingly significant disease in Maine. Resistance and susceptibility of potato breeding lines and varieties to stem canker and tuber black scurf were evaluated under field conditions after artificial inoculation with the fungus. Seedling emergence and disease components were quantified. Several potato breeding lines were identified as moderately resistant to stem and root canker. The use of breeding lines in addition to other management components can be effective for disease management under conditions specific to Maine.
Technical Abstract: Resistance and susceptibility of potato breeding lines to Rhizoctonia stem canker, root lesion numbers and black scurf was evaluated in field experiments during 1997 and 1998 growing seasons. In a randomized complete block design with four replications, potato lines were inoculated with Rhizoctonia solani Anastomosis group 3 (AG-3) by dipping seed pieces in a slurry or suspension of inoculum and planted. A control treatment in which the seed pieces were not inoculated was also planted. At two weeks after planting, effects of seed piece inoculation on seedling emergence was assessed for a period of five weeks. After 90 days of plant growth, assessments for the incidence and severity (%) of Rhizoctonia stem and stolon cankers was conducted. Similarly, the number of root and stolon lesions were also quantified. At harvest, incidence of black scurf on tubers and effects of fungal inoculation on tuber size distribution and yield were also determined. Average emergence of potato seedlings (%) was similar between the inoculated and non-inoculated treatments, however the rate was different. Differences in the resistance of potato lines to stem and root cankers were detected in both years. No significant differences in the susceptibility of potato lines to black scurf (sclerotia on tuber surface) were observed. Incidence and severity of stem cankers and the numbers of stem and root lesions were not significantly correlated with the incidence of black scurf on tubers.