Show simple item record

dc.contributor.authorSykes, Virginia Roseannaen_US
dc.date.accessioned2014-03-14T21:36:31Z
dc.date.available2014-03-14T21:36:31Z
dc.date.issued2009-04-22en_US
dc.identifier.otheretd-05212009-201102en_US
dc.identifier.urihttp://hdl.handle.net/10919/42769
dc.description.abstractBrown patch, caused by Rhizoctonia solani Kuhn, is an important disease on tall fescue (TF, Festuca arundinacea Schreb, synonym Schedonorus phoenix (Scop.) Holub). Rhizoctonia zeae Voorhees, a related pathogen, causes similar symptoms. Confusion over which Rhizoctonia species is causing symptoms and subjective visual evaluations of disease severity may contribute to variability in observed BP resistance of TF cultivars at multiple locations. The objectives of this study were to develop an objective digital image analysis (DIA) method for evaluating disease and to use DIA to screen tall fescue plant introductions (PIs) for resistance to R. solani and R. zeae. There was a strong correlation (r2 = 0.97) between actual disease severity, measured by applying lesioned tissue of a known area to healthy leaves, and DIA calculated disease severity using scanned images of individual leaves (DIA-IL). The accuracy and precision of visual evaluations and DIA evaluations of entire plants (DIA-WP) were evaluated using DIA-IL as a standard of accuracy. Accuracy of DIA-WP was not significantly different from visual evaluation accuracy. Precision was significantly higher for DIA-WP. Evaluation of PIs and putatively BP resistant TF cultivars for resistance to R. solani and R. zeae using DIA-WP identified clones within each PI that ranked high for resistance to R. solani or R. zeae. No clones were identified with high resistance to both R. solani and R. zeae. Improved precision of DIA evaluation methods and inclusion of R. zeae in BP resistance breeding may decrease variability of TF cultivar performance across locations.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartVRSYKESthesis.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectturfgrassen_US
dc.subjectdisease evaluationen_US
dc.subjecttall fescueen_US
dc.subjectbrown patchen_US
dc.subjectSchedonorus phoenixen_US
dc.titleUse of digital image analysis to identify Rhizoctonia solani and Rhizoctonia zeae resistance in Festuca arundinacea plant introductionsen_US
dc.typeThesisen_US
dc.contributor.departmentPlant Pathology, Physiology, and Weed Scienceen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplinePlant Pathology, Physiology, and Weed Scienceen_US
dc.contributor.committeechairHorvath, Brandon J.en_US
dc.contributor.committeememberAskew, Shawn D.en_US
dc.contributor.committeememberBaudoin, Antonius B. A. M.en_US
dc.contributor.committeememberGoatley, J. Michael Jr.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05212009-201102/en_US
dc.date.sdate2009-05-21en_US
dc.date.rdate2009-06-10
dc.date.adate2009-06-10en_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record