Date of Graduation

Spring 2017

Degree

Masters in Plant Science

Department

College of Agriculture

Committee Chair

Wenping Qiu

Keywords

‘Norton’, ‘Cabernet Sauvignon’, new variety, GVCV, grape, virus, Vitis

Subject Categories

Agriculture | Biotechnology | Viticulture and Oenology

Abstract

One of the most effective methods of reducing pesticide application in vineyards is breeding hybrid varieties for disease resistance. The new varieties must be assessed for disease resistance and viticultural traits. This thesis focuses on seven new varieties from a cross of ‘Norton’ and ‘Cabernet Sauvignon’. ‘Norton’ was chosen because of its disease resistance and cold hardiness. ‘Cabernet Sauvignon’ was selected because of its high-quality wine making berries. The cross was made in 2005, seven were selected in 2011, and evaluation began in 2016. Using Botrytis cinerea as a model pathogen, resistance was measured with an incidence rate and severity scale. The varieties’ berry chemistry, vine vigor, and growth stages were recorded, and three have been identified as promising varieties. ‘Norton’ is resistant to Grapevine vein clearing virus (GVCV), which became a second project for this thesis. GVCV infects vineyards and causes economic losses. Two symptomatic vines, a cultivated ‘Chardonel’ and a native vine, Ampelopsis cordata, were discovered 10 feet apart along a vineyard boundary. Both samples tested positive for GVCV using a polymerase chain reaction (PCR) assay. The sequences of the two isolates share a high percentage of nucleotide identity. This suggests the same GVCV isolate infects two genera. In addition, a survey of GVCV in native Vitis plants from the National Plant Germplasm Collection was also conducted. A triplex PCR assay was developed to test 380 samples. GVCV was not found in the survey indicating the spread of GVCV is likely a localized, recent event.

Copyright

© Kaylie Austin

Open Access

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