Evaluating the 2nd generation of disease resistant winegrape varieties

This project will assess the viticultural performance of ~500 2nd gen mildew-resistant varieties in Griffith and Orange and the wine sensory characteristics over at least 2 seasons of fruit produced in Griffith. Those 2nd gen varieties showing the most potential would then be selected for planting in replicated trials in unsprayed vineyards in Griffith and Orange for further evaluation of viticultural performance, fruit characteristics and wine sensory leading to commercial release. No premium winegrape varieties used for the production of Australian wine have any significant resistance to the major pathogens powdery mildew or downy mildew. As a result, grape growers are totally dependent on the frequent application of fungicides to control these diseases. A previous Wine Australia project (CSP 0904) resulted in the breeding and selection of new 1st gen mildew-resistant varieties through introgression of the Run1/Rpv1 locus from the North American species Muscadinia rotundifolia, which confers strong resistance to powdery and downy mildew. These selections were planted in replicated trials in Irymple, Wagga Wagga and Orange to assess vineyard performance and wine quality/style (CSP 1303 & CSA 1701-1.6) and a number of these 1st gen. selections are now under evaluation by growers and wine companies. In Wine Australia project (CSA 1701-1.1) the Run1/Rpv1 locus was successfully combined with a new powdery mildew/downy mildew resistance locus (Ren4/Rpvrom) from the Chinese species V. romanetii using marker-assisted selection to produce 2nd gen mildew-resistant varieties. In addition, the red-flesh locus from the grape variety Dunkelfelder has been introgressed into some of the red selections to produce varieties that not only have durable mildew resistance but also have elevated levels of anthocyanin production to address the challenge of producing red wines with acceptable colour under increasing temperatures caused by climate change. Over 600 2nd gen. red and white progeny have been established in an unsprayed block at SARDI research station at Nuriootpa.