Productivity and wine assessment of new disease resistant cultivars in Australia

Evaluating new grape cultivars for their performance is crucial to determine their suitability for a region, but assessing wines made from grapes from these cultivars is equally important to validate market potential. Breeding grapevine cultivars with disease resistance is a high priority, particularly resistance to the two major diseases, downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necator syn. Uncinula necator). Downy mildew requires high humidity and rainfall to germinate and grow, whereas powdery mildew develops under a wide range of climatic conditions. The drivers for breeding disease-resistant winegrape cultivars include lowering the cost of production by reducing spray applications and thus the need for labour, chemicals and fuel, improving the microbial activity of the soil in the vineyard by reducing the compaction caused by tractor usage, and to provide a healthier environment around vineyards. From the first generation crosses made by CSIRO, a total of 20 white and 20 red cultivars exhibiting promising viticultural and winemaking characteristics have been selected. These selections have been planted in diverse grape growing regions around Australia and are under evaluation. NSW DPI evaluates these selections in the Orange and Riverina regions in New South Wales (south-eastern Australia) for productivity, grape composition and wine attributes. The most comprehensive results from the white selections growing in the Riverina region showed considerable differences in yield, yield parameters and must composition. Experimental wines made from these selections showed not only a considerable range in the overall scores, but also differences in aromas and attributes. In the future these cultivars will allow reduced production costs of wines exhibiting style characteristics similar to current major cultivars.