Field performance of five white Pilzwiderstandsfahige (PIWI) cultivars in the south of Brazil

Southern Brazil is the largest grape-producing region in the country. It is characterized by the production of labrusca grapes, because of the difficulty of growing Vitis vinifera. This can be explained by the high occurrence of fungal diseases, especially downy mildew, which is favored by the environmental conditions (high temperatures, relative humidity and rainfall). Pilzwiderstandsfahige (PIWI) are a group of wine-grape cultivars similar to V. vinifera but with resistance to downy and powdery mildew. These cultivars open the possibility of reducing production cost and agrochemical sprays for viticulture in Brazil. In order to achieve this objective, studies related to phenological, productive and qualitative characteristics are necessary. A PIWI cultivar trial was established in 2015, in the city of Videira, Santa Catarina State, Brazil, with five white cultivars. The vines were trained in vertical shoot position (VSP) trellis and pruned in double cordons. The studied cultivars were 'Felicia', 'Calardis Blanc', 'Helios', 'Bronner' and 'Aromera', grafted on 'Paulsen 1103'. The variables evaluated were phenology, incidence of downy mildew, yield, number of clusters, average cluster weight, total soluble solids, pH and total titratable acidity. In terms of productivity, the outstanding cultivars were 'Felicia' and 'Calardis Blanc', with yields above the traditional V. vinifera cultivars. 'Felicia' was the earliest cultivar and produced the heaviest clusters. 'Calardis Blanc' presented the largest number of clusters, and 'Aromera' was the latest cultivar. Soluble solids contents, pH and acidity were adequate in all cultivars. In general, all tested cultivars showed good potential for the studied region.