Performance of resistant grape varieties (PIWI), 'Felicia', 'Calardis Blanc' and 'Helios' in two locations of Santa Catarina State (BR)

Downy mildew (Plamopora viticola) is one of the major problems to produce wine grapes in Brazil, a main cause of yield losses in the Southern region of the country. An alternative to the use of pesticides is the use of resistant varieties (PIWI): wine grapes combining high oenological potential and resistance to diseases. The goal of this work was to assess the vegetative and productive performance and maturation of three PIWI varieties ('Felicia', 'Calardis Blanc' and 'Helios') produced at altitudes of 840m and 1250m in the 2020, 2021 and 2022 vintages. The study is focused on four phenological stages: budbreak (BBCH 7), full bloom (BBCH 65), veraison (BBCH 81) and maturity/harvest (BBCH 89). The criteria for measuring the productive performance were, the number of clusters, average cluster weight, production per plant, yield and Ravaz index. As parameters for technological and phenolic maturation, pH, soluble solids, total acidity and total polyphenols were evaluated. The budbreak occurred at the end of August until the second fortnight of September, the flowering occurred in the second week of October, the veraison occurred during the month of December, and the maturity/harvest occurred from the second fortnight of January until the beginning of February. The earliest bud break occurred with 'Felicia' in the vineyard at 1250m and the latest occurred with 'Calardis Blanc'. Regardless of the vineyard altitude, there was practically no difference in the flowering date between varieties and the vineyards altitude, the veraison and the maturity/harvest occurred earlier in the vineyard at 840m. The varieties produced at 840 m had a shorter cycle and proved to be more productive when compared to those produced at 1250 m. The studied varieties showed good phenological adaptation, high yield and maturation indices suitable for the production of quality still and sparkling white wines at both altitudes. From the results obtained, 'Felicia' and 'Calardis Blanc' seem to be the most promising varieties for cultivation in both altitude ranges.