Phenology and thermal requirements of disease-resistant genotypes (PIWI) grown in the Goethe Grape Valley region of Brazil
The Goethe Grape Valley (GGV) is a traditional southern Brazilian region for grape and wine production, mainly planted with hybrid vines. High temperatures and rainfall conditions hamper the cultivation of Vitis vinifera cultivars susceptible to disease, especially Plasmopara viticola. New PIWI (from the German word Pilzwiderstandsfähige) genotypes of V. vinifera with resistance to P. viticola are under evaluation in this region. The aim of this work was to characterize the phenology and thermal requirements of PIWI genotypes grown in the GGV. The experiment was carried out in an experimental vineyard (28°32S 49°19W, altitude 60 m a.s.l.), established in 2016, and evaluations were done for the 2018 vintage. The evaluated PIWI cultivars were Aromera, Baron, Calardis blanc and Felicia. Minimum and maximum air temperatures were recorded daily, using 10°C as the low temperature threshold, 25°C as the optimum temperature for development, and 35°C as the upper temperature threshold of development. The evaluated phenological stages were budbreak to flowering, flowering to veraison and veraison to maturity. The total thermal requirement mean was 1360°C day; Felicia showed the lowest thermal requirement (1260°C day), which contrasted with Aromera, which presented the highest thermal requirement (1454°C day). Baron and Calardis blanc needed 1337 and 1391°C day, respectively, to reach maturity. From budbreak to flowering, the average thermal requirement was 229°C day, from flowering to veraison the mean was 679°C day, and from veraison to maturity the mean was 452°C day. The four evaluated cultivars exhibited adaptive development in the field with thermal requirements compatible with the region of GGV. The results also revealed the lower thermal requirement, and consequently shorter cycle, for Felicia, as well as the greater thermal requirement of Aromera.
Stefanini, M., Tomazetti, T.C., Rossarolla, M.D., Costa, A., Dela Bruna, E., Malinovski, L.I., Silva, A.L., Nodari, R.O. and Guerra, M.P. (2019). Phenology and thermal requirements of disease-resistant genotypes (PIWI) grown in the Goethe Grape Valley region of Brazil. Acta Hortic. 1248, 141-148
Vitis vinifera L., Plasmopara viticola, downy mildew, PIWI cultivars, adaptation