Delimitation of Agro-climatic aptitude for vine crop under irrigation in the Northeast Brazil

Long term weather data were used together with simple regression models involving crop coefficient (Kc), reference evapotranspiration (ET0) and accumulated degree days (DDac) to quantify the vineyard water requirement (VWR) of table and wine grapes in the Brazilian Northeast. VWR joined with precipitation, allowed the development of a vineyard water indicator (VWI), which was applied together with average values of air temperature for a growing season to characterize the agro-climatic aptitude. For table grapes it was observed that the region has no thermal limitation, however higher both sugar contents and grape yield would be obtained in the areas with higher values of air temperature. In relation to wine grape, it was observed that there are some thermal limitations for the wine quality, depending on the pruning date, being higher the alcohol content and lower acidity, in wines elaborated under conditions with higher values of air temperature. In relation to table grapes, the best pruning dates are between June and September, being highlighted the west areas of Bahia, Pernambuco, Paraiba and almost all areas of Rio Grande do Norte, Ceara, Piaui and Maranhao. Considering wine grapes, the best agro-climatic aptitude is for pruning dates from May to June, with highlights for the states of Bahia, Pernambuco, Paraiba, Alagoas and Sergipe, and a southeast area of Maranhao state.