Phenological and thermal demand (degree-days) characterization of four varieties of white grapevine cultivated in Sao Francisco River Valley, Brazil.

This was considered as a new wine making region and one of the most important in tropical zones. Where there is not enough information about phenological and thermal demand of wine grapes cultivars. The climate is unique and classified as semi-arid, where the mean total annual precipitation is 540mm, the corresponding mean pan evaporation is 2700mm and the mean annual air temperature is 26.5°C. .