Prediction of bud break, full bloom and harvest dates for the Goethe grapevine variety in Urussanga, SC, Brazil

Abstract

The objective of this work was to develop models to predict the different phenological stages of the Goethe grapevine variety, such as bud break, full bloom and harvest date, using air temperature data, for Urussanga-SC region, Brasil. In seven years of phenological records, the stages occurred in September, October and January, respectively. Average temperatures in the June-August quarter and in the period from 11/06 to 10/08 were the ones that had the highest correlations coefficient with the budburst date (R = -0.94 and -0.93, respectively; p <0.01). The daily average temperatures accumulated in the phases budburst-flowering and flowering-harvest did not show significant correlation (p> 0.05) with the duration of these stages. However, the total number of hours with temperatures between 19.0 and 25.0 °C in the first 14 days of the budburst-flowering stage, and the first 30 days of the flowering-harvest stage explained 83% and 64%, respectively, of the variability in the duration of these stages. Temperatures below 16.0 °C were positively correlated with the duration of phenological stages, indicating a slower plant development under this thermal limit. The results show that the duration of the phases budburst-flowering and flowering-harvest is mainly influenced by the temperatures that occur in the initial period of the stages.