Modelos de desenvolvimento e temperaturas cardinais de cultivares de videiras viníferas

Abstract

The vine growing is used in many regions of the world, however, there are few areas suitable for producing fine wines. The Fronteira Oeste do Rio Grande do Sul having the climate conditions favorable to the development of grape vines, however, it is necessary to study the development of the culture in this region. Due to this, the objective with this work was to define the cardinal temperatures for developing vines grapes grown in the region Fronteira Oeste do Rio Grande do Sul and the thermal time required to complete the production cycle. The phenological development of the vines „Cabernet Sauvignon‟, „Tannat‟, „Ruby Cabernet‟, „Merlot‟ e „Chardonnay‟ was accompanied in the growing seasons 2005/06 to 2009/10, the minimum and maximum air temperature were collected daily and used to obtain the average temperature. Were tested eight methods of thermal sum daily, considering the lower base temperature in the methods 1.1; 1.2 and 1.3, lower base temperature and optimum in the methods 2.1 and 2.2, lower base temperature, optimum and base higher in the methods 3.1; 3.2 and 3.3, the methods were compared using the standard error (SE), root mean esquare error (RMSE) and coefficient of variation (CV%), recital 10 °C, 25 °C and 38 °C for the lower base temperature, optimum higher base respectively. The best estimation method was used to determine the cardinal temperature, was first defined the lower base temperature, followed by optimum temperature and higher base temperature, to individual varieties. Using determined cardinal temperatures, was obtained the thermal time daily and thermal time accumulated along of the crop cycle, the methods tested were again compared by the statistical above. The method 3.3 showed the smallest deviations, proven to be suitable for calibrating the cardinal temperatures of varieties, the lower base temperature were 7,7; 6,4; 6,1; 6,8 e 5,7 °C respectively for „Cabernet Sauvignon‟, „Tannat‟, „Ruby Cabernet‟, „Merlot‟ e „Chardonnay‟. The optimum temperatures were 26,7; 22,9; 22,9; 22,7 e 22,8 °C respectively for „Cabernet Sauvignon‟, „Tannat‟, „Ruby Cabernet‟, „Merlot‟ e „Chardonnay‟. The temperature higher base obtained were 38,7; 43,6; 47,0; 43,3 e 37,2 °C respectively for „Cabernet Sauvignon‟, „Tannat‟, „Ruby Cabernet‟, „Merlot‟ e „Chardonnay‟. The method 3.3 adjusted better to „Cabernet Sauvignon‟, „Merlot‟ e „Chardonnay‟ with CV 8,21%, SE 97,52 °C day and RMSE 218,07 °C day for „Cabernet Sauvignon‟, CV 7,81%, SE 71,33 °C day and RMSE 159,49 °C day for „Merlot‟ and, CV 11,19%, SE 91,41 °C day and RMSE 204,40 °C day for „Chardonnay‟, the method 3.1 showed better adjustment for „Tannat‟ and „Ruby Cabernet‟, with CV 2,00%, SE 19,76 °C day and RMSE 44,18 °C day and, CV 8,68%, SE 94,72 °C day and RMSE 211,80 °C day, respectively. We conclude that the cardinal temperature vary with the varieties, is suggested to use the method 3.3 for simulation the thermal time daily in development studies grapes vines.