This paper had as its purpose the determination of the inferior base temperature - Tb, and superior - TB, for arabic coffee plants. The cultivars "Acaiá Cerrado" (Mg-1474) and "Rubi" (Mg-1192) were evaluated, associating crop coefficients - Kc, to growing degrees-day - GDD. The trial was carried out in the "Universidade Federal de Lavras" - UFLA, from March 2003 to September 2004. For statistical analysis, a study with regression and comparisons among regressions using the procedure described in Snedecor & Cochran (1989) were used. The values of GDD were obtained with the methodology presented by Ometto (1981), and were compared to the methods presented by Arnold (1959), Snyder (1985) and Dufault (1997); Tb = 12.9 °C and TB = 32.4 °C were obtained after comparisons among the methods: least standard deviation in degrees-day and days, coefficient of variation in degrees-day, regression coefficient and analysis of Kc versus GDD were found. For both cultivars, up to 4200 GDD, values of 0.20, 0.89 and 0.48 were found, for Kc minimum, maximum and mean, respectively.
irrigated coffee; irrigation management; climate
