Comparison of heat-unit methods to predict tomato anthesis Comparación de métodos que utilizan unidades de calor para predecir la antesis de tomate

The aim of this work was to compare methods to predict the time of anthesis in tomato (Solanum lycopersicum L.). Two independent experiments were carried out using seeds of the Tauro commercial hybrid. Daily maximum and minimum air temperatures were measured by means of an electronic thermometer with data storage; the photoperiod was calculated using a mathematical procedure. The moment at which each inflorescence presented 50% of its flowers in anthesis was recorded. The use of calendar days (CD) had a high dispersion, which was measured with a variation coefficient (VC) higher than 3.70% for all inflorescences. The method that considered both a base temperature and the photoperiod allowed the highest prediction uniformity for the conditions of this assay, since its VC was lower than 0.30%.