TROCAS GASOSAS DE CAFEEIROS EM DIFERENTES ESTÁGIOS FENOLÓGICOS

Abstract

Areas of the Cerrado of Goiás have few studies on arabica coffee, especially on its physiological behavior, which is crucial for the selection of materials adapted to adverse conditions. In all there are 132 cultivars registered in MAPA, thus causing doubts to the producer about the best material for his region. Knowing this, the objective was to evaluate gas exchange of three coffee cultivars in their third crop, during the phenological cycle, at three times of the day, under the edaphoclimatic conditions of Ceres-GO. The experiment was in sub-divided plot, with 10 phenological stages (Floral Induction, Flowering, Chumbinho, Expansion I, Expansion II, Granation I, Granation II, Granation / Maturation, Maturation and Postharvest), three times (9, 12 and 15 hours) and three genotypes (Obatã Vermelho IAC 1669-20, Paraíso MG 419-1 and IBC-Palma II), which were selected taking into consideration the yield of the previous crop, the highest, medium and smallest. The variables consisted of net photosynthetic rate (µmol.m-2.s-1) and sweating (µmol.m-2.s-1). CO2 input (ppm), leaf temperature, air temperature and radiation were monitored. Data were submitted to ANOVA, compared by Tukey test at 5% probability. Gas exchange had the highest activity at 9 o'clock for all phenological stages and cultivars studied. The stages of granation and maturation performed the highest photosynthetic rate for the three cultivars at the three times of the day