ABSTRACT
The objective of this study was to determine the harvest period of coffee fruits based on the relationship between agrometeorological parameters and sucrose accumulation in the seeds. Over the crop years 2004/2005 and 2006/2007, from 150 days after flowering (DAF) onwards, samples of 50 fruits of cultivars Mundo Novo IAC 376-4, Obatã IAC 1669-20 and Catuaí Vermelho IAC 144 were collected from coffee trees located in Campinas, Brazil. The endosperm of the fruits was freeze-dried, ground and analyzed for sucrose content by high-performance liquid chromatography. A weather station provided data to calculate the accumulated growing degree-day (GDD) units, and the reference (ET(o)) and actual (ET(r)) evapotranspiration rates. The results showed that the highest rates of sucrose accumulation occurred at the transition from the cane-green to the cherry phenological stage. Models for the estimation of sucrose content during maturation based on meteorological variables exhibited similar or better performance than the DAF variable, with better results for the variables GDD and ET(o). The Mundo Novo cultivar reached the highest sucrose level in the endosperm after 2,790 GDD, while cultivar Catuaí attained its maximum sucrose concentration after the accumulated evapotranspiration rate has reached a value of 870 mm. As for cultivar Obatã, the maximum sucrose concentration was predicted with the same degree of accuracy using any of the parameters investigated. For the Obatã cultivar, the values of the variables calculated for the maximum sucrose concentration to be reached were 249 DAF, 3,090 GDD, 1,020 ET(o) and 900 ET(r).
Subject(s)
Coffea/chemistry , Fruit/chemistry , Models, Theoretical , Sucrose/analysis , Climate , Coffea/physiology , Fruit/physiology , Plant TranspirationABSTRACT
Foram determinados para o café arábica cv. Mundo Novo, a temperatura base inferior e a soma térmica, expressa em grausdia, além do acúmulo de evapotranspiração de referência (ETo) e real (ETr), para o subperíodo florescimento-colheita, utilizando-se dados fenológicos de cultivos dos anos de 1971 a 2004. Foi proposto ainda um fator de correção para o cálculo de graus-dia em função da disponibilidade hídrica nos oito primeiros decêndios após o florescimento. Os valores de temperatura-base e soma térmica obtidos foram de 10,2ºC e 2887 graus-dia e 10,5ºC e 2761 graus-dia, quando determinados sem e com correção pelo fator hídrico, respectivamente. O acúmulo médio de Eto para o subperíodo do florescimento à colheita foi de 761mm e para Etr 689 mm; quando se levou em consideração o acúmulo de ETr apenas no início do desenvolvimento dos frutos (oito primeiros decêndios), o valor médio foi de 721mm. A utilização de métodos que levaram em consideração a influência da disponibilidade hídrica melhorou a estimativa da temperatura base e a soma térmica no subperíodo do florescimento à colheita do cafeeiro Mundo Novo.
Base temperature and heat requirement, using degree-days were evaluated for coffee cv. Mundo Novo. The sum of reference (ETo) and actual (ETr) evapotranspiration were also determined for the flowering-harvest phenological stage, using coffee phenological data for the growing season from 1971 to 2004. A correction factor was proposed for the degree-days sum related to available water on the first eighty days during the beginning of flowering. The obtained values of base temperature and degree-days requirements were, respectively, 10.2ºC and 2887 degree-days and 10.5ºC and 2761 degree-days when evaluated with and without adjustement for water deficit. The mean value for ETo sum was 761 mm, and for ETr, 689 mm. When considered the sum of ETr during the development of the berries (first 80 days after flowering) was considered the mean values were 721 mm. The correction factor for water deficit improved the determination of base temperature and heat sum for the flowering-harvest stage for Mundo Novo coffee plants.
