The aim of this research wAS to determine the thermal requirements in degree-days for sub-phases of fruit development in arabic cultivars and to indicate those genotypes for scalonated harvesting. This research was carried out at the experimental farm of the Agronomic Institute of Paraná (IAPAR), in Londrina, state of Paraná, Brazil. Each plant was evaluated at 15 to 20 days intervals from August 2004 to August 2005 (harvest 2004/05) and from August 2005 to August 2006 (harvest 2005/06), according to a phenological scale of fruit development. The average number of days, the thermal requirements in degree-days, the accumulated precipitation and the average temperature to reach the stadium of complete maturation (cherry) were, respectively, 226.2 ± 15.3 days, 2781 ± 143.5 degree-days, 1065 ± 149.2 mm and 22.49 ± 0.47 ºC. It was possible to characterize the genotypes by their thermal needs as follows: the cultivars Icatu Precoce IAC 3282, Mundo Novo IAC 464-12, IAPAR 59, Rume Sudam IAC1139 and Costa Rica 95 as early maturation; the cultivars Catucai 785-15, Catucaiaçu, Villa Sarchí ICAFÉ, Rubi MG1192 and Ouro Verde IAC H5010-5, as intermediate maturation; the cultivars 'Obatã IAC 1669-20', Sarchímor IAPAR88480-8, 'Tupi IAC 1669-33', 'Catuaí Vermelho IAC 99', 'Catucai vermelho 4-79' and Sarchímor E9702 III-1-9 as late maturation. By using regression analyses it was possible to determine and quantify the influence of water supply in different phenological stages. The occurrence of water deficiencies accelerated maturation, therefore, reduced the thermal necessities for fruit maturation in Arabic coffee.
Coffee; scalonated harvesting; degree-days; fruit development
