Utilizacion de parametros de calidad de jugo para determinar tiempo optimo de cosecha en variedades de naranjas 'Hamlin' y 'Rhode Red Valencia'

Optimum time of harvest of oranges (Citrus sinensis [L.] Osbeck) varies depending on variety and environmental conditions. Physicochemical qualities of the fruit and juice are related to fruit maturation. A study was conducted to determine the optimum harvest time of varieties 'Hamlin' and 'Rhode Red Valencia' grafted onto mandarin 'Cleopatra' and citrumelo 'Swingle' rootstock planted in Adjuntas, Corozal and Isabela, Puerto Rico. Fruit weight and diameter, juice percentage, peel and internal color, pH, total acidity (AT), total soluble solids (TSS), maturity index (TSS/TA), citric and ascorbic acid were determined in fruits sampled at four harvest dates (September to December for 'Hamlin' and February to May for 'Rhode Red Valencia').;Fruit of 'Hamlin' averaged 170 g while fruits of 'Rhode Red Valencia' averaged 236 g. Percent juice were greater than 43% in 'Hamlin' and greater than 52% in 'Rhode Red Valencia'. Acidity averaged 0.72% and 0.79% in 'Hamlin' and 'Rhode Red Valencia', respectively. TSS averaged 8.17 in 'Hamlin' and 10.4 in 'Rhode Red Valencia'. The maturity index (TSS/TA) for 'Hamlin' was 12.9 and 14.2 for "Rhode Red Valencia'. These values were used to determine optimum harvest times by considering which months had the largest number of parameters at an acceptable level.;The optimum harvest time for 'Hamlin' was September to October in Isabela and November to December in Adjuntas and Corozal. Fruits of 'Rhode Red Valencia' should be harvested in February to March in Isabela and April to May in Adjuntas and Corozal.