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- Relationships between nutrient composition of flowers and fruit quality in orange trees grown in calcareous soilPublication . Pestana, M.; Beja, Pedro; Correia, P. J.; Varennes, Amarilis de; Faria, E. A.A field experiment was conducted in a commercial orange orchard (Citrus sinensis (L.) Osb. cv. ‘Valencia late’ grafted on Citrange Troyer) established on a calcareous soil in the south of Portugal, to investigate if flower analysis could be used to predict fruit quality. In April 1996, during full bloom, flowers were collected from 20 trees. In March 1997 the fruits were harvested and their quality evaluated. This procedure was repeated every year during three years. Principal Component Analysis was used to evaluate the patterns of covariation in the concentrations of nutrients in flowers and in fruit quality parameters. Stepwise selection procedures wer then used to develop regression models relating fruit quality parameters to the mineral composition of flowers. The predictive power of the regression models was evaluated using an independent set of data. The mineral composition of flowers at full bloom could be used to predict quality parameters of fruit in the following year, namely fruit fresh weight and the maturation index. Magnesium, Ca and Zn registered in flowers were related to fruit fresh weight estimations and N, P, Mg and Fe were related to fruit maturation index. Reference values were determined for the mineral composition of flowers, corresponding to trees where fruits had a diameter > 76 mm.
- Relationships between nutrient composition of flowers and fruit quality in orange trees grown in calcareous soilPublication . Pestana, M; Beja, Pedro; Correia, PJ; De Varennes, A; Faria, EATo determine if flower nutrient composition can be used to predict fruit quality, a field experiment was conducted over three seasons (1996-1999) in a commercial orange orchard (Citrus sinensis (L.) Osbeck cv. 'Valencia Late', budded on Troyer citrange rootstock) established on a calcareous soil in southern Portugal. Flowers were collected from 20 trees during full bloom in April and their nutrient composition determined, and fruits were harvested the following March and their quality evaluated. Patterns of covariation in flower nutrient concentrations and in fruit quality variables were evaluated by principal component analysis. Regression models relating fruit quality variables to flower nutrient composition were developed by stepwise selection procedures. The predictive power of the regression models was evaluated with an independent data set. Nutrient composition of flowers at full bloom could be used to predict the fruit quality variables fresh fruit mass and maturation index in the following year. Magnesium, Ca and Zn concentrations measured in flowers were related to fruit fresh mass estimations and N, P, Mg and Fe concentrations were related to fruit maturation index. We also established reference values for the nutrient composition of flowers based on measurements made in trees that produced large (> 76 mm in diameter) fruit.