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
