A study was conducted viewing the establishment of a sampling method which would allow to calculate the number of fruits of an orange orchard. Based on the counting of fruits borne by 5 cm diameter branches, the study was conducted during three successive agricultural seasons. The fruits in one single 5 cm diameter branch, randomly taken from a tree, were counted and this number multiplied by the total number of trees in the orchard. Three to five, six to ten and more than 10 year old orange trees from orchards of the 'Hamlin', 'Pera', 'Natal', and 'Valência' varieties were used for the experiment. 'Natal' and 'Valência' varieties were analysed in conjunction so that the total number of treatment combinations was 9. Models of linear regression for the total number of fruits borne by a tree were adjusted as a function of the number of fruits per branch and this resulted in determination coefficients varying between 0.79 and 0.94. With the exception of the 'Hamlin' cultivar, plants of the same age range presented similar results. It was thus concluded that the sampling method here devised is economical, quick, simple and permits the estimation of the total number of fruits in an orange orchard with acceptable accuracy.
sampling; linear regression; Citrus sinensis; yield estimation
