Production of 'Hamlin' orange trees budded on 'Sunki' mandarin rootstock, and monthly rainfalls at the plateau of Botucatu, Brazil

Abstract

This paper deals with the existence of empirical relationship between the production of a sweet orange orchard, planted at the plateau of Botucatu, with rainfalls that occurred before the picking season. The plants were of sweet orange 'Hamlin' variety, budded on Sunki' mandarin rootstock, planted on Terra Roxa Estruturada" soil, at an altitude of 810 m above sea level. The orchard was conducted by conventional ways and no irrigation was applied. Production showed downwards of 54% and 61% and recuperations up to 139% and 229%. The production of the crop was correlated with the age of the orchard and with rainfall totals that occurred in the sixteen months before the picking season. Regression equations envolving one or more values of rainfall were calculated. These equations could explain until 99% of orange yield variation. They showed that the yield forecast in advance could be done at the anthesis and at the fruitset.