Statistical models to describe the fruit growth pattern in sweet orange 'Valencia late'

Abstract

The objective of the present work was to find the statistical model that best describes the pattern of fruit growth of sweet orange 'Valencia late' in the departments of Concepción (orchard 1) and General Paz (orchard 2), province of Corrientes, Argentina. In order to fit the growth curves, models of sigmoid type: Logistic, Gompertz, Weibull, Morgan Mercer Flodin, Richards, and reparameterizations of the Logistic and Gompertz models, were evaluated and compared. As criteria for selecting the model, measures of nonlinearity and estimates of residual variance for the different models and reparameterizations were compared. The model found to be most suitable to describe 'Valencia late' orange fruit growth was the fifth parameterization of Logistic model: y = 1/α + exp(β)γx . In this model, β and γ had similar values on all fruit sizes in orchard 1, but different values for fruit sizes in orchard 2; α values varied for both orchards between fruit sizes. For this reason, a family of curves will be necessary for different situations.