Estimação dos pontos críticos do crescimento de frutos de café conilon: intervalos de confiança via bootstrap

Abstract

Conilon coffee (Coffea canephora) is an agricultural crop of great economic importance, especially in tropical regions, due to its resistance to adverse conditions and its strategic role in national production. In this context, an in-depth understanding of fruit growth and development is essential to improve management practices, increase productivity, and ensure the quality of the final product. Therefore, this study aimed to describe the dry matter accumulation in conilon coffee fruits using the Logistic model for clones P1, 204, and 407, with emphasis on the estimation of critical points of the growth curves and their respective confidence intervals. The data used were obtained from the study by Senra et al. (2022). The estimation of the critical points and the roots of the model’s derivatives was carried out using the Newton–Raphson method, while the confidence intervals for these points were estimated using the bootstrap resampling technique. The quality of model fit was evaluated using the coefficient of determination (R 2 ). The estimated values for parameter b, which represents the moment of maximum dry matter accumulation, were 117, 84, and 59 days after flowering for clones P1, 204, and 407, respectively, with corresponding maximum dry masses (parameter a) of 21.66 g, 21.12 g, and 14.53 g. These results support the classification of the clones in terms of fruit development as late (P1), intermediate (204), and early (407). Among the critical points, noteworthy are the estimated values for the point of maximum deceleration (PDM), obtained at 198, 160, and 125 days after flowering, and for the point of asymptotic deceleration (PDA), at 259, 216, and 174 days, respectively. This differentiation in growth cycles is particularly relevant for planning management practices and harvest scheduling. The characterization of these critical points contributes to strategies for efficient input use and maximization of productive potential. Moreover, the interval between the PDM and PDA defines the ideal physiological stage for the application of ripening agents, promoting maturation uniformity and optimizing harvesting. Thus, the results obtained strengthen the scientific foundation for more efficient and sustainable conilon coffee management.