Proposition of empirical equations to describe the kinetics of water absorption by film-coated maize seeds during germination

Abstract

Maize is a crop widespread in various parts of the world, serving as a source of food for humans and animals and also as a source of energy. Seeds can be attacked by pathogenic microorganisms and, a way to protect them against these attacks, it is to coat them with suitable products. In this paper, empirical equations with 2 and 3 parameters are proposed to describe the kinetics of water absorption by film-coated maize seeds during germination at temperature of 10 °C and atmospheric pressure of 71 cmHg. A total of 14 experiments involving different types of film on the seeds were carried out, plus a control experiment without film coating. A computer program, which automatically fits about 200 functions available in its library to the experimental data, was used for each of the 15 datasets. This program uses non-linear regression to generate a classification of the best-fitted functions, based on the value of the reduced chi-square of each fit performed. The best equations with 2 and 3 parameters obtained in this study were compared with each other, and the one that best described the kinetics of water absorption by the seeds was chosen. Also, the equation chosen in this study was compared with other empirical equations available in the literature. In all comparisons, the equation obtained and proposed in this study showed better statistical indicators than the empirical equations available in the literature. It was also possible to conclude that the film coating treatments did not significantly interfere with the value of the final moisture content (about 35%, w.b.), but influenced the time of the seed germination process (between 24 and 40 days).