Study of dry matter accumulation in maize hybrids using nonlinear models

Abstract

The objective of this work was to study the growth curves of total dry matter (TDM) accumulation of the P30F33 and GNZ2004 maize hybrids using nonlinear models. The used models were: Brody, Gompertz, logistic, Meloun I, Meloun II, Michaelis-Menten, modified Michaelis-Menten, Mitscherlich, Richards, Schnute, von Bertalanffy, and Weibull. To estimate the parameters, the least squares method and the Gauss-Newton convergence algorithm were used. The adjusted coefficient of determination, the residual standard deviation, and the Akaike information criterion were used as criteria to evaluate the goodness of fit of the models. The Gauss-Newton method did not converge for 8 out of the 12 models studied. The Gompertz, logistic, von Bertalanffy, and Weibull models were considered appropriate for fitting the dry matter accumulation of the evaluated maize hybrids. The estimated TDM was 34,700 and 31,980 kg ha^-1 for GNZ2004 and P30F33, respectively. The maximum daily gain in TDM was 483 and 381 kg ha^-1, respectively, reached at 83 days after emergence, with TDM stabilization at 121 and 129 days after emergence. The logistic model is the best one to describe the TDM accumulation of the GNZ2004 and P30F33 maize hybrids.