Ajuste e parametrização do modelo Wang-Engel para estimativa dos estádios fenológicos em genótipos de trigo

Abstract

Simulations of wheat development and growth are important tools in management decisions, agricultural planning and intensification of farming systems. The air temperature and the photoperiod are meteorological elements that influence the growth and development of wheat, being fundamental in the simulations of plant development. The objective of the work was to adjust and parameterize the phenological model proposed by Wang and Engel (WE) to predict wheat phenology. The WE model simulates the development of the plant considering the non-linear effects of the average daily air temperature and the photoperiod, being the same multiplicative. The phytotechnical and agrometeorological information was obtained by the Agrometeorology sector of the ABC Foundation, in the 2007 to 2017 harvests, for different locations in the state of Paraná and one in São Paulo, obtained for the genotypes Quartzo, Supera and Sinuelo. The phenological stages of wheat were evaluated weekly according to the Zadoks scale, for the simulation of phenology. The database totaled 1248 observations, 904 (72.4%) of which were used in the calibration and 344 (27.6%) independent observations to validate the adjusted WE model. The estimated phenologies were compared to those observed, through simple linear regression analysis, the root of the mean square error (RMSE), determination coefficient (R2), agreement index (d) and performance index (c). The adjustment of the WE model by the addition of the phenological stages simulated with excellent performance, obtaining index “d” and “c” with values greater than 0.95. The genotypes present statistically significant differences in the model's coefficients, using Student's t test p <0.05. The RMSE with the adjusted WE model was 4.48 days for Quartzo, 3.67 days for Supera and 3.64 days for Sinuelo, considering all stages of development. The calibrated and validated phenological model using 152 cultivation environments, three genotypes and five locations, demonstrates accuracy and precision in the prediction of the phenological stages of wheat for the region of Campos Gerais and the south of the state of São Paulo. It was found that the model has potential for use in other genotypes, as observed for the Toruk genotype.