Validation of the PhenoGlad model and determination of planting dates of the gladiolo for the state of Paraná

Abstract

Mathematical models that simulate crop development are important tools to help growers plan management practices and harvest time for cut flowers such as gladiolus. The objective of this work was to validate the PhenoGlad model for the State of Paraná, determining the planting date for marketing flowers for the Day of the Dead, and the quality of the floral stems. The validation of the PhenoGlad model was carried out through field tests in five towns in the State of Paraná, namely: Cascavel, Dois Vizinhos, Marechal Cândido Rondon, Palotina, and Santa Helena. The experiments were carried out during the year 2019. The PhenoGlad model was run for each location and year of meteorological data for the early, The PhenoGlad model was simulated for each location and period of meteorological data available at each weather station in these towns, and for the early, intermediate II, and late development cycles. The planting date was determined through the average of the dates (Julian days) for each simulated year. The variables analyzed were the stages of development according to the phenological scale of the culture, the number of leaves, the average number of florets, and the classification of floral stems according to the quality standards of Veilling Holambra. The PhenoGlad model showed accuracy in simulating the stages of development of gladiolus culture in the state of Paraná and is also suitable for predicting the damage caused by extreme temperatures in floral stems, which was confirmed by the damage caused to sepals and petals of gladiolus in field experiments in the towns of Cascavel, Dois Vizinhos, Palotina, and Santa Helena. The best model performance was observed when simulating the vegetative period of the crop, presenting a low error of 0.54 leaf. In the state of Paraná, for the production of floral stems for the Day of the Dead, the PhenoGlad model simulated the planting dates in the different towns studied from August 1 to August 23. The towns of Cascavel and Marechal Cândido Rondon presented a higher number of florets and higher quality of floral stems than the other towns evaluated.