Estimates of Leaf Area of Curcubita moschata Duch. Based on Linear Measures and Degree-days in Planting of Winter in the Central-Western Region of Brazil

Abstract

Aims: Evaluate the evolution of leaf area of the pumpkin cv. Menina Brasileira Precoce by simplified estimation models based on linear measurements of the blade leaf. Study Design: Field experiment, distributed in randomized block design with four replicates of four plants each block. The sowings occurred at intervals of 10 days during the winter period to 5 planting dates (which are recommended due to the lower incidence of disease in plants), being measured 80 plants. Place and Duration of Study: Experimental Area of the Vegetal Production, University Federal of Mato Grosso, Sinop, Mato Grosso State (transition Amazon-Cerrado region), between June 2013 and December 2013. Methodology: Were obtained linear measurements (length, width and transverse) to estimate the total leaf area (LA) of plants from pumpkin cv. Menina Brasileira Precoce. The linear, polynomial and exponential simplified models to estimation of LA and the number of leaves in different size classes and position in the branches of the plant. The coefficients of the regressions were adjusted by maximizing the coefficient of determination (R²), being also employed statistical indicative MBE, RMSE, adjustment index and position value for evaluating the statistical performance of the models generated. Results: Were generated 29 simplified models estimative of LA, with R² ranging from 0.2138 to 0.7232, with maximum underestimation of 3.73 cm² and overestimation to 9.52 cm², scattering ranging from 10.46 to 17.59 cm² and adjustments above 46%. Conclusion: The leaf area of pumpkin cv. Menima Brasileira Precoce can be predicted by equation LA = 0.2720 (L + WL)1.8467 with precision, simplicity and practicality on the field cultivated.