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Leaf area estimation in Coffea canephora genotypes by neural networks and multiple regression 1 1 Research developed at Universidade Federal do Espírito Santo, São Mateus, ES, Brazil

Estimativa da área foliar de genótipos de Coffea canephora por meio de redes neurais e regressão múltipla

ABSTRACT

Leaf area data from coffee plants are important for studies and analyses of grain yield, physiology, adaptation to environmental conditions, and cultural management. The objective of this study was to predict leaf area of coffee plants using artificial neural networks and compare the efficiency of this methodology with multiple regression models. Forty-three genotypes of similar reproduction and age were evaluated, testing 14 types of multiple regression equations from combinations of leaf length and width. The backpropagation algorithm was used to develop multilayer perceptron neural networks; several combinations were tested between two activation functions of the intermediate layer (hidden layer) and the number of neurons in this layer. The best fitting results in the artificial neural network modeling were found with the sigmoid activation function and three neurons in the hidden layer (R² = 0.990 and RMSE = 2.855 in the training phase). Considering the errors (RMSE, MAE, and MAPE) and the coefficient of determination as criteria for best fit, the artificial neural network models better estimated the leaf area in the training and validation phases. Therefore, the artificial neural network methodology can be used as alternative for estimating leaf area of coffee plants.

Key words:
statistical models; artificial intelligence; backpropagation; leaf length and width

HIGHLIGHTS:

Backpropagation neural networks can be used to estimate leaf area of Coffea caneph-ora.

The use of non-destructive methods is a viable alternative for determining leaf area of C. canephora.

Multiple regression can be replaced by artificial neural network models for estimating leaf area.

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