Determining a model to estimate leaf area in Pornunça (Manihot sp.) using morphometric measures

ABSTRACT. Pornunça is a species of the genus Manihot that has been cultivated as an option for animal feeding in the Brazilian semi-arid. Leaf area (LA) is important to determine forage plant growth, whose evaluation model has to meet the following characteristics: practicality, precision and low cost. The objective of this study was to set a model to determine the leaf area in Pornunça (Manihot sp.) from morphometric measurements of the leaf. The experimental design was in randomized blocks with three methods for determination of leaf area, and three blocks, with 144 replicates (leaves). For the determination of LA, the direct method (FAReal), treadmill leaf area meter (Li-Color 3100©) and linear dimensions were used. Data were subjected to regression analysis. There was a relationship between the actual leaf area (FAReal) for small, medium, large and total leaves, and the leaf area determined by the treadmill leaf area meter (FALi-Cor©) with a high coefficient of determination for linear fit. The Pornunça leaf area obtained by the Li-Cor3100© meter is approximately 10% lower compared to the FAReal method. The model that best fit the Ponunça leaf area estimation was the potential.