The objective of this research was to model and identify the best models to estimate the leaf area of pigeonpea determined by digital photos with the length or width and/or the product length width of the central leaflet limb of the leaf. Two trials were carried with the culture of pigeonpea. In the first experiment, samples from 200 leaves were taken at 45, 52, 59, 65, 72, 79, 86, 94, 100, 106 and 114 days after emergence (DAE), totaling 2,200 leaves. In the second experiment, a sample from 220 leaves was collected at 69 DAE. In these 2,420 leaves, were measured the length (CFC) and width (LFC) and calculated the product length width (CFC×LFC) of the central leaflet. Then, was determined the leaf area of each leaf (sum the leaf area of the leaflets left, center and right) by the method of digital photos (Y). After, were separated, randomly, 90% of the leaves from the first experiment (1,980 leaves), to build models of quadratic type, potency and linear for Y function of the CFC, LFC and/or CFC×LFC. The remaining 10% of the leaves from the first experiment (220 leaves) and the 220 leaves collected in the second experiment, separately, were used to validate the models. In pigeonpea, the quadratic model (Ŷ=0.4295+1.5895x+0.0011x2, R2=0.9710), the potency model (Ŷ=1.6591x0.9983, R2=0.9769) and the linear model (Ŷ=-1.3555+1.6858x, R2=0.9708), of Y as a function of CFC×LFC are adequate for estimation of the leaf area and linear, may preferably be used.
Cajanus cajan (L.) Millsp.; digital photos; modeling; non-destructive method.
