Non–destructive leaf area determination in African eggplant (Solanum macrocarpon)

Abstract

Leaf area models are simple, accurate and non-destructive. They are important in many experimental comparisons where leaf area meters are not available. No such model exists for African eggplant (Solanum macrocarpon). This study was, therefore, conducted to develop a leaf area model for S. macrocarpon using linear measurements. A total of 80 fully opened leaves of different sizes were randomly selected. The maximum Lamina length (L) and width (W) of leaf samples were measured. Each leaf margin was traced on standard graph paper. Leaf area was subsequently estimated from the number of squares within each tracing. While the linear functions of length or width measurements, and their squares or products explained 79-92% of variations in leaf area, the linear functions of the inverse of length or width measurements, and their squares or products explained about 40-68% of the variations. Regression analysis of leaf area obtained from graph tracing as dependent variable, L and W as independent variables revealed several models that can be used for estimating the area of individual leaf. While models involving L, W, L², W², L×W, and L²×W² explained 78-91% of the variations in leaf area, models with inverse parameters (1/L, 1/W, 1/L², 1/W²,and 1/LW), explained 39-67% of the variations. Relative to all parameters evaluated, the model involving L² had the highest r², and explained 91% of the variation in leaf area. Since only a single linear measurement is required, the model: Leaf area = 1.06+0.4731L², is recommended for predicting leaf area in S. macrocarpon.

Keywords: Eggplant, Solanum macrocarpon, Leaf area, Leaf area meter, Leaf area model