Cabbage and broccoli leaf area estimations from linear measurements

Accurate and nondestructive methods to determine individual leaf areas of plants are a useful tool in physiological and agronomic research. Determining the individual leaf area (LA) of Brassicaceae family such as red cabbage (Brassica oleracea var. cappitata L. f. rabra ), cabbage (Brassica oleracea var. cappitata L. F. alba) and broccoli (Brassica oleracea var. italica L.) involves measurements of leaf parameters including: length (L) and width (W), or some combinations of these parameters. This research was carried out during 2008 (on eight cabbage, six broccoli, and three red cabbage genotypes) under open field conditions, to evaluate whether an equation could be developed to estimate leaf area of cabbage and broccoli across genotypes. Regression analysis of LA vs. L and W revealed several equations that could be used for estimating the area of individual cabbage and broccoli leaves. A linear equation having W as the independent variable provided the most accurate estimate of red cabbage and cabbage LA. The linear equation (LA = a + bW2) exhibited a high accuracy and precision in estimating red cabbage and cabbage LA. For broccoli a linear equation having LW as the independent variable provided the most accurate estimate of LA, but doubled the time required for leaf measurement.