Estimation of leaf area index using allometric relationships in Cucurbita pepo L.

Prediction of the leaf area is essential in crop simulation models. The objective of this study was to find relationships between leaf area index (LAI) and numbers of leaves (NL), leaf dry weight (LDW), leaf fresh weight (LFW), number of nodes (NN) and plant height (PH), in Pumpkin (Cucurbita pepo L.). For this purpose, an experiment was conducted using three planting dates (20 April, 21 May, 21 June) at the research field of Aburaihan Campus, the University of Tehran, Pakdasht, Tehran, Iran, in 2009-2010 cropping season. The experimental design was randomized complete block with four replications. Sampling was performed during the whole growing season. In each sampling LA, NL, LDW, LFW, NN and PH, were measured. Various equations were used to describe relationships between LAI and aforementioned characteristics. The best result was obtained a simple ln-transformed linear equation {ln(y)= a+b×ln(x)}. Results showed that significant relationships were found between LAI and LA (R2 = 90), LAI and NL (R2 = 90), LAI and NN (R2 = 90), LAI and LDW (R2 = 98) and LAI and LFW (R2 = 98). These equations LAI can be used for estimation in simulation models of Pumpkin as well as for the fast and easy estimation of LAI, especially where there is no LAI-meter available.