Estimation of individual leaf area, fresh weight, and dry weight of hydroponically grown cucumbers (Cucumis sativus L.) using leaf length, width, and SPAD value

Non-destructive and mathematical approaches of modeling can be very convenient and useful for plant growth estimation. To predict individual leaf area, fresh weight, and dry weight of a cucumber (Cucumis sativus L.), models were developed using leaf length, leaf width, SPAD value, and different combinations of these variables. Eight regression equations, commonly used for developing growth models, were compared for accuracy and adaptability. The three nonlinear models developed were as follows: individual leaf area (LA)=-210.61+13.358W+0.5356LW (R-2=0.980***), fresh weight (FW)=-2.72+0.0135LW+0.00022LWS (R-2=0.956**), and dry weight (DW)=0.25-0.00102LS+ 0.000077LWS (R-2=0.956***), where L is the leaf length, W the leaf width, S the SPAD value, and LWS=LxWxS. For validation of the model, estimated values for individual leaf area, fresh weight, and dry weight showed strong agreement with the measured values, respectively. Leaf dry weight, especially, was estimated with a higher degree of accuracy through the use of a SPAD value, as well as leaf length and width. Therefore, it is concluded that models presented herein may be useful for the estimation of the individual leaf area, fresh weight, and dry weight of a cucumber with a high degree of accuracy. (c) 2006 Elsevier B.V. All rights reserved.