Estimation of Leaflet, Trifoliolate, and Total Leaf Areas of Soybeans¹

Abstract

The importance of rapid, nondestructive, and accurate measurements of leaf area for agronomic and physiological studies is well known. Several mathematical formulas have been derived for estimating leaf areas for numerous crops, but there is little information available for soybeans [Glycine max (L.) Merr.]. The purpose of this study, therefore, was to develop prediction equations for estimating leaflet, trifoliolate, and total leaf areas of soybeans. Statistical analyses of soybean leaf areas were divided into three levels: leaflet, trifoliolate, and total leaf area. At each level, we compared the predictive abilities of three regression equations, each involving a different independent variable. On the basis of these results, we chose one independent variable at each level for subsequent regression analyses of various hypotheses. Prediction equations derived from independent variables involving measurements of length and width were superior at each level to those involving measurements of only length or width. Our data indicate, however, that considerable savings of time, with little loss of predictive ability, could be possible by measuring only length or width in each instance. With the use of independent variables involving measurements of length and width, regression analyses were performed to assess the effects of cultivars at each level and also the effects of leaflet orientation on the trifoliolate and the trifoliolate position on the plant at their respective levels. In general, these analyses indicated that a single regression equation could be used at each level. Leaflet, trifoliolate, and total leaf areas of the 12 cultivars we studied could be estimated by the following equations, respectively: A = 0.624 + 0.723LW (R2 = 0.985); A = 0.411 + 2.008LW (terminal leaflet) (R2 = 0.983); A = 6.532 + 2.045 (∑L1W1 terminal leaflets) (R2 = 0.965).

Allometric Method to Estimate Leaf Area Index for Row Crops

“…Aase (1978) showed significant correlations between leaf area and aboveground dry matter of winter wheat. McKee (1964) and Wiersma and Bailey (1975) used leaf length and width to estimate leaf area of corn and soybean, respectively. Stewart and Dwyer (1999) developed polynomials describing leaf width for different corn hybrids, and integrated the polynomials to calculate leaf area.…”

Morphological and physiological changes in esterase and lipid peroxidation of two bean cultivars pre-soaked with potassium nitrate under salt stress

“…The soluble proteins were determined according to the method by Lowery et al [31]. Leaf area measurements were carried out according to Wiersma and Bailey [48]. The level of lipid peroxidation was measured in terms of MDA content, as MDA is a product of lipid peroxidation following the method of Heath and Packer [24].…”

Growth, assimilate partitioning and grain yield response of soybean (<i>Glycine max</i> L. Merrrill) varieties to carbon dioxide enrichment and arbuscular mycorrhizal fungi in the humid rainforest

“…Non destructive growth variables (number of trifoliate leaves per plant and trifoliate leaf area) were determined at 3, 6 and 9 WAP in one set of pot. Total leaf area of the crop was calculated using the equation derived by Wiersma and Bailey (1975): A = 0.411 + 2.008 LW; where A is trifoliate leaf area, and L and W are the maximum length and maximum width of the terminal leaflet of a trifoliate leaf, respectively.…”