A Rapid and Non-Destructive Method to Determine the Leaflet, Trifoliate and Total Leaf Area of Soybean

摘要

The importance of rapid, non-destructive, 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 soybean (Glycine max L.). This study aimed to develop prediction equations for estimating leaflet, trifoliate and total leaf areas using maximum length, L (cm), width, W (cm), length and width product, LW (cm) and green leaf drymatter, DM (g) of soybean leaves. For this purpose, an experiment was conducted using three cultivars of soybean ('Dpx', 'Sahar' and 'Williams'), in 2009-2010, in the Faculty of Agronomy, Gorgan, Iran. During the growing season, leaves of randomly selected soybean plants were collected. Leaf area was measured with a digital leaf area meter, related dry matter also was weighed, leaf dimensions were determined with a ruler, too. Statistical analyses of soybean leaf areas were divided into three levels: leaflet, trifoliate and total leaf area. At each level, the predictive abilities of three regression equations (linear, power and binomial) were compared, with different independent variables for each equation. Our data indicate, however, that considerablesavings of time, with little loss of predictive ability, could be possible by measuring only W or LW in each instance. In general, these analyses indicated that a single regression equation could be used at each level. Our findings revealed that pooled-based models (without respect to cultivar) are reliable for estimating leaflet, trifoliate and total leaf area. Researchers can use these models readily and without any inconvenience to save time and costs, especially where there is a lack of related equipment to measure leaf area.