WEIGHT OF LEAVES AS A TOOL FOR ESTIMATING THE SOYBEAN LEAF AREA

Abstract

Measurements of leaf area are important in yields damage studies, but the equipment needed may not be available for every one. Therefore, the use indirect comparisons with weight of fresh or dried leaves may help in estimating leaf area. This research studied the relationship between leaf weight and leaf area in plants sampled at the growth stage R7.1 from 64 field plots of Nidera 5909 RG soybean cultivar. The leaves were weighted soon after sampling for fresh weight and again after 48 hours of incubation at 65° C for dried weight. Leaf area was measured with a Licor digital leaf area meter. The model equations were significant (p < 0.0001, R² 0.74 to 0.97) for each plant part (lower, medium, or upper third) and for the whole plant. In average, leaf area (y) was estimated as y = 45.53x + 19.03 from fresh weight (x) and as y = 176.17x – 75.30 for dried weight (x). This tool was shown potentially viable to estimate plant leaf area. The method based on dried weight is more labor consuming but does not require leaves being weight soon after sampling. The use of such comparisons for other soybean cultivars may require additional validation studies.