Effect of Glyphosate on Growth, Chlorophyll, and Nodulation in Glyphosate-Resistant and Susceptible Soybean (Glycine max) Varieties

Publisher Website
Google Scholar
Abstract
Greenhouse and growth chamber experiments were conducted to examine glyphosate [isopropylamine salt of N-(phosphono-methyl) glycine] effects on growth, chlorophyll content, nodulation, and nodule leghemoglobin content of glyphosate-resistant and susceptible soybean (Glycine max[L.] Merr.) varieties. In susceptible soybean, a single application of 0.28 kg/ha reduced chlorophyll content (49%), and shoot and root dry weight (50 and 57%, respectively) at 2 wk after treatment. In glyphosate-resistant soybean, there were no significant effects on these parameters by single application up to 1.12 kg/ha, but 2.24 kg/ha reduced shoot and root dry weight by 25 to 30%. Application of glyphosate 1.12 kg/ha, followed by sequential applications at 0.56 or 1.12 kg/ha, did not affect plant growth and chlorophyll content, but application of 2.24 kg/ha followed by sequential application of 2.24 kg/ha reduced root growth. In glyphosate-resistant soybean, an application of 1.12 kg/ha 3 wk after planting did not affe...