Physiological Effects of Late Season Glyphosate Applications on Peanut (Arachis hypogaea) Seed Development and Germination

摘要

Field studies were conducted to determine runner type peanut response to glyphosate at 80, 160, 240, 320, and 470 g ae/ha applied 75, 90, and 105 days after planting (DAP) at Plains and Ty Ty Georgia in 2006 and 2007. Data collected included seed kernel mass, peanut pod yield, and seed germination. The two-way interaction between DAP and glyphosate rate was not observed for any variable. Data indicated that glyphosate applied at 75 DAP reduced peanut seed mass to 643 mg/kernel, which was less than the 90 or 105 DAP application masses of 669 and 665 mg/kernel, respectively. This could be attributed to the timing of that application when peanut was in the beginning of pod fill or R3 growth stage of development. Peanut physiological response to glyphosate was reflected in peanut seed mass. As glyphosate dose increased, peanut seed mass decreased. Seed masses following glyphosate at 80, 160, 240, 320, or 470 g/ha were 669, 674, 662, 645, and 625 mg/kernel, respectively, as compared to 678 mg/kernel for the nontreated control. When glyphosate was applied at 80 or 160 g/ha, peanut pod yield was similar to the nontreated control. At glyphosate rates of 240, 320, and 470 g/ha, peanut pod yield was reduced to 88, 76, and 64% of the nontreated control. Peanut pod yield was reflective of the reductions in seed mass with increasing glyphosate rate which reduced yield. Seed germination was 96% and greater, which indicated that glyphosate applied at any rate or timing did not affect viability compared to the nontreated control.