Table 1: Percent reduction in soybean fresh weight and dry weight at harvest (40 days after emergence) caused by early season interference by Palmer amaranth in greenhouse experiment.a,b

Palmer amaranth biotypeFresh weight reductionDry weight reduction

Individual Palmer amaranth biotypesc
 Emanuel (GR)24ab23ab
 Macon (GR)31a28a
 Wayne (GR) 13b 11b
 Crisp (GS)31a26a
 Emanuel (GS)37a31a
 Johnston (GS)26ab24ab
Palmer amaranth biotypes grouped by response to glyphosated
 GR group23z21z
 GS group31y27y

a Data are pooled over runs of the experiment. Abbreviations: GR, glyphosate resistant; GS, glyphosate susceptible.
b Means within a parameter and analysis followed by the same letter are not significantly different according to Fisher’s Protected LSD test at P ≤ 0.05 for fresh weight reduction and P ≤ 0.10 for dry weight reduction.
c Consists of six Palmer amaranth biotypes.
d Consists of a group of three glyphosate-resistant (GR) and a group of three glyphosate-susceptible (GS) Palmer amaranth biotypes.