Edamame [Glycine max (L.) Merr.] is a specialty crop with untapped potential in the Midwest. Adoption of edamame in the Midwest has potential due to similarities in production practices to grain soybean and the potential for higher return per acre. Additionally, USA is experiencing expanding market opportunities and rising consumer interest in locally grown edamame. Despite these benefits, limited research exists on suitable edamame varieties for this region, and effective weed control remains crucial for Midwest edamame adoption. Our research aimed to identify currently available varieties of edamame with rapid germination response, with and without weed competition. Six readily available varieties of edamame (Chiba green, Sayamusume, BeSweet 292, Midori Giant, Tohya, and Karikachi) were grown with and without velvet leaf (Abutilon theophrasti Medik.) competition. Weed seeds were planted using three timing treatments: two weeks before edamame planting (PRE), simultaneously with edamame (SIM), and two weeks after edamame planting (POST). Two control treatments without weeds (‘Control 1’ and ‘Control 2’) were also incorporated. This study was designed as an RCBD split-plot design with three replications, with variety as the main plot and timing of weed competition as the split-plot under greenhouse conditions. Edamame emergence rate, plant height, LA (leaf area), and dry weight for both edamame and weed were measured. At 5 and 9 DAS (days after seeding), edamame emergence was significantly higher without weed competition (71.76% and 95.37% in ‘Control 2’ treatment) compared to when weeds had a head start (46.53% and 72.69% in ‘PRE’ treatment). At 9 DAS, edamame emergence was significantly higher when edamame had a head start (93.06% in ‘POST’ treatment) compared to when weeds emerged first (72.69% in ‘PRE’ treatment). In terms of emergence rate, Karikachi showed superiority (78.89%) compared to Midori Giant (39.17%) at 5 DAS, but there was no difference among varieties at 9 DAS. Timing of weed planting affected edamame height, LA, and edamame dry weight. Edamame height and dry weight were reduced by 11.67% and 5.71 % by weed competition when weeds were planted two weeks earlier than edamame. Edamame competition significantly reduced weed dry weight by 93.94% when weeds were planted two weeks later and by 84.85% when planted the same day, compared to weeds established two weeks before edamame. Weed competition reduced edamame LA by 29.189 cm² when weeds were planted simultaneously with edamame compared to two weeks after edamame planting (241.582 cm² in ‘SIM’ vs 270.771 cm² in ‘POST’).
