Evaluation of Bentazone Reaction by Growth Stage and Bentazone Dose Across Soybean Genotypes

Germplasm screening is time-consuming, labor-intensive, and expensive. Therefore, it is important to develop the most effective selection method for plant breeding and genetic studies. Herein, experiments were conducted to determine the optimal growth stage and application dose of bentazone based on the response of soybeans. The influence of soybean accessions, application doses (0X, 1X and 2X), and growth stages (VC, V1, V2) on plant injury and growth performance was examined. Leaf injury and growth performance were significantly influenced by accession, dose, and growth stage. There was a substantial difference of 2%-3% and 23%-31% in leaf necrosis between the tolerant and susceptible groups, respectively. The mean leaf necrosis and visual scores for the VC, V1, and V2 stages showed a similar pattern, with a non-significant difference. The effect of accessions on plant height, fresh weight, and dry weight reduction had no significant difference in all growth stages. No significant differences in necrosis were found in the tolerant accessions across bentazone doses, while significant differences were found in the susceptible accessions. The leaf necrosis from 2X bentazone was almost double that of 1X treatment. However, there was no difference in visual scores between the 1X and 2X doses. In addition, the visual scores showed no difference between the 1X and 2X doses within the growth stages. The application of 1X dose bentazone at the V1 stage is suitable to determine tolerant and susceptible soybeans. This result can help determine the genotypes for breeding and genetic studies.