Physiological Performance of Seeds and Level of Herbicide Residues Depending on Application of 2.4-D in Wheat

ABSTRACT: Horseweed control through application of 2.4-D in the winter season is an alternative to manage biotypes resistant to herbicides that belong to other mechanisms of action. The objectives of this study were to assess the physiological quality of wheat seeds and determine the rate of 2.4-D residue, as function of application stages and herbicide rates. The treatments were arranged in factorial scheme, with three application stages (flowering, soft dough and hard dough), and four 2.4-D rates (0; 504; 1,008 and 2,015 g a.i. ha-1). The application of 2.4-D in the wheat crop changed physiological seed quality by increased the rate and total percentage of germination. The application of 2.4-D resulted in herbicide accumulation in seeds, especially when application was carried out at the soft dough stage. Also, the increase in herbicide rate increased the level of residue in the seeds. However, regardless of stage of application for 2.4-D and herbicide rate in use, the values of residue found in the seeds were below the allowed maximum limit.

摘要：冬季施用2,4-滴（2,4-D）防控小飞蓬（Horseweed），是治理具有其他作用机制除草剂抗性生物型的有效替代方案。本研究旨在评估小麦种子的生理品质，并探究施药时期与除草剂用量对2,4-滴残留量的影响。试验采用因子试验设计，设置3个施药时期（扬花期、乳熟期、蜡熟期）以及4个2,4-滴施用剂量（0、504、1008、2015 g a.i.·ha⁻¹，其中a.i.为有效成分）。在小麦田中施用2,4-滴，可通过提升发芽势与总发芽率，优化种子生理品质。施用2,4-滴会导致除草剂在种子中积累，尤其在乳熟期施药时积累量更为显著；同时除草剂用量的增加会进一步提高种子中的残留水平。但无论2,4-滴的施药时期与所用除草剂剂量如何，种子中检出的残留量均低于法定最大残留限量。