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）防治小飞蓬（Horseweed），是治理作用机制各异的除草剂抗性生物型的替代方案。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施用量对2,4-滴残留量的影响。试验处理采用析因设计，设置3个施药时期（扬花期、软仁期、硬仁期）与4个2,4-滴施用量（0、504、1008、2015克有效成分/公顷）。小麦田施用2,4-滴可通过提升发芽速率与总发芽率，改变小麦种子的生理品质。施用2,4-滴会导致种子中除草剂残留累积，尤其在软仁期施药时更为显著。此外，除草剂施用量的提升会增加种子中的残留水平。但无论2,4-滴的施药时期与施用量如何，种子中检测到的残留量均低于法定最大残留限量。