The world cultivation of genetically modified (GM) soybean resistant to glyphosate is increasing and the presence of these seeds in lots of conventional seeds has became a problem for international soybean trade. Recognizing the importance of the new markets and GM products, Seed Technology will have to assure the genetic purity of the biotechnologically derived products through reliable, practical and low cost tests. In this context, the aims of this study were to verify the efficiency of the germination test with herbicide in the substratum (bioassays) in the detection and quantification of GM soybean seed mixtures in conventional seed samples. Samples of conventional seeds were prepared with 0, 1, 3 and 5% GM soybean seeds and submitted to the procedures of pre-soak, soak and immersion in herbicide, installed in plastic trays containing 25 seeds, with and without association to the GMO detection kit. In the sequence, contaminated samples with 0, 1, 3, 5 and 8% GM soybean seeds were installed in paper rolls (25 and 50 seeds/roll) and plastic trays with 25 seeds following the pre-soak procedure in herbicide. Six days after the installation, hypocotyl length, root length, number of secondary roots and the largest secondary root length were evaluated. The pre-soak procedure is the appropriate for the detection and quantification of GM soybean seed presence, permitting 100% successes in the detection, regardless of the contaminant percentage in conventional samples of soybean seeds and it presents accuracy in the quantification of GM soybean seed presence of up to 3% in conventional samples, and its precision is conditioned to the percentual of present mixture in the sample.
Glycine max; transgenics; herbicide; germination
