Abstract

The large-scale cultivation of Roundup Ready (RR) has recently increased among Brazilian farmers. However, few studies have compared the intrinsic characteristics of the seeds of RR soybean cultivars and their respective conventional parental. Thus, the purpose of this study is to verify if the genetic modification of the RR soybean affects the lignin content and its monomeric composition in the seed coats, in comparison with the parental cultivar. To do that, five groups, each one with a RR cultivar and its respective parental were selected. After the physiological analysis of the seeds, the coats were separated and dried in an incubator at 80°C for 24 h. Next, the contents of lignin and its monomers p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) were determined. In order to compare the RR cultivars and their respective parents, a statistical evaluation of contrasts was performed. The results revealed that only the group BRS133 vs BRS245RR was different; the transgenic cultivar showed significant increases in the lignin contents and their monomers. In conclusion, the introduction of the sequence CP4-EPSPS in the genome of soybean cultivars, had no any influence on seed coat lignification.

Key words: Monolignols, seeds, Glycine max L. Merrill, Roundup^âReady.