Impact of the MON89788 Event for Glyphosate Tolerance on Agronomic and Seed Traits of Soybean

Glyphosate [N-(phosphonomethyl)glycine] is a popular herbicide for weed control in fields planted to soybean [Glycine max (L.) Merr.] cultivars with a transgene that provides tolerance to the chemical. A transgenic event MON89788, known commercially as Roundup Ready 2 Yield (Monsanto Co., St. Louis, MO), was developed by the Monsanto Co. as an alternative to the event 40-3-2 for glyphosate tolerance in soybean. The objective of our study was to compare the agronomic and seed traits of glyphosate-tolerant (GT) lines and glyphosate-susceptible (GS) lines from populations segregating for MON89788. The transgene was backcrossed into three GS cultivars to develop BC2 populations. There were 27 GT and 27 GS BC2F2-derived lines from each backcross population evaluated at four Iowa environments in 2010. The means of the GT lines were not significantly different from the GS lines in any of the populations for seed yield, lodging score, and palmitate, oleate, and linoleate concentrations. The maximum significant difference between the means of the two types was 0.4 d for maturity date, 2 cm for plant height, 5 mg sd(-1) for seed weight, and 2 g kg(-1) for protein, 1 g kg(-1) for oil, 1 g kg(-1) for stearate, and 0.2 g kg(-1) for linolenate concentrations. The significant differences among lines within each type and the overlap in their distributions for all of the traits indicated that it would be possible to select GT or GS lines with comparable performance from populations developed by crossing a GS parent to a GT parent with the MON89788 event.