Tyson Raper and Larry Steckel
During the 2014 growing season, the University of Tennessee Cotton Variety Testing program was given an opportunity to evaluate several of the new Monsanto Bollgard II® XtendFlex™ cotton varieties. Given the recent de-regulation of this trait, many may find this data of interest. (De-regulation of dicamba applications to these varieties is still pending.)
Two regulated trials were established; one at the West Tennessee Research and Education Center in Jackson, TN (planting date 5/20) and one at the Milan Research and Education Center in Milan, TN (planting date 5/23). Scientists from Monsanto provided the program with 9 XtendFlex varieties and 4 non-regulated, commercially available standards (DP 1311 B2RF, DP 0912 B2RF, PHY 499 WRF, and ST 4946 GLB2). These varieties were arranged in a randomized complete block design and all crop material was destroyed after collecting measurements.
As a disclaimer, these trials (like much of the cotton in West TN) suffered through one of the wettest Junes on record. Subsequently, maturity was delayed and later-maturing varieties were unable to compensate. Given these conditions, yield-ranks will most likely change in a more rainfall-normal year.
Still, these results suggest the ‘yield-drag’ associated with the introduction of new traits in other commodities does not appear to be present with the XtendFlex cotton platform. This data further reinforces a statement made in the TN Variety Trial Results post a few weeks ago; TN cotton producers selecting varieties for the 2015 season have several viable options across a wide range of tech-trait platforms.