I figure with the $2.00 premium I receive, I can have an 8 bushel decrease in yield and still break even at $13 CBOT. That is figuring buying seed, not planting bin run. For every dollar beans drop on the CBOT, the % of the premium increases, so if we ever drop down to $8 beans the premium will make an even bigger difference.
We had a plot back in 2009 with quite a few conventionals and RR beans. There wasn't a lot of difference, they were all within 5 bpa. RR's were the best yield but also the lowest. With some of the new releases from ISU, many of the new varieties are keeping pace with the new RR2's.