It's true that Gordon's explanation of "yield drag" (consistently lower yields from GM crops than conventional) is a sweeter one for Monsanto than a plain genetic one: ie to get performance of a specific nature from an engineered plant, you inevitably have to sacrifice yield. (That, btw, is the opinion Marie-Monique Robin stated the other evening.)

Still and all, he's saying you need to sprinkle some Mg fairy dust over the field on top of the rest. So what was meant to simplify farmers' lives (easy weedkilling) turns out to be less simple (and more costly) than promised.