If a farmer plants the same crop three seasons in a row he might like to have the non-terminating, but if he plants winter wheat and regular wheat he gets paid by the purity as part of his yield and therefore, would prefer the terminating, having no left over seeds growing within his ranks. Also he can plant GM one year when needed for Ethanol and then another type later for another purpose. Which means it is a very good thing not to mix and this solves a need of the market, purity of product and higher prices paid to the farmer (who is leveraged on the commodity side also so he is downside protected in case of poor yields that season), it ain