Which Bt traits do you need to buy? LINCOLN — When it comestobuyingcornseed, one way to save money is to ensure you are not investing in GMO insect protection traits you do not need for your particular farm or field. Traited corn has been genetically modified to express one to five of the nine Bt proteins commercially available. The ...PLEASE LOG IN FOR PREMIUM CONTENT. Our website requires visitors to log in to view the best local news. Not yet a subscriber? Subscribe today!