Geoffrey Lean writes that GM crops are not at the fore-front of increases in crop yields. Traditional methods involving cross pollination are far more successful.
http://www.telegraph.co.uk/earth/agriculture/geneticmodification/10064255/The-inconvenient-truth-about-GM.html
http://www.telegraph.co.uk/earth/agriculture/geneticmodification/10064255/The-inconvenient-truth-about-GM.html