With the right breeding and care, food plants have – so far – fed and sustained human civilisation. But how much can be grown, where and how reliably are emerging themes in the food security debate. Forty years ago, a non-patented gene from a quaint old grain saved the world-leading, multi-billion dollar US corn industry. It was fortunate for the multinational seed, fertiliser and pesticide conglomerates that someone in China had the foresight to conserve it.