Abstract
Hybrid maize was one of the first examples of genetic theory successfully applied to food production. When first introduced, it seemed almost miraculous; sturdy hybrids convinced sceptical farmers that 'the professors' and their arcane science could do them some good. Strangely, the genetic basis of heterosis (hybrid vigour) was and still is unknown. But to this day, newer hybrids continue to outyield their predecessors; they do so because they are tougher and healthier.