Opponents of genetic crop modification sometimes point out that similar results can be achieved by applying modern technology to conventional plant breeding techniques. But that is not true of bananas – a crop important not only for the ripe yellow “dessert bananas” of the commercial fruit trade but also for the green “cooking bananas” and plantains that are a calorie-rich staple across much of tropical Africa.

The main varieties of dessert and cooking banana are sterile – and propagated vegetatively – which makes them very hard to improve through conventional breeding. So they are a tempting target for GM.

Howard Atkinson, a plant science professor at Leeds University, is working with the International Institute of Tropical Agriculture to make GM bananas that resist nematode worms – tiny pests that eat their roots and cause huge crop losses in sub-Saharan Africa.