Heirloom tomatoes are less genetically diverse than standard varieties

A study of traditional ‘heirloom’ tomato varieties from Europe has revealed little genetic diversity despite their enormous variety in size, shape and colour

By Michael Le Page

Yellow, streaked or purple, enormous or tiny, round, plum or lobed – the colours, sizes and shapes of the tomato varieties traditionally grown in Europe vary greatly. But it turns out this diversity is only skin deep. Apart from the few genes controlling these obvious characteristics, these tomatoes are virtually identical genetically.

“It’s like a desert with some oases of variety,” says Jose Blanca at Valencia Polytechnic University in Spain. “The tomatoes that you find in the supermarket nowadays, they have …