Modern rose hybrids have a worrying lack of genetic diversity

Modern commercial roses have lost over a quarter of their genetic diversity compared with older varieties, which could leave them vulnerable to diseases or climate change.

Roses have been admired and grown since antiquity, when people in Asia and Europe began cultivating ancient varieties from a dozen wild rose species. There were less than 100 varieties before 1800, but by 1900 there were around 8000 varieties of crossed Asian and European…