Japanese scientists have genetically engineered a chrysanthemum flower that is "true blue" — a color that has long eluded flower breeders and researchers.Blue has proved a challenge to produce in many other popular flowers, including roses, carnations and lilies.It hasn't happened until now in chrysanthemums due to the "recalcitrant and unpredictable expression of introduced genes," Naonobu Noda from Japan's National Agriculture and Food Research Organization tells The Two-Way. Noda is the lead author of the paper released today in Science Advances.When scientists tried previously to introduce genes to create a blue color, Noda said, the flower would "shut them off by as yet unknown mechanisms." Other attempts produced violet flowers, not blue ones.The researchers then took genes from two very blue flowers — butterfly peas and Canterbury bells — and snuck them into the chrysanthemum.Those two genes modified the chrysanthemums' natural pigment to create a colorful molecule called delphinidin.(Interestingly, delphinidin is also found in Cabernet Sauvignon grapes).The scientists said the petals only turned a brilliant "true blue" due to an interaction between the delphinidin and the chrysanthemum's other, colorless compounds. How do you define "true blue"? The Royal Horticultural Society has strict parameters, as defined by its color charts:Noda says that this is a simpler process than they were expecting to have pigments express blue coloration, and adds that the technique might be applicable to other flowers, like roses and lilies.Chrysanthemums are the most popular flower in Japan, according to The Associated Press. Here's more from the wire service: