The world's first blue roses have been unveiled to the public for the first time at an international flower fair in Japan, following nearly two decades of scientific research.

The blue-hued blooms are genetically modified and have been implanted with a gene that simulates the synthesis of blue pigment in pansies.

The flowers, which were on public display at the International Flower Expo Tokyo, will go on sale commercially in Japan in Autumn next year.

"This is the first time that these blue roses have been put on display in public," said Megumi Mitsunaga, a spokeswoman for IFEX.

"They are attracting lots of attention here because they are so unusual."

The creation of blue flowers - ¬historically viewed as a symbol of the impossible - was masterminded by a subsidiary of Suntory, the Japanese drinks company, which has invested three billion yen in the creation of blue roses, blue carnations and other blue flowers since 1990.

Its scientists successfully pioneered implanting into the flowers the gene that produces Delphinidin, the primary plant pigment that produces a blue hue but is not found naturally in roses.

The world's first genetically modified blue roses were unveiled in the laboratory four years ago, although further research was required to make them safe to grow in nature.

Following the cultivation of test batches in the United States and America, the company will be ready to sell them from next year and aims to open up a global market for blue flowers worth an estimated 30 billion yen.

The blue roses were among 860 exhibits on display at the fifth annual IFEX, the largest flower and garden trade show which is expected to attract over 32,000 visitors over the weekend.

Other highlights included glow-in-the-dark roses showcased in an array of pastel hues in dark boxes, having been genetically modified to light up in the dark.