Agricultural researchers have cultivated several new species of flowers for display during the city's 2010 World Expo.

The flowers, grown by Shanghai Jiao Tong University's agricultural school, include two new species of petunia and a scarlet periwinkle - a rare color for both the domestic and foreign flower markets.

"We are particularly excited about the new scarlet variety which has been cultivated solely with domestic technology developed by ourselves," said Cai Run, a Jiao Tong professor and research program leader. Since 2005, Cai and his research team have been working on a program searching for flowers which will be in bloom during the May to October Expo period.

"Most flowers blossom in spring, so it's difficult to find a species that can flower throughout the five months from early summer to autumn," Cai said.

Also, Shanghai has its wet "plum rain" season in June and July and a scorching summer afterwards, so expo flowers had to be able to endure both heavy rain and high temperatures. Both are weather conditions that ordinary flowers couldn't be expected to survive.

Another plus with the new flowers is that each of the three species has a pure color with multiple buds - ideal for the Expo, Cai said.

Most of the country's flower and grass species for gardens are introduced from abroad. He said new home-bred species will probably cost less to cultivate.

The three species have now passed the initial expo flower selection by a panel of local experts. They are expected to complete the registration and patent application requirements before large-scale manufacturing by the end of this year.