China will not carry any plant seeds aboard Shenzhou VI, its second manned spacecraft, a senior official said Monday. The announcement came after media reports speculated that the spacecraft would carry seeds, animal semen or other experimental items for space mutation breeding.

"Since Shenzhou V, which took the first Chinese astronaut Yang Liwei 14 times around the earth for a 21-hour period in 2003, space experiments in China have been focusing on human activities in outer space," Liu Luxiang, director of the Center for Space Breeding under the Beijing-based Chinese Academy of Agricultural Sciences, told China Daily yesterday in a telephone interview.

The second manned space mission, expected to be launched this week, will carry two astronauts into orbit for five days, during which their physical reactions will be closely monitored.

"If it were an unmanned spaceship or recoverable satellite, we might have put experimental things on it," said Liu, whose department selects seeds for outer space experimentation and allocates them to breeding nurseries after they are brought back.

"An unmanned spaceship and a recoverable satellite could have a relatively looser security demand and could expose seeds to more cosmic radiation to cause a useful mutation," he said.

"But as a manned capsule, the Shenzhou VI has a different structure to block radiation as much as possible, and strict measures are being taken to ensure its security."

Liu had obtained evidence from other sources but refused to identify them, saying only: "China's style is to focus on one thing at a time."

He also denied that the absence of seeds is due to limited space on the capsule.

Since 1987, China has been keen on sending plant seeds about 200 to 400 kilometers above the earth to study genetic mutations and changes.

A variety of seeds, including corn, lotus and watermelon, have traveled in space for up to two weeks in recoverable satellites or high-altitude balloons.

The high radiation in space-mutated, or genetically-modified, seeds' DNA, may explain why peonies grown from "space seeds" are larger and more colorful than normal. The mutations may also explain jumbo bell peppers and fast-growing rice.

In the past five years, the Center for Space Breeding developed 12 rice and wheat variants that greatly increased grain output, according to a statement released last month by the center.

(China Daily October 11, 2005)