Until 1982 the large-scale cultivation of rubber in China had been regarded as impossible because it was north of the "rubber belt" - a zone extending 10 degrees in either direction from the equator where the temperatures are high enough and steady enough for this delicate tree to thrive. So it came as a surprise to the world to learn that over the past 20 years China has moved up to the No. 4 position among the world's 43 rubber-producing countries in acreage of rubber trees and the No. 5 spot in annual output of dried rubber.

The news started to come out when the state awarded Professor Huang Zongdao, currently president of the South China College of Tropical Plants and the South China Research Academy of Tropical Plants, a first prize for invention in 1982 for his work on developing hardy strains of rubber trees. Then last year Prof. Huang addressed an international rubber conference in Beijing, astonishing the participants with the facts about China's rubber production and research, especially the advances made in developing test-tube pollination and cold-resistant varieties.

Huang lives and works in Danxian County in the centre of Hainan Island which produces 70 per cent of China's rubber. He arrived there in 1958 when the Institute of Tropical Plants (the predecessor of the present research academy) was transferred from Guangzhou under the leadership of He Kang, the current Minister of Agriculture, Animal Husbandry and Fishery, to develop China's rubber plantations.

"At that time, there was only a arge piece of wasteland covered with thorny undergrowth haunted by wild animals, snakes and centipedes," said Huang at his office. "All the experts and professors lived in thatched huts. Our experimental station was more than 20 kilometres away from where we lived and we had to go there and back on foot."

It was a far cry from the pleasant white-washed building now in use. Shaded by tropical trees, it has eight large characters on its front wall, a message of encouragement from the late Premier Zhou Enlai: "Brace your mind and take root in the treasure island." And that was what Huang and the other scientists did.

"Rubber was originally produced in the tropical forests of the Amazon basin," Huang explained. "Before liberation, there were only a few rubber trees on Hainan, brought back by overseas Chinese. They were scattered in the mountain valleys. Because Hainan is situated more than 15 degrees north, it was considered by many people to be a 'forbidden zone when it came to growing rubber trees. We weren't sure then if rubber trees could be planted here on a large scale.

"Our early efforts suffered two major setbacks. The first one was wind. There is almost no wind in the tropical forests in Brazil. But Hainan is often struck by typhoons. One big typhoon destroyed half the rubber trees we had already planted.

"The second setback was caused by cold temperatures. We didn't know that rubber trees were so sensitive to cold. One cold spell destroyed the tens of thousands of hectares of young rubber trees we had nursed through hard work. We didn't lose heart, however. We discovered that the roots of some of the trees were still alive, and we dug them up one by one and replanted them. Today all the rubber trees on Hainan are descendants of those which withstood the cold."

Huang majored in agriculture in Jinling University in Nanjing, specializing in the cultivation of rice and wheat. He switched to rubber 30 years ago because the state needed his expertise and brought his family with him to Hainan. "Today one million people in China are engaged in rubber cultivation," Huang said. "The first prize for important inventions awarded by the state in 1982 was the fruit of the joint efforts of all nne millin."

He pointed out that China, besides learning from other rubber-producing countries, has had to develop its own methods because of certain peculiar conditions. "If you were to survey our rubber plantations from the air, you would see that they are made up of small plots, each with windbreaks on all four sides. This is unique to China. To grow rubber on a large scale, it was necessary to breed some cold-resistant varieties.

"We have also succeded in nursing rubber seedlings directly from pollen in test tubes. Scientists in Malaysia, which is advanced in rubber cultivation, spent years nursing rubber seedlings in test tubes. They finally suceeded in early 1977. But the young rubber tree died later. We succeeded in this field in late 1978. You can go and see our test-tube rubber trees behind this building. Most of them are now eight or nine metres high, and many of them have been transplanted.

"After the international rubber conference in Beijing last year, representatives from many countries came to visit the research centre. They were greatly interested in our methods. The president and supervisor of the Malaysian state rubber research academy, after visiting here, acknowledged that China leads the world in some aspects of rubber cultivation. Of course, they have many things which we can learn.

"We have also devised some methods to change the chromosomes of the rubber trees to improve their hereditary traits. This is another important breakthrough.

"In addition, we have devised a method to predict the rubber trees' output. In other countries, this can be done through trial tapping only after the rubber trees have basically become a forest. This method results in a waste of manpower and materials. With our method, the output can be forecast just by picking one leaf of a young rubber tree. When our experts made some on-the-spot demonstrations in other countries, the people there were astonished."

Hainan produces 100,000 tons of dried rubber every year. This, however, still falls short of national demand, and China is still the world's third largest buyer of natural rubber.

"At present, Hainan Island has a rubber planting area of 267,000 hectares," said Huang. There are still 133,000 hectares of wasteland which can be converted to rubber plantations. The per-unit output of rubber on the state farms is twice that on the plots planted by peasants. And, according to our research, the output of the state farms can be doubled again. Tropical plants are Hainan's treasures and rubber is the greatest of them all."

Hainan also produces more than 100,000 tons of sugar, 3,000 tons of tea, more than 1,000 tons of citronella oil and 20 million coconuts every year, as well as some animal and aquatic products. In 1983, the island's total agricultural output value was 1,896 million yuan, up more than seven fold from 1952. The island has more than 1,400 industrial enterprises producing sugar, salt, canned foods, rubber products, farm machinery, cement, electricity and mineral products and employing more than 100,000 people. In 1983, the island's total industrial output value reached 822 million yuan, up more than 19-fold from 1952.

There are scheduled flights from Haikou to Guangzhou and Zhanjiang. Shipping lanes link the island with all major ports on the mainland and in Southeast Asia. There are more than 14,000 kilometres of highways, up ll-fold from 1952. A post and telecommunications network links the island with the rest of the world. Social welfare facilities and living standards have also been greatly improved. Hainan has four institutions of higher learning, more than 500 middle and vocational schools, and nearly 5,200 primary schools. More than 95 per cent of school-age children attend classes. The island has more than 3,500 public health institutions, including about 460 hospitals with 18,600 beds, a 19-fold increase over 1952.

(To be continued)