Fruit and vegetable consumption on Taiwan has increased rapidly in the last 30 years. Chinese on Taiwan consume an average of 169 kilograms of fresh fruits and vegetables per year, surpassing the American average of 168 kilograms.

Nevertheless, the Taiwan market is limited. An excess of any one type of fruit, for instance, may lead to a severe drop in prices which can be economically disastrous to fruit growers. Exporting is not a workable solution to this problem, as small-scale fruit growers from Taiwan cannot compete with large-scale, automated fruit production in developed western countries. Nor can Taiwan compete with many developing countries whose low wage rates make for low fruit prices. Processing is also unfeasible as a solution to excess fruit harvests. The expense of factory facilities and sanitation controls, along with local preferences for readily available fresh fruits would make processed fruits unprofitable.

With export and processing unfeasible, Taiwan's fruit-growers have chosen to develop higher quality, more highly profitable fruits for the local market. Pomology research has concentrated on lengthening harvesting seasons and developing new, tastier varieties. Thus, in recent years a number of new and improved fruits such as seedless grapes and huge Thai guavas have appeared in Taiwan's markets. In addition, many fruits previously available at only limited times of the year are now on the market almost all year round.

Summer fruit harvests are plentiful on Taiwan. To avoid an excess in supply, research has been carried out to adjust harvesting times and make summer fruits such as grapes, wax apples, star fruit and guavas available at other times of the year.

Such research is often based on practical experience and observation. For example, wax apple growers in southern Taiwan noticed that after a typhoon some of the wax apple trees whose stems and leaves had been broken off, and roots soaked, would grow new shoots that produced sweet, red fruit by winter. Realizing that this was a clue to adjusting harvest times, they sought the help of research organizations. They learned how while the typhoon had restricted the vegetative growth of the trees, this interference had in turn stimulated the trees' reproductive growth. Such stimulus can be artificially created to allow for the production of high quality wax apples from November to August.

Similar breakthroughs were made by the grape growers Yang Yu and Yang Ch'ao-sheng. Upon discovering late shoots that grew from vines whose branches had been accidentally broken off, they developed methods for a double grape harvest.

Fruit growers have also taken every opportunity to improve the quality of their fruits. Chang Jung-sheng's grafted pears are a good example. Two types of pears grow on Taiwan. Low altitude Hengshan pears are conveniently grown on flat land and have flexible harvesting seasons, but lack flavor and sweetness. The more expensive high altitude temperate pears must be grown in less accessible mountain regions but bear sweet, juicy, fine textured fruits. When Chang grafted branches from temperate pear trees onto Hengshan trees he found that he could grow an extra early harvest of fine, sweet pears. Harvests were also more plentiful due to cross-pollenization of the two varieties during grafting. While such grafting requires considerable labor and expense, profits from high quality, preseason fruits have provided ample compensation.

Other more universal techniques have been developed to improve fruit quality. Bag covers are used to protect fruit from birds and insects. Artificial plant foods now speed up the flowering process, promote successful grafting and induce seedless varieties.

Ou Hsi-k'un of the Taiwan Agriculture Research Institute developed a successful method for cultivating seedless Chufeng grapes. First he used a concentrated GA hormone to kill the plant's stamen and prevent pollenization and seed growth. Next, a thinned GA or 4-CPA hormone was used to incite fruit growth. The result was a successful seedless grape, only slightly smaller in size than the original variety.

All of these new methods are effective ways of temporarily altering the physiology of fruit trees and vines. At the same time they must be repeated every year, and require a considerable amount of labor. Thus, objectives are now focused on developing favorable hereditary characteristics in fruit. This is done by cross-breeding.

As many fruit trees require as many as six years to begin producing fruit, crossbreeding is a timely and often costly process. Some trees may resist cross-pol- lenization, and the quality of hybrids is difficult to predict. Difficulties are reduced however, by the use of vegetative propagation, in which branches and scions from one tree may be used to grow new trees in a shorter period of time.

Hsu Hsin-tz'u of the Taiwan Agriculture Research Institute has been able to speed up the growth of pear trees, which ordinarily begin bearing fruit seven to eight years after planting. By speeding up the germination process by planting seeds in a stratified preparation of sandy soil, Hsu has been able to cultivate trees which bear fruit only four years after planting.

Nevertheless, developing superior fruit varieties is a slow process which requires time, financial investment and determination. But despite the difficulties, limitless possibilities are open to the imagination. The imaginative researcher Chen Minhsiang, for instance, is developing methods of exposing guavas to radioactive rays which alter their chromosomes and cut seed numbers in half. Another method of altering chromosomes using the chemical colchicine has been used successfully in developing a seedless watermelon.

In the past few years Taiwan's fruit trees have suffered from toxic diseases. These are caused by viruses which attack the entire plant. Such viruses are carried by hardly insects which are difficult to control with pesticides, creating an important task for research.

One solution has been to find plant varieties that resist disease. The Ringspot Virus causes serious damage and spotting to papayas. At the Fengshan Tropical Horticultural Experiment Station, pomologists found a Florida papaya which resists damage by the virus. It is now being cross-bred with local varieties.

Another solution to plant disease caused by viruses is to simply cut down the trees and plant new ones. A quicker method, used for orange trees, is to clip off the infection-free shoot meristem of a diseased tree which at one time produced high quality fruit, but wasn't strong enough to resist the virus. The shoot meristem is then grafted onto the stock of another more durable, virus-resistant tree which did not previously produce quality fruit. Ten thousand healthy trees bearing sweet, juicy oranges will be cultivated in the next two years using this method.

The special fruits, large and healthy, sweet and seedless that appear year round in Taiwan's markets are the result of considerable research and experimentation. Because of the undying efforts of Taiwan's fruit growers and pomologists, we can now feast on huge, crisp guavas and seedless local grapes, or enjoy a sweet wax apple in the middle of October.

(Jill Ardourel)

[Picture Caption]

Because of Taiwan's temperate weather, fruits appear in the markets all tear round.

1. A Thai guava is three times the weight of the more common variety. 2. Restricting the vegetative growth of the wax apple tree by trimming leaves and branches will in turn stimulate reproductive growth. 3. Methods for double grape harvests were initiated in Taiwan. 4. Methods of growing vines along vertical bamboo stakes, more appropriate to mechanized grape cultivation, are being promoted in southern Taiwan. 5. The round fruit is a type of foreign papaya which is resistant to the Ringspot Virus. The oblong fruit is the common, local variety.

Fruit grower Chang Jung-sheng discovered that delicious temperate pears could be grown by grafting shoots of a temperate pear tree onto a Hengshan tree. 1-4. The grafting procedure involves trimming the shoot, using a special "safety knife" to cut a hole in the branch of a Hengshan tree, wrapping it with plastic tape, and protecting it with a plastic bag. 5,6. Once the shoot bears fruit, paper bags are used to protect it from insects. 7. An orchard of Hengshan trees awaits grafting of shoots from temperate pear trees.

1. Young trees cultivated by pomologists are protected in the greenhouse from insects. 2. A researcher looks after a number of grape varieties. 3. A seedless grape treated with growth stimulants (left), in comparison with a normal grape. 4. A farmer dips grape blossoms into an artificial growth stimulant solution and awaits a seedless harvest.

1. The variety of passion fruit now grown on Taiwan was developed by the Fengshan Tropical Horticultural Experiment Station. 2. Papaya and star fruit seedlings at a research station are protected by bag coverings. 3. Preparing for artificial cross-pollenization. 4. Researchers place their hopes on these tiny orange tree shoots.

1. A Thai guava is three times the weight of the more common variety.

2. Restricting the vegetative growth of the wax apple tree by trimming leaves and branches will in turn stimulate reproductive growth.

3. Methods for double grape harvests were initiated in Taiwan.

4. Methods of growing vines along vertical bamboo stakes, more appropriate to mechanized grape cultivation, are being promoted in southern Taiwan.

5. The round fruit is a type of foreign papaya which is resistant to the Ringspot Virus. The oblong fruit is the common, local variety.

Fruit grower Chang Jung-sheng discovered that delicious temperate pears could be grown by grafting shoots of a temperate pear tree onto a Hengshan tree. 1-4. The grafting procedure involves trimming the shoot, using a special "safety knife" to cut a hole in the branch of a Hengshan tree, wrapping it with plastic tape, and protecting it with a plastic bag.

Fruit grower Chang Jung-sheng discovered that delicious temperate pears could be grown by grafting shoots of a temperate pear tree onto a Hengshan tree. 1-4. The grafting procedure involves trimming the shoot, using a special "safety knife" to cut a hole in the branch of a Hengshan tree, wrapping it with plastic tape, and protecting it with a plastic bag.

Fruit grower Chang Jung-sheng discovered that delicious temperate pears could be grown by grafting shoots of a temperate pear tree onto a Hengshan tree. 1-4. The grafting procedure involves trimming the shoot, using a special "safety knife" to cut a hole in the branch of a Hengshan tree, wrapping it with plastic tape, and protecting it with a plastic bag.

Fruit grower Chang Jung-sheng discovered that delicious temperate pears could be grown by grafting shoots of a temperate pear tree onto a Hengshan tree. 1-4. The grafting procedure involves trimming the shoot, using a special "safety knife" to cut a hole in the branch of a Hengshan tree, wrapping it with plastic tape, and protecting it with a plastic bag.

5,6. Once the shoot bears fruit, paper bags are used to protect it from insects.

5,6. Once the shoot bears fruit, paper bags are used to protect it from insects.

7. An orchard of Hengshan trees awaits grafting of shoots from temperate pear trees.

1. Young trees cultivated by pomologists are protected in the greenhouse from insects.

2. A researcher looks after a number of grape varieties.

3. A seedless grape treated with growth stimulants （left）, in comparison with a normal grape.

4. A farmer dips grape blossoms into an artificial growth stimulant solution and awaits a seedless harvest.

1. The variety of passion fruit now grown on Taiwan was developed by the Fengshan Tropical Horticultural Experiment Station.

2. Papaya and star fruit seedlings at a research station are protected by bag coverings.

3. Preparing for artificial cross-pollenization.

4. Researchers place their hopes on these tiny orange tree shoots.