New Research in the Production of Seeds and Seedlings
In traditional Asian agriculture, farmers saved the seed from their own crops to use the followihng year. Now that most farnmers are producing for commercial production, they are buying seed of improved varieties. A good supply of reliable, high-quality seed is a basic need for the development of Asian farming. New technical developments are helping produce better seed at a lower cost.
Biotechnology
Tissue Culture
Tissue culture of vegetables and other crops has been carried out for twenty years. Scientists are still finding new ways in which this technology can be applied to Asian agriculture. One of the most important is in the production of disease-free seedlings. Plants infected by virus always suffer some loss of vigor. However, there may not be any visible symptoms in seedlings. Several Asian countries are using tissue culture to mass produce virus-free banana seedlings.
Tissue culture is also being used in Taiwan to produce large-numbers of disease-free medicinal plants. Many of these belong to species which are becoming rare in the wild. This program serves the double purpose of conserving rare plants, as well as providing farmers with new, high-value crops.
Dna Technology
DNA techniques using primers offer a new method of detecting viruses and other plant diseases. Although this method is very accurate, it is also costly. It is used mainly for high-value crops which are propagated vegetatively, such as orchids.
DNA fingerprinting can be used to characterize the genetic make-up of the crop. In the past, this could only be done by sowing the seed and describing the physical characteristics of the growing plants. This took time, and was not very accurate. DNA methods tell us the genetic characteristics of the plant much more accurately, using DNA extracted from the seed or young seedling. This is useful in a number of different ways. It helps plant breeders produce varieties which have the specific qualities which farmers and consumers are looking for. It also protects the intellectual property rights of plant breeders. Another useful function is in the maintenance of germplasm banks.
Purity and trueness of variety are very important for germplasm collections. DNA fingerprinting gives an accurate and detailed analysis of the genetic make-up of each accession. It can also be used to show whether genetic change is taking place over time. Seeds in germplasm collections must be repeatedly sown and harvested, so that the seed stays viable. In doing this, there is a danger that genetic drift will occur. While it is impossible to halt genetic drift completely, DNA methods allow us to detect whether it is taking place, and if so, ` to what extent.
The Dna-Tec Laboratory, Thailand
A major problem in using DNA technology is that the laboratory facilities needed are very expensive. At the FFTC Workshop, the participants showed great interest in Thailand's "DNA-TEC".
This is a service laboratory established by the Thai Government. It serves both public research stations and private commercial companies. For the first few years it had government support, but it is now financially self-supporting.
The DNA-TEC laboratory gives small seed companies and government plant breeders access to DNA technology, at a price they can afford. An important recommendation of the FFTC workshop was that this should be explored as a model for other countries in the region. FFTC and the sponsoring organizations were also asked to consider organizing training courses in molecular marker technologies.
Hybrid Seed
Hybrid seed makes use of the well-known trait of "hybrid vigor". This is a very important genetic trait. Hybrids of rice and other crops can be expected to give a yield 20-25% higher than ordinary varieties. In China, about 15 million hectares of paddy fields are now planted in hybrid rice. So are a growing number of rice paddies in Vietnam, India and the Philippines.
In the production of hybrid rice, a male sterile line is used. In conventional hybrid rice breeding, this generally involves a three-line system, using a sterile male line and two other lines. Recently a two-line system has been adopted in China. This uses a seed parent which is sterile in some environments, and fertile in others.
A major drawback of hybrid seed is that farmers cannot save seed from their own crop to plant the following year. Instead, they must purchase seed every year. Current research is developing vegetative propagation of hybrid rice for resource poor farmers, such as ratoon crops.
Hybrid seed is also labor intensive. To produce hybrid rice seed takes an extra 50 man-days per hectare. This is a disadvantage only in countries with a labor shortage. It could be seen as a benefit in countries where jobs are scarce in rural areas.
Transgenic Crops
Transgenic crops are still controversial, although the area planted in transgenic crops is increasing each year. In 1999, 43 million hectares of transgenic crops were grown in different countries of the world. More than three-quarters of these were grown in industrialized countries, particularly the United States. However, an increasing percentage are being planted in developing countries.
Whatever the advantages of transgenic crops, the technology of producing them will only be economically viable if there is market demand for the product. At the moment, consumer resistance to transgenic food crops is strong, especially in Europe. This in turn has limited the use of transgenic crops in Asia and the Pacific, particularly in food exporting nations such as Thailand. Whether consumer resistance will increase in time, or whether disappear, is difficult to predict. Most Asian countries are adopting a "wait-and-see" attitude, before deciding to invest a lot of money in transgenic crops.
Since transgenic crops are new, the long-term effect of consuming them is not yet known. In industrialized countries with a food surplus, consumers might reasonably ask why they need to take such a risk. They are likely to prefer crops bred by conventional means. It is a different situation in countries where there is a food shortage. Here, the greatest risk for many people is hunger. Transgenic crops may play an important role in relieving future food shortages, especially if the emphasis is on producing transgenic crops resistant to stresses such as saline soils, or common plant diseases.
Conclusion
Recent advances in seed production are making it possible to characterize seeds in detail, so varieties can be tailored to meet the specific needs of different environments and markets. Biotechnology offers improved methods of testing seed for quality, including purity, distinctiveness and uniformity, without having to plant the crop. It gives improved methods of identifying and eliminating pathogens. It has also helped bring improved agronomic performance, crop quality and yields.
However, Dr. Noel Mamicpic, Director of APSA, emphasized that in using biotechnology, researchers and entrepreneurs must consider smallholder farmers, and how they may share in the benefits of these new techniques.
"Don't forget", said Dr. Mamicpic, "that the ultimate beneficiary must be the farmer, who will produce all our food."
Index of Images
Figure 1 Tissue Culture of High-Value Plants: Callus Differentiating into Plantlets
Figure 2 Culture of Zantedeschia (Calla Lily)
Figure 3 Seed Tape with Radish Seed Allows Rapid Planting of Seeds at a Uniform Distance Apart
Figure 4 Pea Seeds. the Sprouts Will Be Harvested As a High-Value Vegetable
