Biotechnology to Produce Better Seeds and Seedlings
Training course on seedling science and technology
Use of Biotechnology for Conservation of Endangered Plants
Genetic diversity is the basis of plant breeding. Precious biodiversity is being lost with the disappearance of numerous wild plant species, mainly because of overexploitation and loss of habitat. Many wild plants have medicinal uses. They tend to become more valuable the scarcer they become. This encourages people to gather them to sell, and puts heavy pressure on surviving populations.
Tissue culture techniques are being widely used for the propagation and conservation of many traditional Chinese medical plants Fig. 1, Fig. 2. and Fig. 3. Some of them are becoming rare in the wild. The conservation of germplasm in vitro keeps these species safe from accidental extinction. The techniques also make available a large body of material for pharmacological studies and chemical analysis.
They also provide large quantities of disease-free seedlings for farmers. Tissue culture has made possible the mass production of disease-free and uniform plants. The technique thus brings farmers the great benefit of high-quality planting materials of new high-value crops
Finally, these same techniques can be used for the safe transfer of germplasm from one country to another. Many of the diseases and pests which damage agriculture today were introduced accidentally when new crop varieties were imported from overseas.
So much damage has already been done from these accidental invasions, that it is becoming difficult for countries to exchange plant materials. Many governments tend to feel that the possible damage from introductions may well outweigh any potential benefits. However, plant breeding programs need access to new germplasm.
Tissue culture offers a solution to the problem. Germplasm can cross international boundaries safely, in the assurance that no pests and diseases are secretly traveling with it.
New Methods of Disease Detection
In recent years, remarkable progress in molecular biology techniques has enabled scientists to acquire a more detailed understanding of plant pathogens. This training course introduced participants to current techniques of serological and molecular diagnostic techniques.
Serological assay is based on antibodies produced by animals, usually rabbit or rats. When suitable antibodies are available, the most sensitive and efficient test for plant virus is ELISA (=enzyme-linked immunosorbent assay). ELISA is widely used, since it is easy to apply and does not need any expensive equipment.
Another testing method is PCR (=polymerase chain reaction). PCR testing is very accurate, but it is also rather expensive and technically difficult. The participants were shown the preparation of samples for PCR testing, including the precautions needed to avoid the contamination of samples. They then practiced the steps themselves in laboratory exercises.
Dna Fingerprinting
The DNA composition of an individual plant is what determines its essential characteristics. The DNA fingerprint describes the DNA sequence profile of an individual. This is the same in every cell of that individual.
The DNA fingerprint cannot be altered by any change in the environment. Nor can it be changed by anything that happens to an individual during its lifetime.
Dna Markers
Different DNA markers are available, including RFLP (restriction fragment length polymorphism), RAPD (random amplified polymorphic DNA) and AFLP (amplified fragment length polymorphism).
These markers are used to characterize a variety or line, and in this way protect the intellectual property rights of the plant breeder. They are also used to evaluate the purity of seeds, and to detect genetic drift in germplasm collections.
It is also advisable to use the material for only five generations, or only five sub-culturing cycles.
International FFTC Training Course on Biotechnology of Seed and Seedling Production
Held at PCARRD, Philippines, on December 1-7
No. of countries participating: 10 (Bangladesh, Hong Kong, India, Japan, Korea, People's Republic of China,
Philippines, Taiwan ROC, Thailand, Vietnam)
No. of papers presented: 10
No. of participants: 25
Co-sponsors: Taiwan Agricultural Research Institute
Asia and Pacific Seed Association
Philippine Council for Agriculture, Forestry and Natural Resources Research and Development
Index of Images
Figure 1 Embryos Developing from Callus
Figure 2 Tissue Culture of C. Yanhusuo, Embryos with Shoots and Roots
Figure 3 Tissue Culture of C. Yanhusuo
