Conservation of Bio-Diversity in Seed-Banks, Gene-Banks or Germ Plasm Reserves

A large number of plant species form seed with variable periods of dormancy following which they can be germinated to yield daughter plants.

Most of such plants, therefore, can be preserved in the form of their seeds in small packets for long durations. Places where the seeds are stored are known as seed-banks or gene-banks or sometimes germ-plasm banks. The germ plasm of a plant is any of its living organ or a part of it from which new plants can be generated.

(1) Early Conservation Efforts:

In fact it was in response to the rapid erosion of genetic diversity among, pulses, cereals, fruits and vegetables, that serious efforts were started to conserve the genetic resources of crop plants early during the present century. After all, plants provide more than 90% of human food.

As early as in 1899 A.D., the Government of United States of America setup a separate section for collection, preservation and introduction of plants under its Department of Agriculture. In 1899 A.D., American Embassies all over the world were asked to collect and send samples of plants likely to be useful to the country. It was in 1947, that the Regional Plant Introduction station was setup at Ames, Iowa, USA. In 1959, the first Cold-storage centre for grains was established at Fort Collins, Colarado, USA. This centre is now one of the most important gene banks in the world for wheat, sorghum and soya.

Since 1920 A.D., Russian workers have also done pioneering work in the field of conservation of genetic resources of crop plants. It was V.I. Vavilov, a geneticist and agronomist, who observed a number of highly resistant wheat varieties when he was a student. Later as the director of the Leningrad Institute of Plant Industry, he sent out collection expeditions all over the world. It was through his efforts that the Russian germ-plasm bank has now become one of the biggest collections in the world. Following the Second World War, a number of seed banks, gene banks and germ plasm reserves have appeared all over the world.

Most of these efforts, so far, were concentrated on cereals, pulses and some plants producing tubers. Fruit trees were neglected altogether till the French Pomologist, from the Department of Ain, took the initiative in 1975. A census of available varieties of fruit trees was undertaken and about 280 threatened varieties of pear, plums, cherries and apples were multiplied on a 10 hectare plot.

These included many of the rare varieties of fruit trees which had almost disappeared from the market. The task of conservation of genetic resources of fruit trees goes on in France under the auspices of the Public Services Department and the National Research Institute. Similarly, plants like banana, coffee-H shrub and cocoa tree have been among the neglected lot.

Produce from these plants represent a major share of economy of a number of developing countries. It was on the initiative of some South St American countries that the first important collection centre for these plants was established in 1980 If at Napo Research Station, Ecuador, under the auspices of the National Institute of Agronomic Research. The centre has expanded its activities since then. However, much remains to be done in the I field of conservation of these and a number of tropical trees which provide valuable products to us.

(2) The Global Strategy:

For several decades, the efforts for conserving plant resources were taken up independently by developed countries alone. Developing countries were not even consulted. However, it was around 1960, that the rapid diminution of genetic diversity among crops of agronomic importance forced the advanced countries of the world to prepare plans for conservation of plant resources at global level.

The Food and Agriculture Organization (FAO) of the United Nations convened the first technical meeting for exploration, collection and conservation of plant resources of the world in 1961. The United Nations Conference on Human Environment convened in 1972 adopted a resolution concerning the International Programme for the preservation of genetic resources of plants cultivated in the tropical regions of the world.

Almost simultaneously a global strategy for preservation of seeds was developed at Beltsville, USA. The International Board for Plant Genetic Resources was framed in 1974 with its head quarters in Rome. By 1985, working on rather a modest budget it had setup a chain of 43 gene banks all over the world of which 21 are situated in I the developing countries. An International Gene-bank controlled by the Food and Agriculture Organization was also proposed in another conference of Food and Agriculture Department in November 1983. Some of the important centres for the preservation of plant resources around the world are:

1. Institute of Plant Industry, Leningrad, Russia for wheat, sorghum and barley.

2. National Seed Storage Centre, Fort Collins, Colarado, USA, for Sorghum, wheat and soya.

3. Plant Resources Conservation Centre, Beltsville, USA, for barley and wheat.

4. International Rice Research Institute, Philippines, for rice.

5. International Centre for Agricultural Research in Dry Areas, Aleppo, Syria, for wheat, peas, chick pea, beans and lentils.

6. International Centre for Improving maize, wheat and barley, Mexico.

7. International Crop Research Institute for Semi-arid Tropics, Hyderabad, India, for sorghum, ground nut, millets and chick pea.

8. Napo Research Centre, Ecuador, for cocoa, coffee and banana.

(3) Maintenance of Plant Germ Plasm for Long Durations:

Seed banks or gene banks earlier used simple techniques for preservation which involved storage of dried seeds under ambient or lower temperatures. General types of seeds such as those of many pulses, cereals, some vegetables and fruits possess natural dormancy and can be easily preserved for long durations by any of the following methods:

1. Short-Term Storage:

Seeds which are to be stored for a few years are sun dried and kept in sealed containers at a temperature of 5°C or even at room temperatures.

2. Mid-Term Storage:

Seeds which are to be stored for 15-20 years may be sun dried and maintained in sealed containers at temperatures between 0°-5°C. If these seeds are dried to about 4.5% of their moisture content, they can be maintained in viable state for longer durations.

3. Long-Term Storage:

If seeds are to be maintained for several decades or more they are previously dried to about 4.5% of moisture content and kept in sealed containers at temperatures between -10° to -20°C.

Some of these seeds, of tropical plants, bushes or fruit crops do not possess a natural dormancy. They die quickly if not allowed to germinate immediately. Little could be done to preserve these plants as simple techniques available at the time failed to preserve them. They had to be constantly cultivated. Similarly, a number of plants which reproduce by means of their vegetative parts such as tubers, corns, rhizomes etc. had to be regularly cultivated and multiplied.

Recent techniques of preservation have greatly extended the scope of germ plasm banks. Under liquid nitrogen which lowers the temperature to about -196°C, seeds dried to low moisture content can be preserved for almost indefinite periods – several hundred years or so. Through the application of tissue culture and cryo-preservation techniques almost any type of plant can be maintained in viable state for long durations.

Plants which cannot be preserved by traditional methods are preserved in the form of tissues or meristem cultures under liquid nitrogen. Small pieces of simple vegetative tissues or better still few meristematic cells of plants to be preserved are introduced in synthetic medium under asceptic conditions and are allowed to grow into small clumps – called the callus. These cultures or calluses are maintained under liquid nitrogen for any length of time. They can be multiplied and young plants differentiated from the tissues whenever required.

(4) Short Comings and Controversies:

Conservations efforts aimed at the preservation of germ-plasm of plants of agronomic importance suffer from the following basic short-comings and controversies:

1. Plant conservation activities involving seed collections and preservation usually revolve round few plant species of agronomic importance – plants which provide food to humans and his dependents. A large number of plants which are otherwise of known economic importance are ignored. It is obvious that we cannot provide refrigerated rooms for each and every plant. The procedure is costly and requires a lot of expert attention. Howsoever, efficient and versatile the approach may be, a number of agronomically important plants are expected to be left out.

2. At seed or germ-plasm storage centres a large number of plants are preserved in small packets or petridishes. Due to high costs it is not possible to maintain several of these centres. In the event of some unforeseen calamity or a War, the entire collection of rare plants may be destroyed. We shall be left with nothing if the plant variety or species is not available anywhere else. In fields or in natural habitats such disasters rarely happen.

3. Collection and preservation of germ plasm in seed or gene-banks tend to interrupt the vital process of evolution. The genetic organization of plants tends to stagnate. It is not only the preservation which is necessary but the adaptation and evolution of the plants to an ever changing environment is also important. Plants developed from seeds stored for long durations may entirely be misfit weaklings for by the time they are germinated the conditions of environment could have changed drastically. Thus a variety valued as resistant to a particular fungus may not be of any use as the fungus might have learned to over-come the resistance while the host plant has been lying dormant.

4. It is possible to improve the cultivated plants by using the desired genes from other varieties. Through genetic techniques these genes can be pooled together in a single cultivar which improves its commercial value enormously. Seeds or germs containing useful genes, therefore, acquire immense importance so also are the seed banks and germ plasm collections which possess a large assortment of varieties. Huge profits can be made by cornering the desired germ plasm and selling it at a high price to farmers and plant breeders.

The lure of huge profits has caused a number of big Multinational companies like Sandoz (Swiss), Imperial Chemical Industries (U.K.), Pfizer (USA), Ciba-Geiegy (Swiss), Up John (USA), to enter into the venture. Many of these multinationals have their own seed-banks with world-wide collections and elaborate facilities for conducting research in the field. These companies not only monopolise plant resources but also the techniques, know-how and innovations necessary to develop improved plant varieties. Huge sums are charged for providing the germ plasm and the necessary know-how by these companies.

The developing countries of the world, from where the desired germ-plasm might have originally come, are unable to obtain it or are asked to pay enormous sums of money for the resources of their own land. Many developing countries of the world have resented the establishment of these germ plasm banks and do not co-operate fully in the venture.

As almost two third of plant resources of the world happen to lie in developed countries the situation has resulted in a serious set-back to the conservation efforts for plants of agronomic importance. The matter has been taken up at the 22nd and 23rd sessions of FAO conferences but no consensus has so far been achieved as the advanced countries of the world are intent on protecting the interests of the multinational firms.