Chapter 20: Nuclear Energy: Applications – Food and Agriculture – Crop Improvement – Edited by Dr. Mir F. Ali

The generic alteration of plants to satisfy human needs is demarcated as crop improvement.  The common factors that are hampering crop production are abiotic, e.g. cold, salinity, soil aluminium toxicity and drought; as well as biotic, e.g. diseases and pests.  Modern Approaches like induced mutations and biotechnology offer new means and significant potential to breed desired varieties in a relatively short time.  Furthermore, these approaches facilitate the breeding of some vegetatively propagated crops which until now were improved mainly through selection of rare spontaneous mutants in natural or cultivated populations.

Induced Mutations (Successful nuclear techniques) designed to change the genetic makeup of a given plant variety without crossing with another variety.  With this approach, a variety retains all its original attributes but is upgraded in one or two changed characteristics.  This approach is based on radiation-induced genetic changes.  Scientific methods, mainly the use of radiation, can increase by a hundred thousand times the likelihood of beneficial changes in plants grown for man’s use, and provide a tool to break through present limitations in variability.  Already there are examples of better crops of wheat, barley, rice, oats, peanuts, soybean and other plants.

Here are the reasons to be seriously concerned about the current food situation generally and the food supply in particular:

• Immoderate continuing human population increases, most pronounced in some poor developing countries;
• The highly accelerated consumption of animal foods associated with increasing affluence in the richer countries of the world.  The production of such foods as meat demands great expenditures of grain, which is an inefficient mode of obtaining the required calories and protein for human consumption;
• The over-exploitation of many of the world’s fishery resources resulting in reduced yields, perhaps irreversibly, of some fishes;
• Recent price increases in petroleum and fertilizer products which have imposed a major obstacle to increasing crop production; and
• The apparent alteration of climates in places like Africa, Asia and other parts of the Northern hemisphere which may put significant restrictions on crop production.

Green plants are the ultimate source of resources required for human life, food, clothing, and energy requirements. Prehistoric people, who depended on their skills as hunters, drew upon abundant natural vegetation to collect nutritious and non-poisonous fruits, seeds, tubers, and other foods.  As human populations increased, greater and safer supplies of food had to be found, and gradually production systems based on plant domestication were developed.

The domestication of crops historically has been influenced by ecological and agricultural conditions, as well as by food gathering preferences.  Genotypes that have adapted to a wide range of climatic and edaphic conditions typically have been selected for cultivation.  The achievement of higher yielding crops facilitated population growth, sedentary settlements, and further development.  Which crops were domesticated depended not only on the number of seeds or the size of fruits, but also on taste, palatability, and other factors.  This process of domestication involved the identification of certain useful wild species combined with a process of selection that brought about changes in appearance, quality, and productivity.  The exact details of the process that altered the major crops are not fully understood, but it is clear that the genetic changes were enormous in many cases. In fact some crop plants have been so changed that for many of them, maize, for example, their origins are obscure, with no extant close wild relatives.

Page 1 of 5 | Next page