ABSTRACT
Ever since the dawn of civilization, man has depended on plants as a source of food and feed. Dramatic improvements in crop yield were obtained in the previous century as a result of intensified use of land, fertilizers and pesticides and by planting improved varieties developed through different plant-breeding techniques based on genetic principles. However, there are indications that "The Green Revolution" is slowing down and there is an urgent need to have a "Gene revolution" to meet the increase in demand for food. In future, major increases in cropped area are unlikely. Pesticide use is on the decline due to increasing concerns about their harmful effects on the environment and human health. Hence, it is essential to produce more food from less land with lesser pesticides, lesser labour and lesser water. Of the different strategies for increasing crop productivity, one of them is to genetically engineer plants so as to
increase their productivity. In order to apply genetic engineering techniques for crop improvement, one should be able to identify and isolate the agronomically-useful genes, modify them according to the requirements, transfer them into cells/tissues and ultimately recover them in mature transgenic plants that can be used in breeding programmes. Genes for production of transgenic plants can be accessed from diverse sources such as plants, bacteria, animals, fungi or viruses. Targets for genetic transformation will include:
Resistance to herbicides Resistance to diseases and pests Improving protein content Changing oil quality
The genes to be introduced have to be specifically modified for expression in specific tissues /organs at particular stages of plant development.
