During the last decade, tremendous progress has been made in the area of genetic engineering towards agriculture. Recombinant DNA technology has opened up new opportunities for highly specific manipulation of the genetic material. Once applied and developed to a sufficient degree, it promises ultimately to provide a powerful additional tool to the plant breeders. This technology broadens the possibilities of transferring genes between unrelated organisms and creating novel genetic information by specific alternation of cloned genes.
Application of genetic engineering in field of agriculture is:
a. Creation of resistance varieties of plants: Transfer of specific genes from one species to another may be of great significance in exploiting diseases, insects and pest resistance mechanisms more efficiently. Various genes responsible for resistance to diseases have been identified, cloned and incorporated or manipulated into another species. For example, Bacillus Thuringiensis is a bacterium that has ability to destroy stem borer pest in rice and maize. Keeping this view in mind, scientists isolated BT gene from a bacterium Bacillus thuringiensis and cloned and then incorporated it into rice or maize genome.
As a result rice or maize shows the resistance against stem-borer due to presence of Bt gene in rice genome. Various novel plants with resistance to various diseases pests and stresses have been created using recombinant DNA technique.
b. Bio-fertilization: Molecular nitrogen in the atmosphere is converted into biologically usable form by nitrogen fixing micro-organisms e.g. Rhizobium. The most sophisticated approach to bio-fertilization is to create plants that possess genetic capacity for nitrogen fixation. Attempts are being made to transfer genes for nitrogen fixation gene called nif gene from bacteria to rice or other non-leguminous crops.
c. Increase the protein content: One of the major source of protein for human and animals consumption is constituted by the proteins contained in seeds of many plant species. The cereals and legumes which are major sources of storage proteins contain limited amount of certain amino acids which are essentials for human beings. Majorities of these cereals are deficient in lysine whereas legumes are deficient in sulphur amino acids. The genes which code for a number of storage proteins have been cloned. For example, the gene encoding the French bean protein, phaseolein, has been expressed in sunflower.
d. Creation of transgenic animals: Animals that have foreign genes inserted into their germ lines are called transgenic. They can pass the gene on to their offspring, and it can be inherited as a Mendalian trait.
