The most potent biotechnological approach  now a days is the transfer of specifically constructed gene assemblies through various transformation techniques; this constitutes genetic engineering. The plants obtained through genetic engineering contain a gene or genes usually from an unrelated organism; such genes are called as transgenes & the plants containing transgenes are called as Transgenic plants. The first transgenic plant was produced in 1983, when a tobacco line expressing kanamycin resistance was produced. soon transgenic crop varieties resistant to herbicides, insects or viruses or expressing male sterility, Delayed ripening or slow fruit softening were developed. 'Flavr Savr' tomato was the first transgenic variety to reach the market; fruits of this variety remain afresh for a prolonged period. In 1996, The area under transgenic varieties was equal to 3 million hectares, which had increased to over 34 million hectares by 1998( a 12 fold increase) in merely 2 years.

1. They have proved to be extremely valuable tools in studies on plant molecular biology, Regulation of gene action, Identification of regulatory/ promotory sequences etc.
2. Specific genes have been transferred into plants to improve their agronomic & other features. Genes conferring resistance to abiotic stresses e.g. herbicides, have been transferred in crop plants, Which enables the use of biodegradable herbicides like glyophosphate in otherwise susceptible crops.
3. Genes for resistance to various biotic stresses have been engineered to generate transgenic plants resistant insects, viruses etc.
4. Several gene transfers have been aimed at improving the crop quality, e.g. protein or lipid quality etc of transgenic plants; efforts have been made with a variable degree of success. Improved quality may also be obtained by either suppression of or overproduction of endogenous genes.