Describe in detail 'GM (genetically modified) crops' as an example of a current application of genetic engineering in the production of crops?

Crop refers to a large number of plants of any given kind
that are grown for human use.  Crops grown to produce food people and animals, fibres
for clothing for other use, raw material for medicines, and ornamental
material.

Genetic engineering has been used to produce new
varieties of crops that improve the crops in several ways like quality of the final
output produced, yield of farming, time required for harvesting, and adaptability to
different environment.

For thousands of years people across
the world have used breeding methods to produce favourable combinations of genes.  These
methods have produced most of the economically important varieties of flowers,
vegetables, grains, and animals.  In the 1970's and 1980's, scientists developed ways to
isolate individual genes and reintroduce them into cells or into plants, animals, or
other organisms.  Such techniques alter the heredity of the cells or
organisms.

Hundreds of genetically engineered plants have
been developed using such modern methods of genetic engineering. Some examples of
genetically modified crops are tomato plants to enable them to produce tomatoes with
increased flavour and shelf life; soybean, maize, and cotton plants resistant to
herbicides, plants to produce small amounts of a biodegradable plastic and plants to
produce material for potential use in medicines.