Crop Improvement through Biotechnology

There are many stages involved in developing an improved crop. Farmers have been doing it for years through a more "natural way" called breeding. Limitations of this method included that it was random and "by luck", it required a lot of time and finally in most cases genes can only be transfered within a species.

In agriculture, farmers are concerned with insects that eat and destroy their crops, weeds that grow and damage their crops, frost, draught and viral diseases. As result of this, farmers use alot of herbicide and insecticide which solves some problems yet create other problems such as environmental pollution, leaving toxic residues which could harm us and non-specificity of the chemicals used. Farmers are also concerned with yield issues, how to get more bushels of corn, how to delay the ripening of tomatoes for shipment and many others.

A candidate gene therefore is identified by a group of scientist. These candidates are indentified either through a high thoughput screen or a screen for a certain trait. For example, hypothetically, a gene that is in a cactus which may be responsible for conferring the tolerence for heat may be a candidate gene.

These genes are then put into a vector which is usually first transformed into a model crop to test whether this gene will confer the heat tolerance expected. The transformation may be quite easy but it is difficult to get a " good event" this is when a candidate gene is inserted into an appropriate part of the model crop genome which allows it to express the protein at the same time not affect the other physiological processes of the plant. The model crop is then "assayed" this is a test to see if the trait is conferred. In this hypothetical case, it would be to see if the transgenic plant is able to withstand heat compared to the wild type plant (not transformed). Model crops are used because they are comparatively easier to transform to and they grow very fast and the results can be known within a few months.

Once it passes the model crop, it is then transferred to a commercial crop such as corn, wheat, soya bean, potato, tobacco, cotton and so forth. The commercial crop undergoes the same process and if a positive event is identified, the plant then undergoes manyh stages of thorough screening to ensure that nothing toxic to man or non-target organism is produced. It isi also checked for any alteration in the plant's metabolism and physiology and finally it is tested in the field for at least 3 years to see if it grows and behaves as normally as the wild type plant.

All through this, there is much paper work involved including documentation of the exact gene integration event and other safety guidelines to adhere to.