Scientists and agribusinesses can propagate plants by cloning them in tissue culture. This type of asexual propagation is also called micropropagation. Micropropagation is a popular technique that has both advantages and disadvantages.
In micropropagation, small pieces of tissue cut from the parent plant are grown on an artificial medium in a petri dish. The medium contains all the nutrients the plant cells need to thrive. Detached from the parent plant, the cells on the medium divide to form a lump of tissue called a callus; the callus will later differentiate to form a plantlet. The micropropagation technique can rapidly produce large numbers of individuals that are genetically identical to the parent.
If an individual plant has highly desirable traits, micropropagation can create a large number of clones that all share the same characteristics. For example, if a particular flower has a certain shade of colour breeders find appealing, they can clone the plant to create many individuals that share this particular feature. Cloning in tissue culture is also fundamental to genetic engineering techniques, since typically these must be performed in culture.
Cloning in tissue culture doesn't introduce any new genes into the gene pool and can pass on undesirable traits. If a plant is unusually susceptible to disease, for example, and the plant is cloned in tissue culture, all of the clones will share this undesirable feature found in their parent plant. Crop breeding, by contrast, creates individuals that have genes from two parents rather than only one.