Question

(a) Name the technology that has helped scientists to propagate the desired crops on a large scale in a short duration. List the steps carried out to propagate the crops by the said technique.
(b) How are somatic hybrids obtained?

Answer 1

Tissue culture is the technique that has helped scientists propagate the desired crops on a large scale in a short duration. Since a large number of plants are propagated through this culture, it is also referred to as micropropagation.

The following steps are carried out to propagate crops by tissue culture:

1. Explants are derived from any part of the plant to be propagated.
   
2. Explants are grown in sterile conditions in special nutrient media to regenerate complete plants.
   
3. The nutrientmedium must contain a carbon source (such as sucrose), organic salts, vitamins, amino acids and phytohormones (auxin and cytokinin)
   
4. All the plants obtained by tissue culture are called somaclones, since they are genetically identical to each other as well as to the parent plant.

(b) Somatic hybrids are obtained by the method of somatic hybridization. In this method, the somatic parts of two plants are hybridised. Protoplasts are isolated and fused to get a hybrid protoplast that grows further to form a new plant. For example, protoplasts of potato and tomato have been actually fused to form a pomato. But this plant is not commercially viable, as it does not have all the desired combination of characteristics for its commercial utilization.