Mention two ways in which desirable …

Varieties or strains of crops can be selected by breeding for various useful characteristics such as disease resistance, response to fertilisers, product quality and high yields. Crop variety improvement is the manipulation of crop plants for increasing their yield and improving quality. Various approaches which are used for genetic improvement of crop plants are referred as plant breeding methods. These involve three processes:

(i) Introduction – This refers to the transportation of crop plants from the place of cultivation to the place where grown earlier.

(ii) Selection – This process involves the selection of most desirable offspring of a variety of plant for controlled propagation.

(iii) Hybridisation – It involves the crossing between genetically dissimilar plants to produce a new kind. Crossing may be between two different varieties (intervarietal cross - breeding) or between the two different species of the same genus (inter specific cross – breeding) and between different genera (intergeneric cross – breeding).