With advancements in genetics, molecular biology and tissue culture, new traits have been incorporated into crop-plants.
Explain the main steps in breeding a new genetic variety of a crop. (5)
Main steps in breeding a new genetic variety of a crop.
(i) Collection of variability. The collection (of plants/seeds) having all the diverse alleles for all genes in a given crop is called germplasm collection. The germplasm is usually collected from wild relatives of the crop. The maximum genetic diversity of the particular crop can be found in places where the agriculture is still primitive and most of the wild relatives of the crop are still growing in wild habitats.
(ii) Evaluation and selection of parents. The germplasm is evaluated so as to identify plants with desirable combination of characters. The selected plants are multiplied. Pure lines obtained are used for hybridisation.
(iii) Cross hybridisation among the selected parents. The selected plants are crossed to combine the traits of both plants. For example, high protein quality, one parent and disease resistance from another parent may need to be combined in hybrid plant.
(iv) Selection and testing of superior recombinants. Selection of plants from the progeny of the hybrids, those plants have the desired characters. At this step in the process, we can get plants that are superior to both of the parents. Plants are then self-pollinated for several generations.
(v) Testing, release and commercialisation of new cultivators. The selected plants are then evaluated for their yield and other agronomic traits such as quality and disease resistance. They are grown in the research fields and their performance under ideal fertiliser application, irrigation and other conditions is recorded. Testing is done in research fields for atleast three growing seasons and then grown in different parts of the country. After thoroughly testing, the seeds of selected variety are recommended to the farmers for large scale cultivation. (5)