In animal husbandry, if two closely related animals are mated for a few generations, it results in loss of fertility and vigour. Why is this so?
The loss in fertility and vigour occurs after inbreeding because the recessive alleles tend to get together and express harmful effects in the progeny.
In the area of plant breeding, it is important not only to preserve the seeds of the variety being cultivated, but also to preserve all its wild relatives. Explain with a suitable example.
Collection and preservation of all the different wild varieties, species and relatives of the cultivated species is a important for effective exploitation of natural genes available in the population. e.g., sources of resistance genes may be cultivated varieties, germplasm collections of the crop or wild relatives.
Name a man-made cereal. Trace how it was developed and where is it used?
Triticale is a man-made cereal. It was developed by crossing Triticum aestivum (common wheat) and Secale cereale (European rye).
Triticale seed grain is being used in some parts of the world as a wheat substituted.
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A few statements are given below followed by a set of terms in a box. Pick the correct term and write it against the appropriate statement
| (a) | Mating of closely related individuals within the same breed. | (i) | Cross |
|---|---|---|---|
| (b) | Mating of animals of same breed but having no common ancestors on either side for 4-6 generations. | (ii) | Inter-specific |
| (c) | Mating of animals of two different species. | (iii) | Outbreeding |
| (d) | Breeding of animals belonging to different breeds. | (iv) | Outcrossing |
| (v) | Inbreeding |
(a) Mating of closely related individuals within the same breed is called inbreeding.
(b) Mating of animals of same breed but having no common ancestors on either side for 4-6 generations is called outbreeding.
(c) Mating of animals of two different species is called interspecific hybridisation.
(d) Breeding of animals belonging to different breeds is called cross-breeding.