Introduction to Genetic Variation-Urdu-Hindi By Dr Rashid M Rana

Genetic Variability - The basis of plant breeding
Genetic variation: Variation in alleles of genes, occurs both within and among populations.
 The variation that results from genetic causes and transmitted from parents to progeny.
Importance: Genetic variation is important because it provides the “raw material” for crop improvement.
Types: (i) Variation due to environment; variation in size, shape, colour or composition due to environment e.g. variation in population due to differences in soil fertility, or photoperiod etc.
 (ii) Hereditary variation; variation in size, shape, colour or composition due to heritable causes and transmitted to next progeny.
 The variation that results from genetic causes and is transmitted from parents to progeny is termed as hereditary or genetic variation.
 These may be simple and easily observed e.g. flower or seed colour, pubescence on leaf or stem, presence or absence of awn in grasses, resistance to disease pathogen.
 These may be complex (polygenic): vigor of plant, plant height and yield.
 The extent of genetic variation for a particular trait of any genotype is referred to as genetic variability which is used in all the breeding programmes.
 As without genetic variation it is meaningless to think of any crop improvement. Hence genetic variability is the basis of any plant breeding programme.
Origin
Sources of heritable variation
Heritable variation in plant originate
1. Plant Introduction
2. Gene recombination as a result of outcrossing/chance or artificial hybridization
3. Changes in chromosome number and structure
4. Spontaneous and induced variation (mutation)
5. Genetic Engineering
6. Soma Clonal variation
The plant species have evolved in nature through above mentioned factors and reached the present stage of development. Plant breeders isolate the plant types that fulfill their needs by selection from genetically mixed populations of a plant species or they may employ the above forces to create new populations.

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very good sir.

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How can a plant breeder create genetic variation by artificial means? Support your answer with examples

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By artificial selection

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Or hybridization

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Sorry