Origin of variation in purelines

Origin of variation in purelines

    1. Mechanical mixtures.
    2. Natural hybridization.
    3. Chromosomal aberrations.
    4. Natural mutation.
    5. Environmental factors.
  • A Pure line is the progeny of a single, self pollinated, homozygous plant. Development of new variety through identification and isolation of single best plant progeny is known as pure line selection.
  • All the individuals within a pure line have identical genotype any variation present within a pure line is solely due to environment. So Pure line is a large number of plants are selected from self pollinated crops and are harvested individually. Individual plant progenies from them are evaluated and the best progeny is released as a pure line variety.
    Characters
  • All the plants within a pure line have the same genotype. Because the parent plant was homozygous and self-fertilized.
  • The variation present within a pure line is environmental andnon heritable. So selection within pure line is not effective.
  • Pure lines become genetically variable with time. The genetic variation is produced by mechanical mixture, Natural hybridization or mutation.
  • Narrow adaptation, due to narrow genetic base.
Last modified: Tuesday, 13 March 2012, 7:39 AM