Course Content
Qualitative and quantitative characters (qualitative and quantitative characters in crops and their inheritance)
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Biometrical techniques in plant breeding (assessment of variability, aids to selection, choice of parents, crossing techniques, genotype-by- environment interactions)
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Selection in self-pollinated crops (progeny test, pureline theory, origin of variation, genetic advance, genetic gain)
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Hybridization techniques and its consequences (objectives, types, program, procedures, consequences)
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Genetic composition of cross-pollinated populations (Hardy-Weinberg law, equilibrium, mating systems)
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Breeding methods in self-pollinated crops (Mass, Pure line, Pedigree, Bulk, Backcross, etc)
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Learn Introductory Plant Breeding with Rahul
About Lesson

Undesirable effects

  1. Reduction in Diversity:
  • Plant breeding leads to reduction in diversity.
  • The uniform varieties are more prone to the new races of pathogen than land races which have high genetic diversity.
  1. Narrow genetic base:
  • Uniform varieties have narrow genetic base. Such varieties generally have poor adaptability.
  1. Danger of Uniformity:
  • Most of the improved varieties have some common parents in the pedigree which may cause danger of uniformity.
  1. Undesirable combinations:
  • Sometimes, plant breeding leads to undesirable combinations. The examples of man-made crops having undesirable combination of characters are Raphanobrassica and Pomato.
  1. Increased susceptibility to minor diseases and pests:
  • Due to emphasis on breeding for resistance to major diseases and insect pests often resulted in an increased susceptibility to minor diseases and pests.
  • These have gained importance and, in some cases, produced severe epidemics.
  • The epidemic caused by Botrytis cinerea (grey mold) in chickpea during 1980-82 Punjab, Haryana.
  • The severe infection by Karnal bunt (Tilletia sp.) on some wheat varieties, infestation of mealy bugs in Bt cotton.
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