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Learn Introductory plant breeding with Braimy- B.Sc agriculture
About Lesson
  1. Spontaneous :
  • chromosome doubling occurs occasionally in somatic tissues and unreduced gametes are produced in low frequencies.
  1. Production of adventitious buds :
  • Decapitation in some plants leads to callus development at the cut ends of the stem.
  • Such a callus has some polyploid cells and some of the shoot buds regenerated from the callus may be polyploid.
  • In Solanaceae 6-36% of adventitious buds are tetraploids.
  • The frequency of polyploid buds may be increased by the application of 1% IAA at the cut ends as it promotes callus development.
  1. Treatment with physical agents:
  • Heat or cold treatment centrifugation , x-ray or gamma ray irradiation may produce polyploids.
  • Exposing the plants or ears of maize to a temperature of 38-45 oC at the time of the first division of zygote produce 2-5 % tetraploid progeny.
  1. Regeneration in vitro:
  • polyploidy is a common feature of the cells cultured in-vitro.
  1. Colchicine treatment:
  • Colchicine treatment is the most effective and the most widely used treatment for chromosome doubling.
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