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Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYSexual Reproduction in Flowering Plants4 Marks
Question
  1. How is artificial hybridisation considered a crop improvement programme?
  2. Explain the process of artificial hybridisation, if
  1. Female parent bears bisexual flowers.
  2. Female parent bears unisexual flowers.
✓

Answer

  1. Artificial hybridisation involves crossing of different varieties or species or even different genera to combine the desirable characters of the two parents to produce a commercially superior variety.
  2.  
  1. When the female parent bears bisexual flowers:
  • Emasculation is necessary; it is the removal of anthers/ stamens before the pollen grains mature.
  • The emasculated flower is bagged to prevent contamination of the stigma with unwanted pollen grains.
  • When the stigma attains receptivity, the pollen grains collected from the selected male parent are dusted on the stigma.
  • The flower is rebagged and allowed for further development.
  1. When the female parent bears unisexual flowers:
  • There is no need for emasculation.
  • The female flower is bagged before the stigma becomes receptive.
  • When the stigma becomes receptive, the pollen grains collected from the selected male parent are dusted on the stigma.
  • The flower is rebagged and allowed for further development.

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