Growth and Development of Horticultural Crops (1+1)

Definition-Vernalization

• Certain plants require a low temperature treatment during their earlier stages of the life history for subsequent flowering in their later stages.
  
• This was first realized by Klippart in 1857 when he found that winter wheat could be converted to spring wheat if the seeds after slight germination were kept at nearly freezing temperature (0-5 C).
  
• This conversion by low temperature treatment or chilling treatment was termed as vernalization by Lysenko (1928). Due to this, vegetative period is cut short resulting in early flowering.
  
• The effect of cold stimulus on plant is not immediately visible. It is expressed only at a certain later stage in the form of flowering.
  
• Thus like the photoperiodism, the phenomenon of vernalization is an excellent example of the physiological preconditioning.

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