Dormancy

• Dormancy is defined as physical or physiological condition of the seed that prevents germination in the presence of otherwise favorable conditions for germination
• Dormancy may occur within the embryo (groundnut) or in the seed coat (sunflower)
• The period of dormancy varies from a few days to several months depending on the plant species
• Quiescence is the phenomenon in which the seeds fail to germinate for want of a particular environmental factor.

Types of Dormancy

1. Primary dormancy

• This is also called as innate dormancy
• These seeds enter in to dormancy much before they harvested i.e. when they are still on their mother plant itself
• For instance:

2-3 months in Virginia runners of ground nuts

Up to 40 days after the seed is formed in sunflower

2. Secondary dormancy

• This is also called induced dormancy
• These seeds are dormant when they are harvested from the mother plant
• When they are exposed to brief periods of unfavorable environmental condition they show dormancy
• For instance:

Mustard seed exposed to high concentration of CO2

Wheat stored in high moisture content in air tight containers at 50 °C.