In nature dormancy terminates when
embryo gets suitable environment such as adequate moisture, aeration and
temperature. The impermeable seed coat present in
many species became permeable due to the rupturing of softening action of
natural agents like micro organism, high or low temperature, humidity fiber and
abrasion due to wind or digestive tracts of birds and animals which feed on
these seeds. Ex: Rhizoctonia damages seed coat
1. Seed coat treatments: These treatments aim at
making hard seed coat permeable to water or gases either cracking or softening
them. The process is usually referred as scarification. These
treatments are either physical or chemical in nature.
a. Scarification:
i. Acid scarification: treating seeds with concentrated acids like sulphuric acid,
Hydrochloric acid etc.
ii. Thermal scarification: the seeds are treated with different temperatures and gases
2. Embryo treatments:
a. Stratification: the incubation of seeds at a suitable low temperature
(Usually 0-50C) over a moist substratum
before transferring them to a temperature optimum for germination. Ex.
Cherry (Prunus cerasus), Mustard and rape seeds
b. High temperature treatment: in some species, incubation at 40-500C for few hours to 1-5
days may be effective in overcoming dormancy. Ex. Rice seeds more than 15% seed
moisture treated in hot water of 400C for 4-5 hours.
3. Chemical treatments: alternatively growth regulators or other chemicals may be
applied to induced germination growth regulators commonly used GA3 (100ppm),
kinetin (10-15ppm) and thio-urea (0.5-3%)
4. Miscellaneous approaches:
i.
Exposing seeds to light
ii.
Pressure treatment
iii.
Infra red radiation treatment
iv. Magnetic treatment
IMPORTANCE
OF SEED DOMARCY
1. Seed can survive for along time
2. Seed enable to maintain its food reserve for
long time
3. It enables the seed to survive under adverse
condition like drought
4. Enable the farmer to store seed for a long time