Seed Dormancy



• Time of development to germination - Inactive stage of embryo

• Failure of viable embryo to germinate is called dormancy

• External Dormancy: lack of moisture, High Temp, Oxygen

• Internal Dormancy:

– Condition within embryo (Embryo Dormancy)

– Influence of Hard Seed coat ( Seed coat Dormancy)

– Substances in seed or fruit chemically inhibit (Inhibitory Dormancy)

Embryo Dormancy

• Freshly harvested seed required some period of dry storage before germination

• Change in storage is called After ripening, after certain period of rest, seed can be used.

Seed coat Dormancy

• Impermeability of seed coat to water

• Decomposition of seed coat: moisture & warm temperature

• Supply of Nitrates effects seed coat softening

• Membranous seed coat layer restrict transfer of gas

Inhibiteroy Dormancy

• Small portion of endosperm in contact with embryo prevents germination Pre germination treatment to break the dormancy

• Soaking: Soaking period depends on hardness of seed coat (Guava)

• Scalding: immersed in Hot boiling water and allowed to soak in the gradually cooling water for 12-24 hrs

• Mechanical: Rubbing the seeds in folds of sand paper (Chiku, Canna & Ber)

• Stratification: Alternate layers of soil & moist sand at 32 o F to 45 o F for 1 to 4 months (Apple, Pear & Cheery)

• Scarification (Chemical): 25 to 50 % H2SO4 treatment is given to seed

Seed Sowing

• Seeds are sown in raised beds, pots, poly bags, etc

• Soil solarisation is done. Adding FYM + Sand, Ideal potting mixture is developed.

• Seeds are sown 7 mm to 1.25 cm deep in rows 10 cm apart

• Normally seed requires 3 to 4 weeks for germination in majority of crops.