TOPIC: Seed Hardening, Principle and Its Use In Dry Lands Submitted To: Dr. K.B.SUNEETHA DEVI, PROFESSOR, Dept. Of .AGRONOMY. Submitted By: A.Ravi kumar, RAM/15-02.
SEED HARDENING Definition: The process of hydrating the seed to initiate the pre-germinating metabolism followed by dehydration which fixes the biochemical events. purpose: to impart resistance against stress conditions like drought and cold , to the emerging seedling
Water treatment: Seeds are soaked in water and allowed to absorb moisture up to 35 % of their weight and kept in swollen condition for about 6 hrs. at 15 to 25 o C . Then seeds are spread out in a thin layer under shade for 2 to 3 days to attain their original weight. The treatment can be repeated for 3-4 times, which depends on type of crops and their varieties . Methods of seed hardening:
Chemical treatment : The treatment of alternate wetting and drying of seeds as in case of water treatment have to be carried out with chemicals and varied concentrations.
Steps in seed hardening Dry seed S oaking in water or dilute solution of growth regulators and chemicals for 1-12 hrs at 15-25 c Shade drying Sun drying to bring back to its original water content Hardened seed
S oaking
D rying
Principle During hardening, a no. of physiological changes occur and modifies the protoplasmic character More absorption of water cause incease in elasticity of cell and development of efficient root system Dry seed Imbibition
Permits initial process of germination Shade and sun drying-original water content Stop the germination Hardened seed Sowing
Rapid germination and quick establishment of seedling Increase in growth and productivity
Materials and chemicals used for seed hardening Water Aqueous salt solutions like chlorides of Na, Ca, K, sulphates of Na, KNO 3 . Growth regulators like GA, kinetin, 2 chloroethyl phosphoric acid, ascorbic acid. Vitamins like B 3 , Nicotinic acid, pantothenic acid. Plant products like garlic extract, coconut water. Osmotic priming materials like D. Mannitol, PEP etc.
Recommended seed hardening practices in field crops under dry lands. Crop Chemicals rec’d Concentration (%) Hours of soaking Rice KCl 1 10 Sorghum Pot.Dihydrogen phosphate or KCl 2 6 Pearl millet KCl or NaCl 2 16 Finger millet CaCl 2 0.5 Until visibility of embryo growth Maize H 2 O - 12-16 Pigeon pea Zn (SO 4 ) 2 100 ppm 4
PULSES ( Green gram & Black gram): 4 kg of wood ash is collected , powdered. 30% Acacia gum is added and mixed thoroughly. 8kg of black gram or green gram seed is spread over paste . Sun dried for 5 hours and then sown before onset of monsoon.
Benefits It increases the speed of germination and germination percentage It increases the seedling vigour. The uniformity of seedling emergence. Increases the root growth. Flowering occurs 2-3 days earlier. Uniform seed set and maturity. Increases the yield.
L imitations Leguminous seeds less response to wetting and drying, over soaking –soaking injury. Prolonged soaking-accumilation of toxic substances. Chemicals should not give additional effects.
Role of Seed Hardening In Rice Variety Swarna Treatments: T-1:Control(non-hardened) T-2:Distilled water hardened T-3, T-4 &T-5:2, 3, 4 and 8ml Mg(No 3 ) 2 hardened
Treatments Grain yield kg/ha Harvest index N uptake P uptake K uptake control 856 34.1 16.5 7.8 25.9 Water 1037 32 21 10.5 31.4 Cacl 2 0.25% 1139 33 22.8 11.2 36.1 KH 2 p o 4 100ppm 1259 32.8 25.5 13.2 40.2 NaH 2 PO 4 100PPM 1331 33.5 26.9 13.8 41.7 Effect of seed hardening on crop productivity and nutrient uptake in finger millet .