Rice

Seed Production

Seed Technology

Upgrading

Upgrade the seeds on weight basis before sowing by density grading using common salt solution having a specific gravity of 1.13 (1.5kg in 10 litres of water) and collect only the heavy seeds that sink at the bottom and rinse with water.

Seed hardening

  • Hardening rice seeds with 1% KCL solution prior to direct seeding under dry condition has been found useful to obtain normal yield under Cauvery delta region.
  • For this seeds are to be soaked in 1% potassium chloride solution (equal volume) for 20 hours.
  • After soaking, seeds are to be dried to original moisture content.

Breaking dormancy

  • Seeds may be soaked in 0.18 conc. Nitric acid (240 ml in 45 litres of water at 1:1 (equal volume) for 12-16 hours.
  • The seeds may be then air dried to original moisture content.

Seed treatment

Treat the seeds with panostine guazatine at 0.2% dissolved in ‘dichloromethane or with Cuman 1.0% dissolved in 20% PEG for 12 hours to control Helminthosporium oryzae internally borne. Air dry the seeds.

Spacing

Double row planting with spacing of 15 x 10 cm.

Manuring

Nitrogen at 100 kg, phosphorus at 50 kg and three levels of potash at 50, 75 and 100 kg/ha.

Harvesting

  • The earheads are to be harvested on attaining physiological maturity i.e. 28 and 31 days after 50% flowering respectively in short and medium duration varieties.
  • AT this stage 90% of the seeds will be straw coloured with 20% moisture content for medium and short duration varieties and 17% for long duration varieties.

Threshing

Threshing should be done at 16-17% moisture content.

Drying

Dry the seeds to reduce the moisture content at 16-17%.

Grading

Sieve size of 1.3 x 19 mm oblong perforations for fine seed varieties and 1.5 x 19 mm for medium and less coarse varieties and 1.8 x 19 mm for coarse seeded varieties are used to grade the seeds.

Seed treatment

  • Treat the seeds with Captan or Thiram 75% WDP at 4 g/kg of seed at 13% moisture for open storage and 9-10% for vapour proof storage.
  • Thiram or Captan is used to control the infection by Dreschslera oryzae, Sarocladium oryzae and Trichoconis padwickii upto 8 months in storage without affecting germination.

Container

  • For short term carry over use moisture free container like fresh grade bag or gunny bag.
  • For long term carry over use moisture proof 700 gauge polythene bag of PAFP bags.

Midstorage correction

Seeds from storage can be given hydration – dehydration treatment with disodium phosphate (3.60g / 100 litre) to improve the viability and vigour.


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