Botanical Name                                  :        Oryza sativa
Chromosome number [2n]                 :        24
Family                                                :        Poaceae
Inflorescence                                     :        Panicle
Pollination                                          :        Self-Pollination
Panicle Emergence                                       :        4 –5 days after boot leaf                                                                                        emergence
Flower Opening Pattern                      :       Tip of primary & secondary                                                                          branches and proceeds                                                                                downward                                
Duration of Flowering                         :        6-8 days
Time of Anthesis                                :        7.00 –10.00 A.M
Speciality with flowering                     :        Flower remain open for 10                                                                           minutes and afterwards it                                                                            closes.
Anther dehiscence                              :        Either before or after flower                                                                         opening [independent of                                                                                       spikelet opening]
Temperature favorable for flowering    :       24 -280C
Favourable RH for flowering                :        70-80%
Difference between day and
Night temperature                              :        8-100c
Stigma receptivity                              :        3 days
Pollen viability                                    :        10 minutes



Varietal seed production
Stages of seed production
In paddy depending on the demand 3 or 4 or 5 stages of seed multiplications are permitted under seed certification programme as follows.

  • Breeder seed - foundation seed - certified seed
  • Breeder seed - foundation seed stage 1- foundation seed stage 2 –certified seed
  • Breeder seed - foundation seed stage 1- foundation seed stage 2 -certified seed 1- certified seed 2

Land requirement
The land should be free of volunteer plants (crop of previous season occur in this season) and the same crop or the other varieties of the same crop should not have been grown for the previous season, if it is the same crop it (previous) should be the same variety that has been certified. This selection is highly important for maintenance of genetic purity. They should have adequate irrigation and drainage facilities and the problem soils are not suitable for seed production.

The crop should have 3meters of isolation at all sides of the seed production plot for maintenance of genetic purity.

Selection of seed
          Seed should be from an authenticated source (SAU, NSC, State Department).For production of certified seed, foundation seed  (FS) should be used as source seed which should be purchased with bill and tag (white for FS seed)

Seasons practiced at Tamil Nadu
In Tamil Nadu the availability of water in cannals, depends on the monsoon. Based on this in different districts, different sowing seasons are adapted as follows:

Month of sowing


Duration of varieties

December - January


Below 120 days

April – May


Below 120 days

April – May

Early kar

Below 120 days

May – June


Below 120 days

June – July


Below 120 days

July - August

Early samba

130 -135 days



130-135 & above 150 days

September – October

Late samba / thaladi / pishanam

130 - 135 days

November – October

Late thaladi

115 -120 days

November - October

Late pishanam

130 -135 days

Selection of season
          Season should be selected based on duration of the variety and the water availability.





Shout duration

November- December
(Karthikai –Margazhi)

Below 120 days

TKM9 ,CO 36,
ADT 36

Medium  duration

(Iyyppasi- Karthikai)

130-135 days

Bhavani ,CO43,

Long duration


More than 135

White Ponni,

Upland rice

July –August ---on receipt
of showers .TKM9 and
IR 50 should  be sown
Before 15th of July (direct seeding)

All durations but
variety specific

Co 43,IR 20

Rainfed rice

June-July and September –

Specific to

ADT 38 ADT39
(Medium Duration Varieties)

Seed Rate
It varies with varieties and type of cultivation.

Variety / type of cultivation

Seed rate

LOW LAND CULTIVATION  (transplanting)
Short duration varieties
Medium duration varieties
Long duration varieties


60 kg /ha
40kg /ha

For low   land cultivation by broadcasting

80-100 kg/ha

For rainfed rice

75-100 kg/ha

Seed Management Technique
Paddy exhibits dormancy which varies for duration of 0-30/45days depending on the variety. This could be broken by either soaking in KNO3 0.5 % for 16 hr or soaking in 0.1N HNO3 for 16 hrs. However the duration and concentration vary with varieties (e.g.) ADT36 exhibit 20-30 days of dormancy period from days to physiological maturity period which could be broken by soaking the seeds in 0.5%KNO3 for 16 hrs. Practically the intervening duration between the harvesting, and threshing, and further drying will remove the dormancy.



Seed Upgradation Technique (Egg Floatation Technique)
          Either before processing or after storage or due to improper processing  Paddy   seed   may have less vigorous seed such as immature, ill filled and insect damaged seed  which may adversely affect the planting value of the seed. Removal of this seed will favour  better establishment  and higher production potential.  These seed may be  removed   by adaptation of  a simple water floatation technique based on specific gravity  using salt water as a dissecting solution  for separation of good quality seed from low quality seed, and egg is used as an indicator for specification of specific gravity measurement of 1.03 (120g of salt in 1000ml of water)

A bucket of potable water has to be taken and in that water o fresh egg which sinks to the bottom has to be taken. To the potable water with egg outside slowly the common salt was added to a level at which the egg floats at top exposing 2.5 cm of its shell outside (check the egg floatation now and then on addition of salt to the solution). The egg is removed and the paddy seed are dropped into the solution which separates as sinker and floater .the sinkers are good seeds while the floaters are less vigorous and dead seeds. The floaters are removed and used as feed and sinkers are used for further multiplication.


  • Egg is only for measurement of specific gravity and has no work to do with separation.
  • If the density of water is more, more portion of egg will float if less egg will be inside the solution.
  • If the density of water is more loss of quality seed may occur ,lesser density the separation will not be perfect

Sprouting of seeds (pre germination)
Paddy seeds are sown at nursery in pre germinated condition for better establishment for supply of oxygen at waterlogged condition. Seeds are soaked in big tough  for 24 h in gunny bags  tied loosely for easy transmission of water and for ensuring soaking of each and every seed. Seeds are then tied tightly and incubated in dark for 12h (overnight). White protrusion of radices by the seed exposed to outside expresses the pre germination of seeds and these seeds are sown in nursery by broadcasting.

Hardening and other seed management techniques

  • In case of implementation of fortification treatment, seed could be soaked in equal volume of water to ensure that none of the solution is left unimbibied by the seed
  • For dry land and upland paddy, seed hardening with KCl (1%) and pelleting with Azospirillum (600g /ha) could be adopted (e.g.) MDU 1, Paramagudi1.
  • Seed colour variation occurs due to bacterial infection at later stages of maturation. Seed coloring with polycoat @3g kg-1of seed could improve the initial quality and marketability of such discolored seed.
  • Polymer coating of Seed also will help to identify the brand name of seed and to identify the varietal variation among the cultivars by even the illiterate labours.

Nursery Management
          For raising one hectare of paddy, 20 cent (800m2) nursery is needed. The area should be prepared by floating the area one or two days before ploughing and allowed the water to soak in. The soil should be kept at shallow sub emergence. Before ploughing the water should be allowed to a depth of 2.5cm .Then the land is ploughed and brought to a puddling condition. The optimum size of the nursery bed will be 2.5 meters broad and with channels of 30cm width in between. In paddy, on raising more varieties in a same place separate irrigation channels are to be prepared for each variety to avoid the admixture of seeds and to maintain the genetic purity.

Nutrient Management
Before the last puddling apply 40kg of DAP and if not readily available apply straight fertilizers@16 kg of urea and 120kg of super phosphate.
Basal application is required (DAP) if the seedlings are to be pulled out at 20 to 25 days after sowing. If the seedling are to be pulled out after 25 days application of DAP is done 10 days prior to pulling out of the seedling.
Basal application of phosphorus to the nursery enables the seedling to store phosphorus and utilize it even in later stages of growth and application of DAP to the nursery is highly economical.

          A thin film of water should be maintained in the nursery, and the sprouted seeds of paddy should be sown uniformly on the seed bed.







Water Management

    • Drain the water 18 to 24 hours after sowing and if there are pockets where water is stagnating, drain  it into the channel as germination will be affected in the places where the water is being stagnated
    • Allow the water to saturate the soil from the third to fifth day
    • From the fifth day onwards increase the quantity of water to a depth of 1.5 cm depending on the height of the seedling
    • Afterwards, maintain the water level to a depth of 2.5 cm

    Weed Management
              Apply any one of the pre emergence herbicides viz. butachlor 2l per ha,thiobencarb@2l/ ha, pendimithalin @ 2.5l/ha on 8th day after sowing to control weeds in the low land nursery. Keep a thin film of water and allow it to disappear. Avoid drainage of water. This will control germinating weeds.

    Pest Management (NURSERY)



    Army worm

     Spray Cholophyriphos 20EC 80ml or endosulphan
    35 EC80ml during the evening


    Phosphamidon85 WSC 25 ml(or)Monocrotophos 36
    WSC 40ml (or) Endopsulfan 35 EC 80 Ml

    Green leaf hopper

    As above or maintain 2.5 cm of water in the nursery and broadcastanyone of the following
    Carbofuran3g3.5kg or Phorate 10G1.0kg or Quinalphos 5g 2.0kg

    Case worm

    Mix kerosene in standing water and remove the cases and destroy and spray Monocrotophos 36 WSC 40ml (or) Quinalphos 25 EC 80 ml

     White tip nematode

    Sun drying of seeds for two days at 6h interval

    Rice root nematode

    Carbofuran3g at 3.5kg / 20cents



     Spray with insecticide Copper oxy chloride100g or
    Mancozeb 80 g

    Brown spot

    Carbendazim 40 g

    Tungro disease

    Aplly carbofuran 3g at the rate of 3.5 kg ten days after
    sowing or spray two rounds of Monocrotophos 36 WSC
    40ml or Phosphamidon 85 WSC 25 ml

    Age of transplanting
    The age of transplanting vary with varieties as follows



    Short duration varieties


    Medium duration varieties


    Long duration varieties


    Pulling out of seedling

    • Pull out the seedling at appropriate time
    • Do not remove the adhering soil with a hard surface
    • Tie the seedling in convenient size for easy handling
    • Do not allow the seedling to dry






    Main field preparation

      • Puddle the soil well
      • Apply 12.5tonnes of FYM or compost per ha
      • Incorporate green manure into the field by in situ ploughing
      • Dig the corners and prepare the bunds well with plastering for effective stagnation of water
      • Apply the phosphorus and potasic fertilizers at last ploughing for effective availability of nutrients to plants
      • Keep a thin film of water at the time of transplanting and  raise the water level to 2.5 cm  on the next day

      Fertilizer Requirement



      Nitrogen ( N )

      Phosphorus (P )

      Potash ( K)

      Short duration




      Long and medium duration





      Azolla  @ 1t/ha 3-5 days after weeding


      • Dip the root in phosphamidon 0.02 % against rice root nematode 20 minutes prior to planting
      • Plant the seedling at optimum spacing and optimum depth
      • Transplant the seedling at 4-5 leaf stage







      Details on transplanting


      Duration of cultivars




      No. of seedling per hill




      Depth of planting (cm)




      Spacing ( cm)

      20 x10

      20 x15

      20 x20

      No. of hills/m2




      seed multiplication

      Adopt double row planting with a spacing of 15 x 10 cm for easy  roughing

      - Adjust the sowing in such a way that harvesting does not coincide with rain

      Weed Management
      Pre emergence herbicide

       Use butachlor 2.5l/ha or thiobencarb 2.5l/ha fluchloralin2l/ha or pendimethalin3l/ha as pre emergence on third day and is to be followed by hand weeding on 30-35days. On the failure of pre emergence application, hand weed at 15 days and spray 24Dsodium salt with a high volume sprayer 3 weeks after transplanting when the weds are in3-4 leaf stage

      Gap Filling
      It is to be taken up between 7-10days after transplanting

      Pest and disease management


      Control measures

      Stem borer

      Fenthion100EC @  500ml

      Brown plant hopper
      Leaf folder
      Stemborer (white ear 2 %)

      Phosphamidon85 WSC @ 300ml
      MonocrotophosWSC @ 500ml
      Endosulfan 35EC  @ 60ml
      Quinalphos 25EC @ 1000ml

      Mealy bug
      Earhead bug

      Phosphamidon85 WSC @ 300ml
      Quinalphos 25EC @1000ml

      Rice root nematode

      Carbofuran3g 16.25kgin standing water



      Carbendazim @ 250g/ha

      Brown plant hopper

      Mancozeb @ 1000g/ha

      Sheath rot

      Carbendazim @ 250g/ha

      Sheath blight

      Difolatan @ 200

      Bacterial leaf blight

      Streptomycine Sulphate+Tetracycline@300g+Copper Oxychloride @ 1250g/Ha

      Grain discolouration


      Water Maintenance of Paddy

      • 5cm of water should be stand in the field. Normally once ion 2 days for loamy soils and once in 3 days for clay soils.
      • Excess water leads to yellowing of plant. So drain the water
      • The critical stages of irrigation are primordial initiation, booting,  heading   and flowering

      Top Dressing
      Apply 25% of N and k as basal and remaining 75 % in 3 split doses at active tillering, panicle initiation, and at heading stage in equal proportion of 1:1.

      Foliar Spray

      • Spray FeSO4 0.5% to prevent yellowing of plants in calcarious soils.
      • Spray DAP 2% to enhance seed set in paddy cultivars (BEST).
      • Spray GA3 three times at panicle initiation stage for complete exertion of panicle (hybrids).
      • Spray panchakavya 1% for organic seed production to enhance seed set.
      • Spray 0.5 % zinc sulphate thrice during crop growth on 20th 30th and 40th day of planting for short duration varieties or 30th 40th and 50th day for medium and long duration varieties in case of zinc deficient soils.


      • Is important to maintain for maintenance of genetic purity.
      • Remove all off types (deviant of the variety) and rouges (variant of the variety).
      • Remove when suspected is the thumb rule of roughing.
      • Rouging should be done from the sowing up to harvest and remove the as and when it come across.

      Physiological maturity

        • Seeds attain maturity with the visual symptom of turning of ear heads to golden yellow color and when the ear heads exhibit drooping symptomsi.e 28 days after 50% flowering in short and 31 days in medium and 35 in long duration.
        • When 80% of the plants are exhibiting the symptom the crop is ready for harvest
        • The moisture content of the seed will be 18-20-%.

      Pre-harvest Sanitation Spray
      Ten days prior to harvesting spray endosulphan 30EC 70ml / ha against storage pests. Spraying of 10 % prosopis leaf extract is recommended against grain discolouration.


      • Lodged plants should not be selected for seed purpose.
      • Withhold irrigation one week before harvest.
      • Delayed harvest may lead to heavy shattering
      • Bundled plants should be stacked as ear heads facing outside to avoid heat damage.
      • Threshed produce should be clean and free of admixture in cracks and crevices.
      • Birds scaring are also practiced in places of requirement.


      • Thresh the seed by beating the plants on a hard surface ,but take care that the seeds are not mechanically damaged.
      • In tractor and machine threshing avoid mechanical damage by proper adjustment of speed/machine setting.
      • Thresh at proper moisture content to avoid crushing / cracking (16-17 per cent).
      • Clean the floor, equipment, containers to avoid genetic and physical mixture.

      Winnowing and Drying
                Threshed produce are cleaned and winnowed to remove the dirt and other unwanted physical material.  Winnowing should be done in a cleaned surface. The seeds are dried in a threshing floor with adequate stirring which is known as tempering. The seeds are dried to 13 % moisture for better storage .On drying in a threshing avoid drying between 12 noon to 2pm to avoid the ill effects  of ultra violet rays of noon sun. Through not for bulk for prolonged storage this practice should be adopted. Seeds are also can be dried in mechanical driers in places of high humidity like areas of sea shore.

      The bulk seeds are normally processed through seed cleaner cum grader and the seeds of middle sieve are selected for seed purpose.

      Size of seed                                                                    Sieve size
      Long slender (Ponni, whitePonni)       = 1/16 x 3/4 " (1.3mm x 19 mm)
      Slender - IR 50                                  = 1/15 x 3/4"                 "
      Medium slender (IR 20, CO 43)                   = 1/14 x 3/4" (1.5 mm x 19 mm)
      Short bold (ADT 36, 37,38,39,
      TKM 9,Ponmani)                                 = 1/13 x 3/4" (1.8 mm x 19 mm)

      Seed Treatment
      Normally paddy seeds are not treated with chemicals owing to their economic utility. But for long term storage, treat it with captan or thiram or bavistin @ 2-4g / kg of seed, Halogen mixture treatment (Chlorine based halogen mixture @3 g /kg of seed) is a eco-friendly treatment. As a prophylactic measure seed can be fumigated with celphos @ 3-6g/m3.  But the moisture
      content of the seed should not be above 10-12% which may interfere with the seed quality in terms of germination.

      Seed Yield
      The yield of crop varies from 3000 to 7000 kg /ha depending on genotypes, location, season management practices and pest infestation.

      Paddy is a good storer. Generally paddy seeds store well up to 12-36 months depending on the genotypes but heavy infestation of storage pests reduce the storability of seed even to a month or two. For prolonged storage HDPE and polylined gunny bags are used, while for normal storage jute canvas bags are used. However the bags should not be stirred for more than 8 bags height to avoid pressure on seeds of lost bag which may cause damage to the seed. Polythene bags of 700 gauge is not highly preferable for paddy as the sharp edge may pierce the bag and convert moisture vapor proof container as moisture pervious container.

      Mid storage Correction
                Seeds from storage are given with mid storage correction when the seed standard reduce to 5-10% lesser than recommended. The seeds are soaked in double the volume of disodium phosphate solution (3.60g dissolved in 100l of water) for 16h and the seeds are dried back to original moisture content (12-13 percent).

      Seed Certification
      Land Requirement
      The previous crop should not be the same crop and if to be the same crop it has to be the same variety and should be certified and has to be accepted for certification. The field should not have any volunteer plants.


      Number of Inspections
                 A minimum of two inspections is needed, one at the time of flowering and another at the time of or before harvest.

      Field Standards
      General: Paddy field should be isolated from contaminants as follows


      Minimum distance(meters)

      Foundation stage

      Certified stage

      Fields of other varieties



      Fields of same variety not confirming to varietal purity requirements for certification



      Specific standard: These are verified at the final inspection


      Maximum permitted (%)

      Off types



      Objectionable weed plants*



                *Objectionable weeds are Wild rice (Oryza sativa L.var.fatua Prain (Syn.O.sativa L.f. spontanea Rosch.)

      Seed Standard


      Standards for each class



      Pure seed ( maximum)



      Inert matter (maximum)



      Huskless seed (maximum)



      Other crop seed (maximum)



      Other distinguishable varieties (maximum)



      Total weed seed (maximum)



      Objectionable weed seed (maximum )



      Seeds infected with paddy bunt
      (Neovossia horrida (Tak.) ( maximum)

      0.10% (By number)

      0.50% (By number)

      Germination ( Minimum)



      Moisture (maximum)



      For vapour proof containers (maximum)




      Paddy Bunt




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