Seed :: Cereals & Millets :: Pearl Millet

QUALITY SEED PRODUCTION IN PEARLMILLET VARIETIES

Field selection for seed production

The land for seed production should have good drainage facility. Because, pearlmillet plants do not withstand stagnation. The previous crop should not be of pearlmillet. If the previous crop is pearlmillet, then it should be of the same variety. Keeping these points in mind, the field should be selected to avoid genetic contamination caused by volunteer plants.

What are volunteer plants?
     
Volunteer plants are those that grow in the field from the seeds found in the soil. These seeds should have been fallen from previous season crop. Since they germinate without sowing or they volunteer to grow by themselves, hence the name volunteer plants.

Isolation distance for maintaining genetic purity
           
Cross pollination in pearlmillet is around 64-85 per cent. To maintain genetic purity, the field should be isolated alteast by 200 m for certified seed and 400 m for foundation seed from the fields grown with other varieties. By adopting this isolation distance pollination by foreign pollen can be avoided and maintain the genetic purity of seeds.

Season for seed production
           
Season is important for seed crop. Season of production influences the quality of seeds being produced. Being a drought resistant crop, dry weather is more suitable for pearlmillet seed production. Rain during panicle emergence and flowering will adversely affect the seed set and also it leads to ergot (sugary) disease incidence. For quality pearlmillet seed production, winter season (October – December) is the best.

Nursery formation and vigorous seedling production methods
           
Selection of nursery is very important to get good and healthy seedlings. By sowing good quality seeds with high germination potential and vigour, vigorous seedlings can be obtained.

Selection of nursery area and fertilization
           
The previous crop should not be pearlmillet in order to avoid rogue plants. If the previous crop in the field happens to be pearlmillet, irrigate, let the buried seeds to germinate and plough after one week. By this method, the off type seedlings are destroyed, avoided contamination and reduced the cost required to remove the rogues in the main field.

Land selection
           
Nursery land should be fertile with good drainage facility. It should also have good water source for irrigation.

Area for nursery
           
An area of 300 m2 is necessary to produce seedlings for one acre. The land should be ploughed three times and during the last plough, 750 kg of well decomposed farm yard manure should be applied.

Raised bed formation
           
For each 40 m2 nursery area; six beds of the size 3 x 12 m with a height of 15 cm should be formed. Each bed should be surrounded by a channel of 15 cm width and 7.5 cm depth.

Seed selection and its advantages
           
To get vigorous seedlings quality seeds are to be sown because weeding, fertilization and irrigation will give the required dividends only if the plant population is optimum. The vigour of aged seeds is low and so it can not produce vigourous seedlings. Seeds infected by pathogens will not germinate or will produce diseased seedlings. So, vigorous and disease free seeds are to be selected.

Elimination of pathogen infected seeds
           
During seed maturation, cumbu may be infected by ergot disease, which is internally seed borne and passes the disease to next generation crop. Such infected seeds have to be eliminated. The infected seeds can be eliminated by salt water floatation method.

Seed separation using salt water
           
In a bucket of 15 litre capacity, take 10 litre of pure water. In this, dissolve 2 kg of salt. This is only the common salt used for cooking purpose. Stir the solution thoroughly till the salt dissolves fully.
           
In this solution, add the seeds and stir. Good quality seeds will settle down in the bottom of the bucket. The immature and infected seeds will float over the solution. The floaters must be removed. The sinkers can be used for sowing. But the sinkers cannot be used as such for sowing. Removing the salt over the seed surface is necessary. For this, the sinkers should be washed with water for 3 to 4 times. By this method, salt deposited over the surface of seeds is washed off. After shade drying of the seeds mix 600 g Azospirillum with 4 kg seeds.

Seed rate
           
To plant one ha of land, 3-4 kg of seed is necessary. For the production of certified seeds, use foundation seeds for sowing.

Sowing
           
Sow the graded and treated seeds over the raised beds.

How to sow?
          
In the raised beds, make 1 cm deep furrows using a stick or with fingers. Spacing of 15 cm must be maintained between 2 furrows. Sow the seeds in these furrows and cover with soil. Apply 200 kg of well decomposed farm yard manure over the furrows and spread it equally over the raised beds.

Seedling protection in the nursery
           
To protect the seedling, apply insecticides and fungicides based on needs. For the tender seedlings, insecticides with high concentration should not be used. Carbofuran 3% granule (750 g) should be mixed with 5 kg of moist sand applied equally over all the nursery beds. By this method, the seedlings can be protected from stem borer. If any insect attack is noticed, spray 5 ml of Methyl Demeton or Dimethoate in 2.5 lit water on 7th and 14th day.

Irrigation
           
Provide one opening for 6 raised beds openings. After ensuring enough water, stop the irrigation.

Attention

There should not be any soil cracks on the nursery bed. If seen, provide irrigation

Age of seedlings
           
Age of seedlings is one of the important factors in deciding the growth of seed crop and yield. Transplanting of too young or too old seedlings will adversely affect the yield. Eighteen day old seedlings are appropriate for transplanting. Avoid aged seedlings for transplantation.

Main field preparation and transplantation
           
In the selected land, spread 12.5 tonnes of FYM per ha before ploughing. After applying FYM, plough the land to mix FYM with the soil. Then apply 2 kg of Azospirillum per ha of land.

Ridge formation
           
Form the ridges with a length of 6 m and spacing of 45 cm between them. For CO 7 variety 40 cm distance is enough. We can alter the distance between the ridges   based on the variety.

Fertilizer application
           
Fertilizer should be applied at the bottom and on the same side of the ridge on which the seedlings will be transplanted. 325 kg urea, 525 kg super phosphate and 150 kg of potash should be applied to the fields in which azospirillum had been applied already. In case of non application of azospirillum, the fertilizer dose should be 375 kg urea, 525 kg super phosphate and 150 kg potash per ha as basal application.

Micronutrient application
           
Micronutrient application is very important for the growing plant. Micronutrient   mixture (12.5 kg) can be mixed with 50 kg of sand and applied to one ha of land before transplantation. If the micronutrient mixture is not available, apply the specific micronutrient deficient in soil.

Handling of seedling
           
Fifteen to 18 day old seedlings should be removed from the nursery without any damage to roots. The roots of the seedlings may be dipped in Azospirillum solution before transplanting.

Preparation of biofertilizer solution
           
Mix one kg of Azospirillum in 40 litre of water. Dip the roots of the seedlings in this solution for 15-30 minutes before transplantation.

Transplanting
           
Biofertilizer pretreated seedlings should be planted on the sides of ridges with 20 cm distance. By maintaining appropriate spacing, adequate plant population stand and high yield can be obtained.

Irrigation Management
           
Though irrigation management is not different for this crop, irrigate the field in the following critical period:
            After transplantation                  1 to 18 days
            Panicle initiation stage   19 to 35 days
            Flowering stage                        36 to 55 days
            Maturation stage                       56 to 85 days
In the above mentioned stages, there should be enough moisture in the field

Attention
     
Irrigation depends on field condition. Hence, you have to alter the irrigation schedule based on field condition.

Weed control
          
It is very important to control the weeds from the initial stages in the seed crop. For this, herbicide Atrazine 1250 g can be applied on 3rd day after transplantation by using hand sprayer. One hand weeding should be done at 30-35 days after sowing.

Top dressing
           
Urea at 300 kg should be applied per ha as top dressing at 15 days after transplanting for the seed crop. Immediately after top dressing, irrigation is essential. 

Crop protection
           
Protection against pest and disease is very important for seed crop. Hence, to control the pests and diseases, follow the recommended control measures as and when necessary.

Roguing
           
Providing isolation distance is important  in order to maintain the genetic purity. Rogues are the plants having very obvious morphological difference and off type plants posses minor and subtle differences compared to variety. If pollen from these plants fertilize normal plants, resultant seeds will show genetic varieties. Seeds set on these plants will also be genetically different. Hence, rouging of those plants from the seed field is necessary to maintain genetic purity.

Guidelines for roguing

Crop Stage

Rogues to be removed

Before flowering stage

Plants differing in height, leaf size and colour and stem colour

Flowering stage

Early flowering and late flowering plants

Before harvesting stage

Ergot disease infected plants and plants with deviant morphological features

After harvesting stage

Based on size, colour and shape, remove the offtype panicles.

Harvesting and threshing

Stage of harvest
           
Harvest the crop at appropriate stage. Otherwise, the whole of efforts made for raising the seed will go in vain. Seeds harvested before full maturity will shrivel and become small during dying thereby affecting the germination capacity. If the harvest is delayed, seeds may be damaged by pests and diseases leading to discolouration and seeds may also shed.
           
Eighty to ninety five days is optimum period for harvest. At this stage, the leaves get dried and the plant itself looks like dried one. The seeds are hard and the moisture content of the seed will be around 20-25%.

Threshing and drying
           
During threshing, the moisture content of the seed must be around 15 to 18%. At this moisture content, there will be less mechanical damage and seed injury. If the moisture content is more or less than 15 to 18% during threshing, seed injury will occur. At high moisture, the seed injury leads to fast deterioration of seed quality favouring fungal infection.

Drying
           
Threshed seeds should be dried immediately, otherwise it leads to decline in germination capacity. Reduce the moisture content upto 10%. The seeds should be dried under the sun between 8 a.m. to 12 noon and then 3 p.m. to 5. p.m.

Seed processing

Attention

During seed grading, the sieves are to be cleaned thoroughly before use. Otherwise it may leads to contamination with other variety seeds.

Seed Yield
           
Seed yield of 2000 kg ha-1 can be obtained.

Seed storage practices
           
Seed storage is very important to keep the seeds with good quality upto next sowing season.

Seed moisture content
           
If seed moisture content is high, the seeds will loose germination capacity early. Bring down the moisture content below 12% before storage. For long term storage, store the seeds in moisture vapour proof polythene containers at 8% moisture. Seeds with 10% moisture can be stored in polylined cloth bags.

Seed treatment
           
Dry the seeds upto 12% moisture content and treat with Captan or Thiram 75% wettable powder at 70 g in 500 ml water for 100 kg seeds. The treated seeds can be stored for a year in cloth bag containers. The seeds with 8% moisture trated and packed in moisture vapour proof containers can be stored for one and half years. Eco friendly and non-toxic chemicals can be used for seed treatments. Use of non-toxic chemical helps in controlling the environmental pollution besides being safe to the women laborers engaged in seed treatment. Treat the seeds with halogen mixture at the rate of 4 g per kg of seeds. Calcium oxychloride + calcium carbonate + Albizia amara leaf powder are mixed in the ratio of 5:4:1 and stored in an air-proof container for a week to prepare the halogen mixture.

Storage
           
Seeds have the tendency to absorb moisture from the surrounding atmosphere. Use moisture vapour proof containers like polythene bag of 700 gauge thickness in the areas where the moisture content in the atmospheric is high. For moisture vapour proof container, the seed moisture content must be 8% or less. Seeds can be stored in polylined cloth bag at 10% moisture content. Avoid keeping the bags directly on the floor and near the walls. Keep the bags over the wooden pallets, so that the absorption of moisture by the seed from the floor and walls is prevented.          

Keep only 6 to 7 bags in a stack. If the number of bags are more, it will excert pressure to the seeds in the basal bags leading to the loss of germination capacity.

Seed certification
           
Seed certification guarantees the quality of seed as it ensures that the certified seed has the genetic, physical, physiological and seed health qualities.  Genetic purity means that the seed gives rise to a plant which conforms to the varietal characteristics of the variety. The physical purity means that the seed is free from stones, broken seeds, straw bits and leaf bits etc. Physiological quality is measured by germination and seed health envisages freedom from pest and diseases.
           
Seed certification is being done in many stages. It starts from verifying whether seeds were obtained from authenticated source, verification of isolation distance and inspection during plant growth, flowering, harvesting, processing and bagging. Also seed samples are drawn form the seed lot and sent to seed testing lab to test whether the seeds are possessing required physical purity and germination. Then certification tag is issued. Colour of the tag is blue for certified seeds.
           
Only those seeds harvested from fields having prescribed field standards and possessing required seed standards are certified by the Certification Agency. Seeds thus certified are offered for sales. For further details nearer seed certification office may be contacted.

Field and seed standards for pearlmillet certified seed

Field Standards (Certified seed)

 

Factor

Maximum
permitted (%)

Offtypes at any one inspection at and after flowering

0.10

Plants infected by downy mildew disease at any one inspection

0.010

Ergotted earheads at final inspection

0.040

Seed Standards (Certified seed)

 

Factor

Standard

Pure seed (minimum)

98.0%

Inertmatter (maximum)

2.0%

Other crop seeds (maximum)

20/kg

Weed seeds (maximum)

20/kg

Ergot sclerotia, seed entirely or partially modified as sclerotia, broken sclerotia or ergotted seeds (maximum)

0.040% (by number)

Germination (minimum)

75%

Moisture (maximum)

12.0%

For vapour proof containers (maximum)

8.0%

Get more informations regarding seed certification from nearby seed certification office.                                                                                                                                      

QUALITY SEED PRODUCTION IN PEARL MILLET HYBRIDS

Pearlmillet hybrids and their parental lines

Hybrid

Male

Female (male sterile)

KM2

K60-T230

MS 5141 A

X7

PT 1890

L111A

Land selection for seed crop
           
Sandy loam with organic matter and good drainage are well suited for hybrid seed production. The previous crop should not be pearlmillet. If so, irrigate the land once, and let the seeds shed from the previous crop to germinate and then plough to kill the seedlings. This enables to avoid volunteer plants.

Isolation distance for maintaining genetic purity
           
Cross pollination in pearlmillet is 64-85%. To avoid cross pollination with other verities you have to maintain the following isolation distance. 

Contaminants

Isolation distance (minimum)

 

Foundation seed

Certified seed

Fields of other varieties including commercial hybrid of the same variety

1000

200

Fields  of the same hybrid not conforming to varietal purity requirements for certification

1000

200

Fields of the other hybrid having common male parent and conforming to varietal purity requirement for certification

-

5

Fields of other hybrids having common male parent but not conforming to varietal purity requirement for certification

-

200

Season for seed production
           
Crop growth and yield may depend on environmental condition. So, cropping at the appropriate season is very important. During seed maturation stage non rainy, dry and cool climate is essential. For peralmillet hybrid seed production. November – December sowing is the most suitable.

Nursery formation and seed selection

Seed selection
           
To get a good crop, quality seeds are to be used. Quality seeds can bring about self sustainability in food grain production. For proper crop growth, quality seed is the basic need. For getting adequate plant population, use seeds for which germination potential has already been tested. Quality seeds must be separated from stones, sand, debris and other crop seeds. To remove the seeds affected by ergot disease, use salt solution.

Seed rate
           
Female parent seeds of 3.25 kg and male parent seeds of 0.625 kg are needed for one ha.

Nursery formation
           
Nursery area of 300 m2 is enough to get seedlings for one ha. Plough the land 3 to 4 times and during the last ploughing apply 750 kg well decomposed FYM. In each plot of nursery (40 m2) form 6 raised beds with the size of 15 x 3 m with 15 cm height. Keep drainage channels of 30 cm width all around the raised beds.

Sowing
           
In the raised beds, make furrows with 1 cm deep at 15 cm spacing. In these furrows, sow seeds. Sow male and female seeds in separate beds. Cover the seeds with 200 kg FYM. To avoid stem borer damage of seedling, apply 250 g carbofuran granules mixed with 2 kg of moist sand.

Irrigation
           
Maintain the moisture level in the raised beds. On any account the nursery should not go dry.

 Seedling age
           
Eighteen day old seedlings are suitable for transplantation in the main field in order to get good crop standard and high seed yield.

Main field preparation and transplantation
           
In the selected land with good drainage facility apply 12.5 tonnes of FYM per ha, spread uniformly and plough three times.

Ridges and furrows formation
           
Form ridges of 5 m length with 45 cm spacing. Transplant male and female seedlings in 1:6 ratio with one row of male plants alternated by  six rows of female.

Transplantation
           
Apply fertilizer at the bottom of ridge and irrigate sufficiently. Irrigate the nursery before pulling out the seedlings and take care not to damage root tips. Dip the seedlings in the solution prepared by mixing 1000 g Azospirillum in 40 lit. water for 15-30 minutes. A spacing of 15 cm between the plants can be followed. Transplanting is done with 4 border rows of male seedlings around the main field.

Fertilizer application

Fertilizer

N kg/ha

P kg/ha

K kg/ha

Basal
Top dressing
(30 days after sowing)

50
50

50
-

50
-

At tillering stage, apply DAP 1% solution as foliar spray.

Irrigation Management
           
Life irrigation must be given at 3rd day after sowing. After that, irrigate once in 7 to 10 days. During the critical stages like tillering, flowering and seed development stages, enough moisture should be there in the field.

Weed control
           
Weeds are competing with crops for nutrients, sun light and water. It harbours pests and diseases also. So, weed control is compulsory.            
Third day after sowing, spray the herbicide, Atrazine 500 g after mixing it in 1000 lit water using a hand sprayer. One hand weeding between 30-40 days is to be done.

Roguing
           
Rogue and offtype plants causes genetic contamination. Hence, they must be removed from the seed field. If the seed field is offered for certification, Seed certification officer will be inspecting at different stages.


Inspection stage

Factors to be considered during inspection

First – before flowering (30 days)

Isolation distance, volunteer plants, planting ratio, disease infected plants.

Second and Third  - flowering stage

Isolation distance, pollen shedding plants, offtypes, green ear affected plants.

Fourth – Seed maturation stage and before harvest

Ergot and green ear affected plants.

           
Rouging should be carried out both in the male and female rows. Presence of fertile counter part of female plants in the female rows is called pollen shedders. These plants can easily be identified by the hanging anthers which are yellowish, plumpy and pollen filled. In some of the female plants, fertile anthers may be hanging out only from a portion of the panicle. Such plants are called partials, which should also be identified and rogued out.           
Do not leave the removed pollen shedders in the field itself. Take them away from the field. Otherwise pollen grains may disperse from the pulled out plants affecting the genetic purity of the hybrid seeds.

                                                  

                              
Receptive stigma in Pearl millet panicle                          Anthesis in Pearl millet panicle

Harvesting and threshing
           
Crop should be harvested at appropriate time. Harvesting of immature seeds will lead to shriveling of seeds, germination potential of which will be very low. Delayed harvest will lead to germination of seeds in the panicle itself. Seed shedding may also occur causing yield loss. Seeds may be discoloured due to microbial infection. So, harvesting at appropriate stage is essential for high quality. Leaves will turn brown at seed maturity stage. At this stage the seed will have high drymatter content and vigour with high germination potential. Seeds will have 20-25% moisture content. First, harvest the male parent and remove the earheads from the field. Then harvest the female plants which bear the hybrid seeds.

Attention
     
Remember that the seeds harvested from the female parent is the hybrid seed.

Threshing
           
Moisture content of 15-18% is optimum for threshing. If the moisture content is high, it leads to crushing injury which may cause pathogenic infection - Low moisture may cause cracking up of the seeds.

Drying
           
Seeds should be dried under mild sun. Avoid drying between 12 noon and 3 pm. If mechanical driers are employed, the drying temperature should not go beyond 40°C.

Seed processing and grading
           
Immature, broken and pests and disease attacked seeds should be removed to maintain seed quality during storage. Round perforated sieve of 4/64" size is appropriate for processing. Cleaner cum graders may be used for processing.

Seed storage
           
For short term seed storage use fresh and clean cloth bags. But in the high humid areas, use moisture vapour proof containers (700 guage polyethylene bags) for storage.

Seed moisture content
           
Maximum seed moisture content of 12% for the moisture pervious container like cloth bag and 8% for moisture vapour proof container are recommended.

Seed treatment
           
Treating the seeds with fungicides can maintain the germination during storage. Mix 2 g Captan or Thiram with 200 mg Carbaryl in 5 ml of water per kg of seeds.

Seed certification
           
Seed certification guarantees the quality of seed as it ensures that the certified seed has the genetic, physical, physiological and seed health qualities.  Genetic purity means that the seed gives rise to a plant which conforms to the varietal characteristics of the variety. The physical purity means that the seed is free from stones, broken seeds, straw bits and leaf bits etc. Physiological quality is measured by germination and seed health envisages freedom from pest and diseases.
           
Seed certification is being done in many stages. It starts from verifying whether seeds were obtained from authenticated source, verification of isolation distance and inspection during plant growth, flowering, harvesting, processing and bagging. Also seed samples are drawn form the seed lot and sent to seed testing lab to test whether the seeds are possessing required physical purity and germination. Then certification tag is issued. Colour of the tag is blue for certified seeds.
           
Only those seeds harvested from fields having prescribed field standards and possessing required seed standards are certified by the Certification Agency. Seeds thus certified are offered for sales. For further details nearer seed certification office may be contacted. 

Field and seed standard for seed certification

Recommendation

Maximum (%)

 

Foundation seed

Certified seed

Offtype (in female parent) in any of the inspection

0.05

0.10

Offtype (in male parent) in any of the inspection

0.05

0.10

Pollen shedding heads in seed parent at any one inspection at following

0.050

0.10

Green ear (female parent)  in any of the inspection

0.05

0.10

Green ear (male parent) in any of the inspection

0.05

0.10

Ergot disease (female parent) in the last inspection

0.02

0.04

Seed standard

 

Factor

Standard

Physical purity (minimum)

98%

98%

Inert matter (maximum)

2%

2%

Other crop seeds (maximum)

10/kg

10/kg

Weed seeds (maximum)

10/kg

20/kg

Diseased seeds

0.02%

0.04%

Germination (minimum)
Moisture (maximum)

75%

75%

Moisture pervious container

12%

12%

Moisture vapour proof containers

8%

8%

 
© All Rights Reserved. TNAU - 2015.