Seed :: Fibre :: Cotton(Varieties)

QUALITY SEED PRODUCTION IN COTTON VARIETIES

Land selection
           
Soil texture and fertility of land should be according to the requirements of seed crop. The land should be free from volunteer plants, weed plants and other crop plants. It should be comparatively free from soil borne diseases and insect pests. In the previous season the same crop should not have been raised. If so, irrigate the field well in advance and allow the self sown seeds to decay which left in the pervious season. Select land with good soil fertility and drainage facility.

What are valunter plants?

Volunteers are plants that grow in the field from the seeds in the soil.These seeds should have been fallen from previous season crop. Since they grow without sowing or they volunteer to grow by themselves,hence the name volunter.

Isolation distance
           
Cotton is an often crops pollinated crop and the extent of natural crops – pollination depends upon insect activity. A minimum isolation distance of 50 metres for foundation seed class and 30 metres for certified seed class production, from fields of other varieties of the same species, other species and field of the same variety not conformity to varietal purity requirements for certification, is necessary. By isolating two fields, out crossing between varieties can be prevented so that genetic purity is maintained.

Season
           
It is very important to select optimum season for seed production. Seed quality depends on the prevailing environment, in seed crop, maturity stage should not coincide with rain. Dry cool season is ideal for seed production.

Selection of varieties

Season and varieties
           
The following table indicates the selection of varieties / hybrids according to the area and season.

Season Dated Varieties Hybrids
Winter irrigated (Aug-Sep) Coimbatore, Dindigul, Erode, Madurai, Theni MCU 5, MCU 5VT, MCU9, MCU11, Suvin, Savitha, MCU-13 HB 224, TCHB 213, Jayalakshmi
  Dharmapuri MCU5, MCU 11, Savitha Jayalakshmi
TCHB 213
HB 224
  Salem
Namakkal
MCU 5, MCU 9,
MCU 11, Suvin, Savitha
Jayalakshmi
TCHB 213
HB 224
  Cuddalore Villupuram MCU 5, MCU 9
MCU 11, Savitha
Jayalakshmi
TCHB 213
HB 224
Summer (Feb-March)
Irrigated Erode
MCU 5 VT, MCU5, MCU9, MCU 11, LRA 5166,
SVPR 2
Jayalakshmi
TCHB 213
HB 224
  Madurai, Dindigul,
Theni
MCU 5 VT, MCU5, MCU9, MCU 11, LRA 5166,
SVPR 1, SVPR 2 
Jayalakshmi
TCHB 213
HB 224
  Sivaganga,
Tirunelveli,
Ramnad, Virudhunagar
MCU 5, MCU 9,
SVPR 1, SVPR 2
Jayalakshmi
TCHB 213
Short Duration (Jan-Feb)
Erode, Dindigul, Theni, Madurai, Trichy, Tiruvahur, Tanjore, South Arcot, Ramnad,
Karur, Nagapattinam, Cuddalore, Villupuram
MCU 7  
Medium Duration (Jan-Feb)/
Trichy, Pearmbalur, Karur, Tanjore, Erode, Nagapattinam, Tiruvarur
LRA 5166  
Winter rainfed (Sep.-Oct)
Madurai, Theni
MCU 10, LRA 5166, K 10, K11  
  Dindigul,
Dindigul
Paiyur  
  Ramnad,
Sivaganga,
Virudhunagar
MCU 10, LRA 5166
K11, KC 2, KC3
 
  Tirunelveli,
Thothukudi
K11, K 9, K 10, Paiyur 1,KC 2  
  Dharmapuri MCU 10 LRA 5166, Paiyur  
Rice fallow Tanjore, Thiruvarur, Nagapattinam, Trichy, Karur,Cuddalore, Villupuram ADT 1, MCU 7, SVPR 2  

 Varieties and seed rate  

Seed rate varies with variety, naked seed, fuzzy seed and delinted seeds.

Varieties / Hybrids Seed rate (Kg/ha)
  Fuzzy seed Delinted Naked seed
SVPR 2, MCU 5, MCU 5 VT, MCU 9, MCU 7, MCU 11, MCU 13 15 7.50 -
Suvin - - 6.00
KC 2, KC 3 20.0 15.0 -
Jayalakshmi HP 224 3.75 2.50 -
TCHB 213 1.00. - -

Selection of seeds
           
For getting uniform growth, quality seeds should be used. Always fresh seeds alone should be used. Avoid using old stored seeds because seeds usually stored for more than a year will have low germination potential. For getting quality seed, soak the delinted seeds  in double the volume of water for three hrs. Then dry the seeds under shade to the original moisture content. Then again place the shade dried seeds in water. The dead seeds will float on the water column. Remove all the dead seeds (i.e.) floaters. Seeds settle at the bottom (i.e.) sinkers all of good quality. The heavier the seed, the greater will be the germination and vigour potential. The good plumpy seeds ascribed to the relatively large embryo associated with large amount of food reserves and their efficient mobilization enabling the production of seedlings to large size.

Note: Dead seed separation is possible only in delinted seeds.

Seed treatment

Acid delinting
           
For delinting one kg of fuzzy seed 100 ml of conc. sulphuric acid is required. Taken empty plastic bucket or enamel bucket and pour the acid uniformly over the  seeds. Then stir vigorously and constantly with a wooden stick for two to three minutes till the fuzz sticking to the seeds is completely digested and the seed coat attains a dark brown colour of coffee powder. Then wash the seeds with water for 5-6 times to remove all the traces of the acid. All the ill-filled, damaged insect attacked, diseased, broken, very small and immature seeds that are floating are to be removed. The good, well filled and healthy seeds that remain at the bottom of the bucket alone should be taken. First shade dry the seeds then sun dry the seeds.

Note

  • Do the acid delinting with at most care
  • Use only plastic buckets
  • Do not use materials made up of metal
  • Do not stir beyond 2-3 minutes. Otherwise there are chances of seed injury and death of seeds.

Advantages of Acid delinting

  • External seed borne disease causing organisms are eliminated
  • Eggs, larva and pupal of bollworms present on the seed coat destroyed.
  • Helps to separate immature, broken il-filled, cut and damaged and shriveled seeds.
  • Makes seed treatment more effective and easy
  • Facilitates easy sowing and handling 
  • Improves germination and uniformity in germination.

Seed treatment
           
Treat acid delinted seeds with bavistin or thiram or captan @ 2 g/kg of seeds. Sow the seeds after 24 hrs of treatment.

Field preparation
           
Plough the field 3 or 4 times to fine tilth. Spread 12.5 tons of FYM or compost per ha uniformity before the last plough and level the field perfectly. Improper leveling creates problem in irrigation which leads to differential flowering and there by the seed yield is reduced to a greater extent. Then select the varieties suitable for the season. Sow the seed at 3 cm depth. Adopt the spacing as mentioned below.

Varieties / hybrids Spacing (cm) Between rows Between plants
MCU 5, MCU 5 VT, MCU 9, MCU 11,MCU 13 SVPR 2,LRA 5166 75 30
KC 2, KC 3 45 15
Jayalakshmi TCHB 213
HB 224
120 60
Suvin 90 45
MCU 7, ADT 1 and
SVPR 1
60 30

The fertilizer recommended varies with varieties.

Varieties / Hybrids Quantity of fertilizer (kg/ha)
  N P205 K2O
MCU 7 60 30 30
MCU 5, MCU 5 VT, MCU 9 80 40 40
MCU 11, MCU 13 and Suvin 80 40 40
Jayalakshm, TCHB 213 HB 224 120 60 60

Varieties and fertilizer application
           
Fertilizer should be applied in split dose according to the varieties.

Varieties / Hybrids Quantity of fertilizers (kg/ha)

 

Basal (18-20 days of sowing) I top
(40-45 DAS)
II top
(60-65 DAS)

 

N P K N P K N P K
MCU 7, MCU 5, MCU 5 VT 30 30 30 30 - - - - -
MCU 9, Suvin, MCU 11, MCU 13 40 40 40 40 - - - - -
Jayalakshmi HB 224 TCHB 213 40 60 60 60 - - 40 - -

Varieties and split up application of fertilizers
           
If basal application could not be done, apply fertilizer on 25th day after sowing.

Weed management
           
Maintenance of weed free condition is important. Apply any one of the following pre emergence herbicides three days after sowing. Fluchloralin (2.2lit/ha) or pendimethalin (3.3 lit/ha) application followed by hand needing at 35-40 days after herbicide application. If herbicide is not applied do the first hand weeding within 15-20 days.

cotton 1

Intercultural operation by using iron plough

Gap filling
           
Seedling can also be used for gap filling instead of seeds. For gap filling sow seeds in 150 gauge thick polythene bags of size 15 cm x10 cm filled with FYM and soil in the ratio of 1:3, make holes at the bottom of the bag to drain excess water.  Dibble the seeds in poly bags on the same day when the sowing is taken up in the field place these bags under shade and irrigate daily. Gap filling should be done within 10 days of sowing.  Plant seedlings maintained in the poly bags one in each of the gaps in the filed by cutting open the poly bag and plant the seedling along with the soil intact and then irrigate.

cotton 2

Gap filled field

Thinning
           
Thin out the seedling and allow only one healthy seedling per hill. Thinning should be done within 15 days after sowing.

cotton 3

Cotton field after Thinning

Importance of roguing
           
Adequate and timely roguing is extremely important in seed production. They should be removed at the earliest possible date before flowering. It is wise to remove the whole plant and not just the flower by hand. Some times there may be differences in crop growth, variation in height, flowering duration and maturation etc., some plants flower very early and some pants flower very late. If the variety used is genetically pure there won’t be any variation in the filed.  If variations are observe it is mainly due to genetic contamination (or) admixture of varieties. Because of these variations seeds after harvest can not be used for further sowing and such field will be rejected for seed production.           

Weed plants will compete with seed crop for space, nutrients etc., seeds of weeds get mixed with crop seed easily. In order to avoid all these defects plants which are deviating from the concerned variety / hybrid on morphological characters should be rouged out. Remove all the diseases pest infested plants form seed production plot.

cotton 4 

Rouge very tall plant

Stages of crop growth and characters looked into for rouging

Stages of crop growth Characters looked into
Vegetative Height, colour of vegetation, leaf size, colour, shape and orientation, stem colour and diseased plants.
Flowering Leaf flowering, corolla colour, pollen colour, flower stalks, petal spot, bracts shade and pigmentation
Harvesting Based on boll size, shape, colour, beak, texture and pittings.

Foliar application of nutrients
           
Basal application of fertilizers is alone not sufficient. To get well-filled, vigorous seeds, crop needs nutrients at different stages especially through foliage. Spraying of 1% DAP at 70, 80 and 90 DAS, gives good well filled quality seeds with more seed recovery.

DAP preparation
           
Soak 5 kg of DAP in 25 lit of water over night, next day decent the supernatant solution and hold 475 lit of water and spray in the early morning.

 Earthing up
           
Reform the ridges and furrows after first top dressing in such away that the plants are on the tops of the ridges and well support by soil.

Methods to prevent shedding of flower and bolls
           
Shedding of flowers and young bolls squares is a major problem in cotton. To prevent this 40 ppm NAA (Napthalene Acetic Acid) should be sprayed two times; first spray can be taken up at flowering and second spray after a month of first spray.

Preparation of NAA
           
Dissolve 40 mg of NAA in one lit of water.

Breeding

 

Boll setting

Topping / arresting the terminal growth
            Topping is an important technique to be followed, In some of the varieties when they grow very tall the reproductive ability is reduced and thereby boll formation is much affected. In these varieties pinching of the terminal bud will increase axillary buds / side shoots there by increasing the flowers and bolls. Pinching of terminal bud arrests the vertical growth of the plant.

Varieties and arresting of terminal growth 

Varieties Days after sowing No
MCU 5, MCU 9, MCU 11 70-80 15
Suvin, Jayalakshmi , TCHB 90 20

Water Management
           
Irrigation depends on the land. Frequent irrigation is essential in sandy type soil. Irrigation three days after sowing is essential. The crops require copious irrigation nearing maturation. Irrigation should be avoided nearing harvest the water holding capacity should be maintained between 40-50% which enabled good root growth. The crop should not experience drought during the essential growth stages which reflects badly on yield.

Crop growth stages and irrigation

Crop growth stages Days after sowing
After sowing 0
Life irrigation 3
Upto flowering (Regulate) 20-21
Flowering stage (Copious) 35-36
48
60
70
84
96
Maturation stage 108
120
130
140

Note : Irrigation should be stopped beyond 150 days after sowing.

Harvesting
           
Harvesting of bolls should be done at appropriate stage; early harvest results in the production of more of shriveled and low viable seeds. Late harvest results in rancidity of seed oil and lost its viability very quickly. Once in week the bursted bolls are harvested 4 or 5 times. Harvest only in the morning hours upto 10 to 11 a.m. When there is moisture so that dry leaves and bracts do not stick to the kapas and lower the market value. Remove only the kapas from the bolls and leave the bracts on the plants itself.

cotton 5

 

Harvestable maturity
           
Spread a thin layer of dry sand on the ground and keep the kapas over it. The dry sand will absorb moisture and prevent it from come in contact with the kapas is moisture will stain the kapas and lower it value. The first five pickings in winter and four in summer are alone used for seed extraction. Immediately after picking shade dry the kapas for 2-3 days. Do not dry under hot sun which will affect the fiber strength and luster will be lost and lower the market value.

Methods to preserve seed quality

Kapas sorting
           
Stanied, discoloured hard locks, unopened, pest and disease infested, pink boll warm infested kapas should be removed because they will spoil the good kapas and also lower the market value of the produce. Dry the cleaned kapas in a well ventilated place. Dry the kapas on a raised dry sand bed of 1" height.

Ginning
           
Ginning has a big role in cotton seed quality. Ginning of cotton seed should be done on one variety is approved ginning factory by the certification agency. The ginning machinery must be thoroughly cleaned before ginning the seed crop. In ginning the cotton should be subjected to a maximum amount to minimise the mechanical damage.

cotton 6

Seed damage during ginning         
  
Determine the moisture content of each lot of seed cotton to be ginned by using moisture meter. Gin only that cotton with moisture content of 6 to 8.5% at the feeder apron.   Limit cleaning equipment do not more than 21 cylinders to the lowest possible amount to allow for proper ginning. If possible use no more than one saw-type lint cleaner. But never more than two. The rate of ginning should not exceed 4.5 to 5.5 kg of lint cotton per saw per hour. On conventional it stands with 30 cm saw maintain rib spacing at 1/8' t the point where the saw enters between the ribs maintain loose seed roll at all times.

 Seed drying
           
After ginning seeds should be dried immediately. While drying under sun the seeds should be dried between 8 am to 12 noon and 3 pm to 5 pm only. The time between 12 noon to 3 pm should be avoided because during this time the uv radiation will be more which will affect the quality of the seeds. Continuous drying should be avoided. A gap should be given between two continuous drying.      

Seed processing
           
During seed processing the immatured ill-filled broken spoiled seeds other crop seeds, inert mater are removed. The seed separation based on density using specific gravity separator result in good quality seeds.
           
Proper cleaning should be done before operation of any equipment each time before the processing of each variety otherwise physical admixture will occur.

Seed storage
           
Seed storage is another important area next to seed production. Seed storage is the period of preserving the quality of seeds in terms of germination and vigour until the next planting season.

Seed moisture
           
The initial moisture content of the seed is very important which decides the longevity of seeds. Seeds stored with high moisture content will loose viability very shortly under storage. Seeds dried to 10% M.C. and packed in gunny bag or cloth bag can be stored for a shot period. For long term storage seeds should be dried to 6% moisture content and packed in moisture vapour containers.  

Seed treatment
           
Before storing, seed can be treated with any fungicide. Seeds can be treated either with captan or thiram @ 2 g/kg of seeds. Halogenation is another seed treatment method. Calcium oxy chloride and calcium carbonate are mixed at equal proportion and placed in a container for a week. The mixture can be used @ 4 g kg of seeds. This is cost effective, safe and ecofriendly method of seed treatment.

Containers
           
Seeds are hygroscopic in nature. Hence based on the existing environmental conditions seeds can absorb or let the moisture. In humid and coastal area it is better to use moisture vapour proof containers (700 gauge polythene bags). Always use fresh bags.
           
Care should be taken while staking. The seed bags can be stacked to a maximum of 6 or 7 bags only otherwise seeds in lower bags get affected due to over pressure. Stake the bags over wooden pallets / Tarpaulin.  Bags should not come in contact with side walls or floor.

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.

Minimum seed certification standards of certified seeds

Factors Maximum permitted %
Rogues 0.02%
Seed Standards
Pure seed (mint) 98.0%
Inert metter (max) 2.0%
Other crop seeds (max) 10% kg
Weed seeds (max) 10% kg
Germination (min) 65.0%
Moisture (max) -
Moisture pervious container 10%
Vapour proof container 6.0%
Updated On: April 2016
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