Porella : features, morphology, anatomy, reproduction etc.
Principles of hybrid seed production
1. PRINCIPLES OF HYBRID SEED PRODUCTION
Vijaykumar Shrivastav ( M.Sc.Ag - Agronomy)
G. B. Pant University of Ag & Tech, Pantnagar
Seed Professional – MNC (Seeds & Pesticides)
Mobile & WhatsApp - +919925318391
2. Seed Production : Production of genetically pure and otherwise good quality pedigree
seed is an exacting task requiring high technical skills and comparatively heavy financial
investment. During seed production strict attention must be given to the maintenance of
genetic purity and other qualities of seed . Seed production must be carried out under
standardized and well-organized conditions.
Importance of Seed Production :
- Multiplication of superior varieties
- Availability of superior varieties to masses
- Maintenance of genetic purity
- Supply of high quality seeds
- Seeds have high germination status
- Seeds having high vigour and viability status
- Maintaining excellent health status of seed
- Securing high crop yields and income level to farmers
3. Important Safeguards for Maintenance of Genetic purity
- Control of Seed Source / Use of approved seed only in seed multiplications
- Inspection and approval of fields prior to planting
- Providing adequate isolation to prevent contamination
- Seed multiplication outside their normal cultivation area
- Roguing of seed fields at critical stages
- Periodic testing of varieties for genetic purity
- Certification of seed crops to maintain genetic purity and quality of seed
- Frequent field visits and monitoring during all operations
- Grow Out tests
4. Terminology Used in Hybrid Seed Production
Seed :“ Seed is a plant part having living embryo that have a capacity to produce identical plant
and used for raising seed crop or commercial crop.”
A seed, stands for any of the material used for sowing or planting like seed, seedling,
tubers, bulbs, rhizomes, roots, cuttings, grafts and any other propagating materials for food
crops, cattle fodder or floriculture.
Hybrid Seed : The seed ( the F1 generation ) produced from a cross between
genetically dissimilar parents and the hybrid vigour or heterosis is the absolute phenomenon where expression
of the characteristics such as growth related traits, flowering and yield fall outside the range of it’s parents
with superiority.
Germination : Ability of a seed when planted under normal sowing
conditions to give rise to a normal seedling and developing into new plants.
Sowing : Sowing is the process of placing or planting seeds to the soil so they may
grow. In sowing, generally little soil is placed over the seeds and Sowing can be Hand
sowing or by machines.
5. Isolation :The state of being in a place or situation that is separate from others , the condition of being isolated
- Distance Isolation : to be maintained recommended isolation distance as per crop standards
- Time Isolation: to be followed to escape flowering simultaneously within seed and other plot
- Barrier Isolation : Topographical surface features, natural obstacles (Tall crops ), artificial obstacles
Seed Rate : The number or quantity of seeds planted per unit of area (Acre or Hectare) to ensure optimum
population for maximum yield.
Spacing : Refers planting or sowing of seeds maintaining desired distance between row to row and seed to
seed.
Staggering : Refers differential sowing of Male and Female parents
(difference between sowing dates) to achieve proper synchronization
of flowering of both parents during hybrid seed production. Staggering
depends on flowering behavior of both Male & Female parents.
Roguing : Refers to the act of identifying and removing plants with undesirable characteristics from
agricultural or seed production fields. Rogues are removed from the fields to preserve the quality of the crop
being grown.
6. Planting / Row Ratio: It refers to the sowing arrangement of Row
ratio of Female and male lines. Example 4:1 ( 4 lines female : 1 line male).
This is followed in Hybrid Seed Production where 2 parents
(Male & Female ) are used. This is depending on :
- Growth & vigour of pollinator
- Plant height of pollinator
- Size of male panicle and amount of residual pollen
- Stigma exertion of CMS female line
- Duration & angle of floret opening of CMS female line
- Prevailing wind direction & velocity during anthesis time
Synchronization : Simultaneous flowering of male and female parents in
Hybrid seed production is known as synchronization. Synchronization in
flowering between the parental lines assumes greater importance as the
seed set on female parent depends on the amount of pollen supplied from
the male parent during flowering period.
Flowering : Refers to the full blooming of the reproductive
parts of the plants where pollen moves from male organ to
female stigma for pollination.
7. Anthesis : The period during which a flower is fully open and flower becomes sexually functional. Anthesis refers to a
series of events between the opening and closing of spikelet . Anthesis will occur when a portion of the panicle is exerted
and it starts with the spikelet at the tip of the florets.
Emasculation : Removal of male organs ,stamens or anthers or killing the
pollen of a flower without damaging the female reproductive organ is known as
emasculation. In bisexual flowers, emasculation is essential to prevent of
self-pollination. In some crops Hybrid seed production like Cotton, Okra,
Chilli, Tomato etc. emasculation procedure is followed to make female sterile.
Pollination : The movement of pollen from the anthers to the
stigma by wind, female stigma is essential for seed set and therefore crucial in
seed production. In case of Hybrid seed production pollen transfer from male plant
to female plant stigma. The movement took place through wind blowing.
Manual crossing : In case of Hybrid seed production pollen transfer from
male plant anthers to female stigma manually. It is followed in Hybrid seed production
of the crops where emasculation is done crops like Cotton, Okra, Chilli, Tomato etc.
8. Supplementary pollination : Supplementary pollination serves to enhance the outcrossing rate in order to
increase seed set. Supplementary pollination should be done by shaking the pollen parent with the help of
ropes or sticks so that the pollen is shed effectively on A line plants. This is generally followed in Rice Hybrid
seed production.
Harvesting – Harvesting is the process of cutting and collecting the mature crop from the field.
Picking: Refers to the manual collection of ripen plant produce.
Post-Harvest operations : post-harvest handling is the stage of
crop production immediately following harvest, including drying, cleaning, sorting and packing.
Grow-Out Test : Conducted to determine genetic purity of a seed lot wherever it is prerequisite for grant of
the certificate and also on the seed lots where a doubt has been arisen about the genetic purity. The grow-out
tests can be complemented by certain related laboratory tests.
9. Field Selection : The fertile, well levelled with good irrigation and drainage system field should be selected
where same crop was not grown in previous season to make free from volunteer plants to avoid admixture and
any quality issues relates to genetic as well as physical purity.
Field preparation : The field should be fertile and well prepared for good germination and good crop growth.
Seed : The Foundation seed should have quality as per seed standards and it should be from truthful sources. In
case of Open Pollinated (OP) varieties seed production we have to use single parent.
While If we are going for Hybrid seed production (HSP), we have to use 2 parents, Female “A” CMS
Line & Male restorer “R” Line.
In Hybrid seed production of some crops like Maize (Corn) , Pearl Millet (Bajra), Sorhum (Jowar), Rice, Mustard,
Sunflower, Castor, Sorghum Sudan Grass (SSG) etc. female parent (“A” Line) is sterile parent. While is some crops
like Cotton, Okra, Chilli, Tomato etc. we are following emasculation procedure to make female sterile. Below
points are important in Hybrid Seed Production :
A. CMS “A” Line (Female ) desirable characteristics
B. Restorer R Line (Male) desirable characteristics
C. Hybrid F1 desirable characteristics
HYBRID SEED PRODUCTION
10. Desirable characteristics of A Line (Female ):
- Stable and complete male sterility
- Good outcrossing ability
- Good combining ability
- Desirable agronomic characters
Restorer Male R Line : Restorers play an important role both in increasing heterosis as well as in
increasing hybrid seed yield in seed production plots.
Desirable characteristics of R Line (Male) :
- Strong and stable restoration over seasons and locations
- Highly vigorous plant growth habit with large number of spikelet
- Complete dehiscence of anthers and high amount of residual pollen
- Profuse tillering , synchronous heading and concentrated blooming of spikelet
- Multiple disease and pest resistance
- Good outcrossing and combining ability
- Acceptable grain quality
11. Pre-requisites for a Good Hybrid
- Stable cytoplasmic Genetic Male Sterility System
- Adaptability across environments
- Perfect synchronization in flowering
- Height of the male and female parents
- Stigma receptivity and pollen dispersal
- Ease in seed production
- High and economical seed yields
- High level of yields on commercial scale crop
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Hybrid Seed Production - Stages
A x R
(Female parent) (Male parent )
Sterile Fertile
= For Commercial crop growing
F1 Seeds
Out-crossing
Sowing
Vegetative
Boot Leaf
Flowering
Cross Pollination
Seed development
CROP STAGES
Maturity - Harvest
F1 Seeds
Hybrid seed
R
A
F1 Seed
(Hybrid)
A:R Sowing row ratio – 18:2
(It may vary depends on parents flowering behavioral characteristics)
13. Strict Isolation : There are isolation standards varying from crop to crop and for best genetic purity it should
be complied strictly.
Sowing method & spacing : Standard sowing methods are followed as per crop recommendations.
Depending on parents ideotypes we have to arrange row and plant spacing to maintain optimum plant
populations for high yield.
Staggering : Proper staggering should be adopted based of flowering behavior of parents in producing
environmental conditions for perfect synchronization.
Planting Ratio : Correct sowing arrangement ratio of Female and male lines should be followed for optimum
plant population of both parents based on outcrossing ability of female and pollen supply capacity of male.
Female population is important for seed yield and male population for sufficient pollen supply and outcrossing.
In different crops different planting ratio followed depending on parents .
Field monitoring : Scheduled field monitoring is very important for supervision of crop from sowing to
harvesting to ensure timely operations for best quality seed and good seed yield.
Agronomic management : It refers proper management of crop supplying fertilizer, nutrition, and
irrigation timely . Good agronomic management results to good yield and quality.
14. Plant Protection : Refers disease and insect pest management timely to prevent damage to the crop.
Appropriate steps to be taken timely for good yield and quality maintenance.
Rouging : It should be done timely to rogue out undesired plants as off types, pollen shedders in “A” line,
semi sterile plants, volunteer plants, other crop plants and diseased heads etc. For effective roguing of offtypes
it is necessary to have knowledge on the distinguishing characters for identification of A & R lines.
Rouging stages : It should be done timely and prior to any contamination. It is done from vegetative stage
to harvesting based on many parameters as morphological and reproductive characters. The critical stage are
most important as below :
- Vegetative stage - Pre-flowering stage
- Flowering stage - Maturity stage
Synchronization : Crop should be in frequent observations to check nicking / synchronization status for
same time flowering. There may be little variations in flowering based on climatic conditions and flowering
behavior, so in such cases corrective measures should be taken. Male line 2 days advancement is
recommended.
Flowering : It refers to the full blooming of male and female floral sexual parts and pollination takes place.
15. Emasculation : This practice followed in Cotton, Okra (Ladies finger), Tomato, Chilli and other crops where
female line is not sterile. If female is sterile no need of emasculation.
Pollination : It refers male pollen transfer from plants to female stigma .Good pollination is very important
for good yielding. Wind velocity and wind direction plays important role in pollination and rainy weather
conditions will reduce pollination effectiveness.
Manual Crossing / manual Pollination : It is done in crops where emasculation process is done.
Supplementary pollination : For effective pollen dispersal during peak flowering stage for specific period
( days & timing) for maximizing outcrossing for proper seed setting. Generally this practice followed in hybrid
rice seed production.
Seed Development : After crossing / pollination there will be seed formation and development.
Seed Maturity : Refers to the physiological and functional changes that occur from time of anthesis until the
seeds are ready for harvest.
Physiological maturity :Is defined as the occurrence of maximum seed dry weight and represents the end
of dry weight accumulation and seed filling period.
16. Harvesting : 1st Male should be harvested and after male row inspection female rows should be harvested.
Necessary care needs to avoid any admixture.
Picking : Followed in cotton to pick seed lint from bursted bolls and vegetable crops for separating fruits.
Post-Harvest Operations : After harvest drying to be done to achieve optimum moisture %, proper
threshing to be done to avoid seed damage and bagging with proper labelling.
Threshing : Separation of seeds or grains from spike or cob after seed maturity .
Ginning : Mechanical separation of fuzz seed from seed lint is called ginning. This process is followed in
cotton crop produce.
Delinting : Is the process of removal of fuzz from cotton seed . This is the chemical process where acids and
gases are used.
Plant processing : Refers to the mechanical cleaning to obtain maximum percentage of pure seed with
maximum germination potential.
Storage : Seed should be stored in favorable conditions maintaining identity, maintaining purity, protection
from insect pests, maintaining germination with regularly check.
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Seed Production – Key Issues
Field related
Wrong field selection
Isolation
Poor crop management
Wrong nicking
Disease and insect problems
Quality related
Off-types
Pollen shedders
Volunteers
Mechanical mixtures – during
threshing/harvesting
Harvest moisture
People related
Unskilled seed producer’s
Production Cost
Procurement price
Weather related
Drought / Excess and untimely rains
Seed discoloration
Rain damage
Germination issues
Disease and insect problem
Operations related
Sowing time
Rouging time
Harvesting stage
Post harvest operations
Mechanical cleaning – threshing / harvesting
Drying / bagging
Gunny bags lot marking
Dispatch
18. Key deliverables of efficient seed production technology
Highest order of seed quality in terms of genetic purity, seed vigour and germination
Maximization of seed yield per unit area
Reduction of production cost per kg of seed
Freedom from inert matter, weed seed and other crops seed as per prescribed standards
Freedom from seed-borne diseases
Timely availability of seed to customers
19. RESTRICTED
THANK YOU !
SEE YOU AGAIN SHORTLY !
Vijay Kumar
Youtube Channel Name: “JOURNEY WITH VIJAYKUMAR SHRIVASTAV”
published contents :
1. Seed Science and Technology – Basics
Link : https://youtu.be/JxCJnmq3o8s
2. Seed Development Programs & Seed and Agricultural Organizations
Link :
3. Principles of Hybrid seed Production
Link : https://youtu.be/6TvYhv4XG8c
https://youtu.be/kWBc2Eobdxc
