Quality Seed Production

Muhammad Umer 2008-ag-2484

Agronomy 7th

Procurement of class of improved seed. Reporting to Monitoring Agency. Seed Production in field. Seed Processing. Seed Marketing.

Contents

Any part of plant which is usedfor further propagation is called seed. A seed is a miniature plant supplemented

with reserved food and protected by an outer covering.

Ripened ovule(female part of flower) is also called seed.

Seed

Nucleus Seed Breeder Seed Certified Seed

Classes of improved seed

Seed Producing agency or individual must have access to a class of seed,one step higher than class of seed that is intended to be produced.

For example for producing breeder seed,the producer must have access to nucleus seed.

Planning for seed production should start few years before production,at least four years for strong seed chain production.

Procurement of class of improved seed

Following information must provide to Monitoring Agency.

Season Year Field Town Class of seed

Reporting to Monitoring Agency

It includes: Selection of appropriate field Sowing a class of improved seed Maintenance of recommended isolation distance Establishment of appropriate male : female ratio Following recommended agronomy Roughing off types Field inspection Harvesting,threshing and storage with care

Seed Production in field

Soil should have good drainage,fertility status and not deficient in micro and macro nutrients.

Field should be free from weed seeds. Passport traits should express.

Selection of appropriate field

For seed production row to row spacing is kept more so that there is enough space for movement in field for roughing,inspection etc.

For breeder seed every after two row one row is left fallow so that proper seed formation takes place.

Sowing a class of improved seed

Protect seed production plots from other fields of same crop so that no risk of contamination by pollen from neigbouring fields occur.

Spatial isolation Temporal isolation Mechanical Isolation

Maintenance of recommended isolation distance

Crop Seed Isolation distance (m)

Wheat Pure Lines 3Hybrids 100

Rice Pure Lines 3Hybrids 100

Maize Inbreds 400-600Hybids 200-300

Isolation distance of different crops

Male : Female ratio is relevant only in case of hybrid varieties where F1 is result of cross pollination between two parents.

Female parent bears the hybrid seed. Male : Female ratio is generally kept in

favour of female parent in order to minimize seed cost.

Establishment of appropriate male : female ratio

The male and female ratio is decided on basis of experimental investigations.

Crop Male : female ratio

Maize 1:2 , 2:4

Rice 1:4 , 2:10

Cotton 1:2

Agronomic practices starts from sowing of crop till harvesting,which involves fertilizer application,irrigation,weed and pest management.

Presence of Obnoxious weeds and diseases reduce physical purity of seed.

Integrated weed control measures,use of resistant varieties and seed treatment.

Following recommended agronomy

Crop Objectionable weeds

Designated diseases

Wheat Convolvulus arvensis Loose SmutJowar Nil Grain smut

Head smutBajra Nil Grain smut

Green earCow pea Nil AnthracnoseMoong Nil Halo Blight

Objectionable weeds and designated diseases for seed production of some crop species

Roughing is the removal of off-type(those plants that are phenotypically different from plants of the variety grown as seed crop) plants from a field.

Roughing should start before flowering and continue till maturity.

Roughing should be done several times under supervision of technical experts.

Roughing off types

Field inspection refers to the scrutiny of seed production plots by a team of qualified persons. It is checked that source of seed is approved or not. Male : Female ratio is maintainedor not. Roughing is being done or not.

Field inspection

In general field inspection may be made during following five stages.

Pre-flowering. Flowering. Post-flowering. Pre harvest/Physiological maturity. Harvesting.

When to make inspection?

Seed processing means improving the quality of harvested seed including several operations starting from harvesting of seed crop till its marketing through

Drying Cleaning Grading Packaging Labelling

Seed Processing

To improve seed quality through removal of adulterants,non seed material,broken seeds.

To maintain seed viability and vigour. To Make seed handling easy. To increase real value of seed. Real value=Purity (%)×Germination (%) 100

Objectives of Seed Processing

Reduction in seed moisture content to a safer limit is called seed drying.

Its objective is to maintain seed viability and seed vigour for longer period of time during storage.

If moisture contents are high,higher chances of insect pests attack and deteriorate quality of seed due to higher respiratory activities.

Seed Drying

Natural DryingSeeds are spread uniformly at neatand clean place and dry under natural conditions i.e under sun. Artificial DryingDifferent artificial driers are used todry seeds.

How to Dry Seeds

Bag Driers Box Driers Bin Driers Continuous Flow Tower

Seperation of physical impurities or removal of non seed material from seed.

Seed Cleaning

Removal of under sized/under weight seeds from seed lot.Grading is done on the basis of

Length Width Thickness Density of seed

Seed Grading

Seed treatment refers to exposure of seed to certain chemical or physical agents which are able to protect them from pests and provide good health to the seed.

Infected seeds may fail to germinate. Infected seeds lead to Introduction of

pathogens into new areas.

Seed Treatment

Temperature Treatment Exposing seeds to such a high temperature

which is able to kill the the pest/pathogen associated with seed without damaging seed viability.

Chemical Treatment • Seed dressing• Fumigation

Seeds are packed in bags of appropriatequality and size.Choice of packing materialdepends upon type of crop,amount of seed

and storage conditions.Packaging materials are of three types. Moisture-vapour resistance,e.g polythene. Moisture-vapour permeable,e.g cloth,paper

bags Moisture-vapour proof,e.g Tin cans.

Seed Packaging

All seed bags must carry printed information about

Crop Variety Class of seed Name and address of producer Physical purity(%)

Seed Labelling

Genetic purity(%) Moisture(%) Germination(%) Date of germination Date of test Net Content

Syngenta 4 Brothers Group Punjab Seed Corporation Pioneer Pakistan Seed Limited Ali Akbar etc.

Major Seed Production units in Pakistan

Summary

Seed Science and Technology, A.K.Joshi and B.D.Singh.

Principles of Seed Science and Technology4th Edition by Lawrence O.Copeland and Miller

B.McDonald.

References