Maintenance Breeding

·???? Maintenance Breeding: It deals with principles and method of breeder seed production and maintenance.

·???? This followed to maintain genetic purity of variety or parents of hybrid.

·???? It is varietal maintenance technology.

·???? Maintenance breeding used to maintain genetic and physical purity of released and notified variety.

·???? In maintenance breeding, seed health is necessary.

·???? Breeder and foundation seed used as base material for maintenance breeding program.

·???? It prevents varietal deterioration.

·???? Harrington (1952): Procedure for multiplication of nucleus seed

Multiplication of Nucleus Seed:

1.?? Sampling of variety to obtain nucleus seed

·???? Select 200 plants, inferior discarded

·???? Wrap in cloth bag

2.?? Table examination of samples

3.?? Location and seedling of nucleus seed

4.?? Inspection of nucleus seed plots and removal of off types

5.?? Harvesting and threshing

Maintenance of Breeder Seed of Pre-Released or Newly Released Varieties:

·???? Selection of field

·???? Isolation

·???? Agronomic practices

·???? Breeder seed produced at station in the area where the variety is to be released

·???? Sufficient spacing

·???? Rouging

·???? Harvesting

Maintenance of Breeder seed of established varieties done by:

i)??? By raising crop in isolation

ii)? Bulk selection

Maintenance of Nucleus seed of inbred lines:

·???? Hand pollination

·???? Seedling of hand pollinated seed

·???? Isolation

·???? Inspection of double row plots and rouging

·???? Harvesting, drying and shelling

Maintenance of Breeder seed of inbred lines:

·???? Land requirement

·???? Isolation

·???? Rouging

·???? Field inspection

·???? Harvesting, drying

? It prevents cultivars from genetic deterioration, so prolongs life of variety.

? It deals with purity of improved cultivars and parents of hybrids.

? It enables quality seed production.

Quality Seed Production:

·???? Seed Quality: properties contributing to seed performance

Seed Quality Attributes:

1.?? Physical Attributes:

·???? Minimum damages seeds

·???? Minimum weed seed or inert matter

·???? Uniform seed size

·???? Disease free seeds

2.?? Physiological Attributes:

·???? Germination and Viability

·???? Seed Vigor

3.?? Genetic Attributes:

·???? Seed of same variety

·???? Adopted to local conditions

·???? Pests and disease tolerance

·???? High yielding ability

4.?? Storability:

·???? Moisture content

·???? Temperature of environment

·???? Seed treatment

Factors for Varietal Deterioration (Kadam, 1942)

1.?????? Developmental Variation

2.?????? Mechanical Mixture

3.?????? Mutation

4.?????? Natural Crossing

5.?????? Genetic Drift

6.?????? Minor Genetic Variation

7.?????? Selective Influence of Disease

8.?????? Techniques of Plant Breeder

9.?????? Breakdown of Male Sterility

10.??? Improper Seed Certification System

Maintenance of Genetic Purity during Seed Production:

?? Use of approved seed only in seed multiplication

?? Inspection and approval of fields prior to planting

?? Field inspection at various growth stages

?? Sampling and sealing of cleaned lots

?? Adequate isolation

?? Rouging

?? Periodic Testing

?? Avoiding Genetic Shifts

?? Certification of Seed Crops

?? Adopting Generation System

?? Grow Out Test

Important Safeguards for Maintaining Genetic Purity during Seed Production

1.?? Control of Seed Source

2.?? Preceding Crop Requirements

3.?? Isolation

4.?? Rouging

5.?? Seed Certification

6.?? Grow Out Test

Agronomic Practices

·???? Selection of suitable agro-climatic region

·???? Selection of seed plot

·???? Isolation of seed crops

·???? Preparation of land

·???? Selection of variety

·???? Seed treatment

·???? Time of planting

·???? Seed rate

·???? Methods of sowing

·???? Depth of sowing

·???? Rouging

·???? Pollination

·???? Weed control

·???? Disease / Insect control

·???? Nutrition

·???? Irrigation

·???? Harvesting of seed crops

·???? Methods of harvesting

·???? Drying of seeds

·???? Storage of raw seeds

Seed Production:

·???? Seed Act: 1966

·???? Seed Rules: 1968

·???? Seeds Control Order: 1983

·???? Indian Minimum Seed Certification Standards: 1988 and revised in 2013

Seed Certification:

·???? It is legally sanctioned system to maintain quality of seeds during seed production, post harvest operation and distribution of seeds.

·???? It is a quality assurance process.

·???? It includes field inspection, seed quality tests, pre and post quality check.

·???? Certification is voluntary, but labelling is compulsory.

·???? In India, field evaluation of seed crop and its certification started with establishment of National Seed Corporation (NSC) in 1963.

·???? Maharashtra was the first state to establish official seed certification agencies during 1970 as a part of department of agriculture.

Principles for Forming Seed Certification Agency:

·???? It is not involve in seed production and marketing.

·???? It should have autonomy

·???? Procedure should be uniform throughout the country

·???? It is closely associated with technical institutes.

·???? It should operate on no profit and no loss basis.

·???? It should have adequate technical staff.

·???? It facilitates for timely inspection of seed field.

·???? It serves for the interest of seed producers and buyers

Objectives of Seed Certification:

·???? Maintain and make available to farmers, high quality seeds and propagating materials of notified varieties.

·???? Ensure the acceptable standards of seed viability, vigor, purity and seed health

·???? To ensure genetic identity and genetic purity

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A well organized seed certification help in fulfilling following objectives:

§? Systematic increase of superior varieties

§? Identification of new varieties

§? Provision for continuous supply of comparable material by careful maintenance

Unit of Certification: ?

·???? It is all under one variety.

·???? It does not exceeds 10 ha

·???? It is not divided into field separate by more than 50m between them.

·???? It meant to produce seed belonging to same class and stage in generation chain.

·???? Crop over entire area more or less of same stage of growth

·???? It raised strictly as single crop and never as mixed,

Phases of Certification:

1.?? Receipt and scrutiny of application for seed production

2.?? Verification of seed source and registration of sowing report

3.?? Field inspection

4.?? Seed processing and packing supervision

5.?? Seed sampling and analysis in lab

6.?? Grant of certificate and tag, tagging and sealing

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