Quality Seed Production Muhammad Umer 2008 ag2484 Agronomy

Quality Seed Production Muhammad Umer 2008 -ag-2484 Agronomy 7 th

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

Seed Any part of plant which is used for 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. �

Classes of improved seed � Nucleus Seed � Breeder Seed � Certified Seed

Procurement of class 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.

Reporting to Monitoring Agency Following information must provide to Monitoring Agency. � Season � Year � Field � Town � Class of seed

Seed Production in field 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

Selection of appropriate 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.

Sowing a class of improved seed � 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.

Maintenance of recommended isolation distance 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

Isolation distance of different crops Crop Seed Isolation distance (m) Wheat Pure Lines 3 Hybrids 100 Inbreds 400 -600 Hybids 200 -300 Rice Maize

Establishment of appropriate male : female ratio � Male : Female ratio is relevant only in case of hybrid varieties where F 1 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.

� 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

Following recommended agronomy 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.

Objectionable weeds and designated diseases for seed production of some crop species Crop Objectionable weeds Designated diseases Wheat Convolvulus arvensis Loose Smut Jowar Nil Grain smut Head smut Bajra Nil Grain smut Green ear Cow pea Nil Anthracnose Moong Nil Halo Blight

Roughing off types � 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.

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 maintained or not. � Roughing is being done or not.

When to make inspection? In general field inspection may be made during following five stages. � Pre-flowering. � Flowering. � Post-flowering. � Pre harvest/Physiological maturity. � Harvesting.

Seed Processing � 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

Objectives of 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

Seed Drying � 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.

How to Dry Seeds � Natural Drying Seeds are spread uniformly at neat and clean place and dry under natural conditions i. e under sun. � Artificial Drying Different artificial driers are used to dry seeds.

�Bag Driers �Box Driers �Bin Driers �Continuous Flow Tower

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

Seed Grading Removal of under sized/under weight seeds from seed lot. Grading is done on the basis of � Length � Width � Thickness � Density of seed

Seed Treatment 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. �

Temperature Treatment Exposing seeds to such a high temperature which is able to kill the pest/pathogen associated with seed without damaging seed viability. Chemical Treatment • Seed dressing • Fumigation

Seed Packaging � Seeds are packed in bags of appropriate quality and size. Choice of packing material depends 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 Labelling All seed bags must carry printed information about � Crop � Variety � Class of seed � Name and address of producer � Physical purity(%)

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

Major Seed Production units in Pakistan � Syngenta � 4 Brothers Group � Punjab Seed Corporation � Pioneer Pakistan Seed Limited � Ali Akbar etc.

Summary

References � Seed Science and Technology, A. K. Joshi and B. D. Singh. � Principles of Seed Science and Technology 4 th Edition by Lawrence O. Copeland Miller B. Mc. Donald.