UPMSP Vocational Seed Production Technology cheat sheet

Seed is a fertilised ovule: embryo + endosperm (or cotyledons) + seed coat; germination requires viable embryo, adequate moisture, oxygen and suitable temperature, with light or dark requirement varying by species.

Germination phases: imbibition (physical water uptake, reversible), lag phase of metabolic activation (enzyme synthesis, respiration rise), then radicle emergence and mobilisation of reserves - only radicle protrusion counts as germination.

Dormancy types: physiological (ABA/GA balance, needs after-ripening or stratification), physical (hard seed coat, needs scarification), morphophysiological (undeveloped embryo); combinational dormancy needs both treatments.

Seed vigour = potential for rapid, uniform emergence under a wide range of field conditions; tested by accelerated ageing, electrical conductivity, cold test and seedling growth rate - distinct from viability (percentage that germinate).

Genetic purity is the defining principle of seed production: seed must be true to type, so production fields must be isolated, rogued and derived from an approved source seed class.

Seed classes in a multiplication chain: breeder/nucleus seed → foundation seed → certified seed (and in some systems registered seed); each generation adds a multiplication step and a permitted downgrade in purity.

Self-pollinated crops (wheat, rice, pea) need small isolation distances; cross-pollinated crops (maize, pearl millet, brassicas) need large distances or physical/time barriers because outcrossing rate drives genetic contamination.

Seed weight and quality are fixed at harvest; seed lot quality can only be preserved, never improved, by processing and storage - hence field and harvest decisions set the quality ceiling.

1000-grain weight, test weight and germination percentage are used to compute seed rate: seed rate (kg/ha) = (plant population × 1000-grain weight) ÷ (germination % × purity % × field establishment %).

Nucleus/breeder seed is produced by the originating breeder or institution under maximum supervision; it is the genetic source for all subsequent classes and is renewed only from the breeder's parental lines.

Foundation seed is produced from breeder seed by a designated agency (in India, e.g. State Seed Corporations or NSC) under technical supervision; it is the parent material for certified seed.

Certified seed is produced from foundation seed by registered growers and must meet prescribed field and seed standards; it is the class sold to farmers.

Varietal maintenance breeding keeps a variety genetically pure: controlled selfing or sib-mating, removal of off-types, and periodic renewal of breeder seed from the original nucleus stock.

Generation limits exist for each class (e.g. breeder → foundation → certified) to cap the accumulation of genetic drift; exceeding the limit requires reversion to a higher class.

Growers must keep source-seed certification tags and sowing records; lot identity links every bag of certified seed back to the foundation seed field that produced it.

In hybrid seed production, parental lines (A, B and R lines in cytoplasmic male sterility systems) are maintained separately: A line crossed with B line maintains the A line; A × R produces commercial hybrid seed.

Maintenance of A-line purity requires periodic backcrossing to the B line and rogueing of fertile (B-like) plants in the A-line seed field; the B line is maintained by selfing.

Field history rule: land must be free of the same crop and volunteer plants for at least the previous season (often 2–3 years for cross-pollinated crops) to prevent contamination from self-sown seed and volunteers.

Isolation distance is the minimum separation from any other variety of the same crop in flower; it varies by crop and class - e.g. self-pollinated cereals often 3 m for certified seed, cross-pollinated crops can require 200–1000 m or more.

Isolation can be spatial (distance), physical (barrier rows, tall border crops, net houses) or temporal (staggered sowing so flowering times do not overlap); the choice depends on pollinator type and wind direction.

Roguing = removal of off-types, diseased plants and weeds of the same species before flowering; it must be done at least twice - at vegetative stage and at flowering - and rogued plants must be destroyed, not left in the field.

Off-type indicators: plant height, leaf shape, pigmentation, flowering date, ear/panicle shape, glume or pod colour, seed colour and maturity - record the number of off-types removed for inspection.

Field inspection counts: inspectors sample at random along diagonals; the number of off-types is expressed as a percentage of plants examined and compared with the prescribed field standard for that class.

Weed control must target noxious weeds and same-species weeds (e.g. wild rice in rice, wild oat in wheat) because their seed is hard to separate at processing and can ruin certification.

Disease-free field selection: avoid fields with a history of seed-borne diseases (e.g. loose smut, bacterial blight); isolation also protects against pollen-borne and insect-vectored virus spread.

Wheat and barley: self-pollinated; isolation 3 m (certified) is common; rogue off-types and loose smut-infected ears; harvest at physiological maturity to avoid shattering and pre-harvest sprouting.

Rice: self-pollinated; paddy seed fields need isolation of about 3 m for certified seed; avoid fields with red rice and wild rice; dry to 12–13% moisture for storage.

Maize: cross-pollinated by wind; isolation distances are large (often 200–400 m or more depending on class); detassel the female parent before pollen shed in hybrid seed production and remove off-type tassels early each morning.

Pearl millet and sorghum: cross-pollinated; isolation of several hundred metres; in hybrid seed production, rogue fertile plants in the A line (sorghum) and control flowering overlap between A and R lines by staggered sowing.

Pulses (pea, chickpea, lentil): self-pollinated; small isolation distances; pea seed crops need support and timely harvest to avoid pod shattering; chickpea needs freedom from wilt and pod borer.

Oilseeds: rapeseed-mustard is cross-pollinated (isolation often 100–400 m); sunflower is insect-pollinated and needs isolation plus pollinator management; groundnut is self-pollinated and requires freedom from seed-borne aspergillus and aflatoxin risk.

Vegetable crops: brassicas (cabbage, cauliflower, radish) are cross-pollinated with self-incompatibility and need long isolation; tomato and chilli are largely self-pollinated but need isolation from other varieties; cucurbits are insect-pollinated and need isolation plus bee activity.

Hybrid seed production requires synchronised flowering: adjust sowing dates, use staggered planting of parental lines, and manage pollinators (e.g. honeybee colonies in sunflower and cucurbits) to maximise seed set.

Processing sequence: receiving and lot numbering → pre-cleaning (remove trash, straw, stones) → drying → cleaning and grading (air-screen cleaners, specific gravity separators) → treatment (fungicide/insecticide) → weighing and bagging → labelling and storage.

Seed moisture content is expressed on a wet-weight basis: MC% = [(wet weight − dry weight) ÷ wet weight] × 100; the oven method at 130 °C for 1–4 hours (or 103 °C for 17 hours) is the reference method.

Safe storage moisture: cereals generally 12–13%, oilseeds and pulses lower (about 8–10%); the rule of thumb is that each 1% reduction in moisture and each 5 °C reduction in temperature extends storage life.

Drying methods: sun drying on threshing floor or tarpaulin (cheap but weather-dependent), forced-air drying with heated or ambient air, and desiccant drying for small lots; drying temperature must stay below about 40–45 °C for most seed to protect viability.

Storage types: open storage for short-term farm seed, and controlled storage (cool, dry, insect-proof godowns) for foundation and breeder seed; long-term conservation uses cold stores at low temperature and low humidity.

Seed treatment: fungicides (e.g. carboxin, thiram) and insecticides (e.g. imidacloprid) applied as slurry or dry powder; bio-agents such as Trichoderma and Rhizobium are used for pulses; treated seed must be labelled as treated.

Storage pests: Sitophilus (weevils), Tribolium (flour beetle) and bruchids in pulses; control by fumigation (e.g. aluminium phosphide under gas-proof sheets), hermetic storage bags and maintaining low moisture.

Bagging and labelling: bags must be clean and of correct weight; label carries crop, variety, class, lot number, germination %, purity %, date of test, net weight and the certification tag for certified seed.

Purity analysis: a working sample is divided into pure seed, other crop seed, weed seed and inert matter; purity % = (pure seed weight ÷ total sample weight) × 100; results feed into the pure live seed calculation.

Germination test: prescribed number of seeds (commonly 400 in replicates of 100) placed on or in a substrate (paper, sand, soil) under specified temperature and light; normal seedlings counted at the prescribed first and final counts.

Tetrazolium (TZ) test: viable embryos stain red (living tissue reduces tetrazolium salt); used for quick viability estimates, dormant seeds, and seeds that are slow to germinate.

Moisture test: oven method (130 °C for 1 hour for cereals, 103 °C for 17 hours for oilseeds) or electronic moisture meters calibrated against the oven method.

Vigour tests: accelerated ageing (high temperature and humidity stress), electrical conductivity (leachate from damaged membranes), cold test (germination under cold, wet soil conditions) and seedling vigour index (germination % × seedling length).

Seed health testing: direct examination, blotter test, agar plate test and washing test to detect seed-borne fungi and bacteria; results determine treatment or rejection.

Certification process: application by grower → field inspection at prescribed stages → harvesting and processing → sample drawn by inspector → laboratory testing → issue of certification tag and label if standards are met.

Pure live seed (PLS) % = (purity % × germination %) ÷ 100; seed rate is adjusted by dividing the desired plant population by PLS to compensate for inert matter and dead seed.

In India, seed quality control is governed by the Seeds Act 1966 and the Seeds Rules 1968, with the Seeds (Control) Order 1983 regulating sale and licensing; state seed certification agencies implement certification.

Seed standards are minimum limits for germination %, purity %, moisture % and freedom from weeds and other crop seed; these differ by crop and by seed class (foundation stricter than certified).

The Indian Minimum Seed Certification Standards (IMSCS) prescribe field standards (e.g. maximum off-types, isolation distance) and seed standards (laboratory limits) for each crop and class.

Labelling requirements: every seed container must show crop, variety, class, lot number, germination %, purity %, moisture %, date of test, net weight, name and address of producer, and for certified seed the certification tag.

Truthfully labelled (TL) seed is sold on the producer's own declaration of quality without formal certification; certified seed carries a certification tag and has passed agency inspection and testing.

Seed import/export is regulated by plant quarantine laws; consignments need phytosanitary certificates, and imports of certain crops require prior permission and pest risk analysis.

The Protection of Plant Varieties and Farmers' Rights Act provides plant variety protection and recognises farmers' rights to save, use and exchange seed; registered varieties have enforceable rights.

International trade frameworks: ISTA rules for seed testing and labelling, OECD seed schemes for varietal certification of seed moving in international trade, and UPOV for plant variety protection.

Seed enterprise cost structure: seed production cost = land preparation + seed + fertiliser + plant protection + labour + irrigation + harvesting/threshing + processing + testing + certification fees + storage + transport; margin = sale price − total cost per quintal.

Break-even calculation: break-even yield or price = total fixed costs ÷ (price per unit − variable cost per unit); use it to decide whether a seed crop is worth growing in a given season.

Working capital cycle in seed business is long - sowing to sale spans a season or more - so cash-flow planning, credit lines and storage capacity must be arranged before sowing.

Quality assurance as a business asset: consistent germination and purity build dealer trust; rejected lots are a total loss, so invest in proper drying and storage rather than in extra volume.

Market channels: sale to state seed corporations and cooperatives on procurement contracts, direct dealer networks, farmer producer organisations, and e-commerce/agri-input retail; each has different margin and payment terms.

Record keeping: maintain field diary, source-seed invoices, inspection reports, processing and testing records, and sales registers; these support certification audits, loan applications and dispute resolution.

Occupational safety: pesticide handling requires gloves, mask, goggles and protective clothing; observe pre-harvest intervals and never eat or smoke during spraying; store chemicals locked away from seed and food.

Machine and dust safety in seed processing: guard belts and augers, use dust masks in cleaning and grading areas, and lock out power before clearing blockages; fumigation with phosphine requires gas-proof enclosures and trained operators only.