Seed Technology & Plant Nursery BBO6T15

Syllabus topics (RTMNU)

• History of Seed Industry and its role
• Concept and Objective of Seed Technology
• Need and role of Seed Technology
• Objectives of seed processing
• Seed marketing: Structure and organization
• Seed identification of commercially important tree species

History of the Seed Industry and its Role

Seed is the basic input of agriculture — a good seed alone can raise yield by about 15–20%. The organised seed industry in India developed after Independence:

• 1957–61: hybrid maize programme of ICAR with the Rockefeller Foundation; Indian Seed Testing laboratory at IARI, New Delhi.
• 1963: National Seeds Corporation (NSC) set up to produce foundation and certified seed.
• 1966: Seeds Act passed (Seeds Rules 1968) — quality regulation and certification. Green Revolution with high-yielding wheat and rice varieties.
• 1969 onwards: Tarai Development Corporation; State Seed Corporations formed under the World Bank–aided National Seeds Project — e.g. Mahabeej (Maharashtra State Seeds Corporation, Akola, 1976).
• 1983: Seeds (Control) Order under the Essential Commodities Act — licensing of seed dealers.
• 1988: New Policy on Seed Development — liberal import of seeds; private and multinational companies grow.
• 2001–2002: Protection of Plant Varieties and Farmers' Rights Act, 2001; National Seeds Policy, 2002. Bt cotton approved 2002.
• Today: public sector (NSC, state corporations, SAUs) + a large private sector (e.g. Mahyco of Jalna, Nuziveedu, Rasi). A new Seeds Bill to replace the 1966 Act has been under discussion — check latest.

Role of the seed industry: supplies quality seed of improved varieties and hybrids; increases productivity and farmers' income; spreads new technology quickly; employment in production, processing and marketing; supports food security and exports.

Concept and Objectives of Seed Technology

Definition: Seed technology is the science that deals with methods of improving the genetic and physical qualities of seed — covering variety development, evaluation and release, seed production, processing, storage, testing, certification and marketing (Feistritzer, 1975).

Objectives: (1) rapid multiplication of improved varieties; (2) timely supply of quality seed; (3) assured high quality — genetic purity, physical purity, germination, vigour, freedom from disease; (4) reasonable price; (5) maintain genetic identity during multiplication; (6) safe storage and distribution.

Need and Role of Seed Technology

1. Farmers' saved seed loses purity and vigour over years; replacement with quality seed is needed (seed replacement rate).
2. New varieties and hybrids reach farmers only through an organised seed system.
3. Prevents spread of weeds, seed-borne diseases and pests.
4. Ensures uniform crop stand, maturity and quality produce.
5. Reduces seed rate and cost because of high germination.
6. Helps conserve genetic resources and maintains varietal identity.
7. Supports exports and the agro-industry.

Objectives of Seed Processing

Seed processing is the series of operations after harvest — drying, pre-cleaning, cleaning and grading, upgrading, treating, packing and labelling — to get clean, pure, healthy seed.

• Remove inert matter, weed seeds, other crop seeds and damaged, immature or light seeds.
• Grade seeds to uniform size for even sowing (by screens, air-screen cleaner, specific gravity separator, indented cylinder).
• Reduce moisture to safe level for storage.
• Treat seed with fungicide/insecticide or bio-agents (e.g. Trichoderma) to protect it.
• Pack and label correctly for marketing and certification.
• Minimise losses and keep germination high.

Seed Marketing: Structure and Organisation

Seed marketing is the movement of seed from producer to farmer at the right time, place and price.

Structure (channels):

• Public sector: NSC and state seed corporations sell through their own outlets, co-operative societies, Krishi Seva Kendras and state agriculture departments.
• Private sector: companies sell through distributors → dealers → retailers (licensed under the Seeds Control Order).
• Farmer-to-farmer exchange, community seed banks and FPOs.

Organisation of marketing: demand forecasting (crop area, seed replacement rate) → production planning → procurement from seed growers → processing and storage → pricing → promotion (field demonstrations, kisan melas, advertisements) → distribution → after-sales service. Features: seasonal demand, perishability (loss of viability), need for quality control and legal labelling.

Seed Identification of Commercially Important Tree Species

Likely exam questions

1. (Long, 8 marks) Trace the history of the seed industry in India and explain its role.
2. (Long, 8 marks) Define seed technology. Explain its objectives, need and role, and the objectives of seed processing.
3. (Short, 4 marks) Write a note on the structure of seed marketing.
4. (Short, 4 marks) Give identification features of seeds of any four tree species.
5. (Short, 4 marks) What are the objectives of seed processing?

Syllabus topics (RTMNU)

• Seed maturity test, Physical purity of seeds
• Seed germination
• Seed dormancy: Types, significance, mechanism (endogenous and exogenous) and factors regulating seed dormancy, methods of breaking seed dormancy
• Seed testing and quality control
• Seed viability, causes for loss of seed viability
• Seed vigour: Importance and underlying genetic mechanism; physiological basis of seed vigour and seed ageing

Seed Maturity Test and Physical Purity of Seeds

Seed maturity: the stage at which the seed has reached maximum dry weight (physiological maturity) with highest germination and vigour. Harvest is done a little later, at harvestable maturity, when moisture falls.

Signs/tests of maturity: change in colour of fruit/pod (green to yellow/brown), hardening of seed, formation of black layer at the base of maize kernels, seed moisture content (measured by oven method or moisture meter), dry weight becoming constant, ease of separation of seed from fruit, and germination test of samples.

Physical purity test (as per ISTA rules): a working sample drawn from the submitted sample is separated into four components and weighed:

1. Pure seed — seeds of the stated crop species (including broken pieces larger than half).
2. Other crop seed.
3. Weed seed.
4. Inert matter — soil, stones, chaff, broken pieces less than half.

Seed Germination

Definition: In seed testing, germination is the emergence and development of the seedling to a stage that shows it can grow into a normal plant under favourable conditions.

Requirements: water (imbibition), suitable temperature, oxygen, and in some seeds light.

Process: imbibition → activation of enzymes (amylase, protease, lipase) → breakdown of stored food → radicle emerges → plumule grows. Types: epigeal (cotyledons come above soil — bean, castor) and hypogeal (cotyledons stay below — pea, maize).

Germination test: 400 seeds (4 replicates of 100) placed on top of paper, between paper (roll towel) or in sand, kept in a germinator at fixed temperature. Seedlings are counted as normal, abnormal, hard, fresh ungerminated or dead. Germination % = normal seedlings ÷ seeds tested × 100.

Seed Dormancy: Types, Significance, Mechanism, Regulating Factors and Breaking Methods

Definition: Seed dormancy is the condition in which a viable seed does not germinate even when water, temperature and oxygen are favourable.

Types and mechanisms:

• Exogenous (seed-coat imposed): (a) hard, impermeable seed coat — water cannot enter (legumes, lotus); (b) coat impermeable to oxygen (Xanthium); (c) mechanically resistant coat preventing embryo growth; (d) inhibitors in coat or fruit.
• Endogenous (embryo-imposed): (a) rudimentary/immature embryo (orchids, Ginkgo); (b) physiological dormancy — embryo needs after-ripening; (c) chemical inhibitors such as abscisic acid (ABA), coumarin, phenolics; (d) light or temperature requirement.
• Also classed as primary (present at harvest) and secondary (induced later by unfavourable conditions).

Factors regulating dormancy: hormone balance (ABA promotes, gibberellins and cytokinins break), light (phytochrome — red light promotes, far-red inhibits in lettuce), temperature, oxygen, seed-coat nature, and moisture.

Significance: prevents germination in the wrong season (survival); prevents vivipary (sprouting on the plant) in cereals during rain; helps seed dispersal and storage; maintains seed bank in soil. But it causes uneven germination in crops and nurseries.

Methods of breaking dormancy:

1. Scarification — mechanical (rubbing on sandpaper, nicking) or chemical (concentrated H₂SO₄ soaking for hard seeds like Acacia).
2. Hot water soaking (teak, babul) or soaking in water for hours.
3. Stratification — keeping seeds in moist sand at low temperature (cold stratification) for weeks.
4. Treatment with gibberellic acid (GA₃), KNO₃, thiourea, ethylene.
5. Light exposure (red light) for light-sensitive seeds.
6. Leaching of inhibitors by washing; removal of seed coat; after-ripening by dry storage.

Seed Testing and Quality Control

Seed testing is the evaluation of seed quality to decide its value for sowing. It is done in notified seed testing laboratories as per ISTA (International Seed Testing Association) rules and Indian standards.

Steps/tests: sampling (primary → composite → submitted → working sample) → physical purity → other distinguishable varieties → germination → moisture content → seed health (diseases) → viability and vigour tests → genetic purity (grow-out test, molecular markers).

Quality control covers field inspection, processing checks, seed testing, certification, labelling and law enforcement (seed inspectors under the Seeds Act, 1966). Minimum standards for germination, purity and moisture are fixed for each crop.

Seed Viability and Causes of Loss of Viability

Viability: the capacity of a seed to remain alive and germinate. Tested by germination test or the tetrazolium (TZ) test: seeds soaked in 2,3,5-triphenyl tetrazolium chloride; living tissues reduce it to a red insoluble formazan (dehydrogenase activity), dead tissues stay colourless.

Causes of loss of viability: high seed moisture, high storage temperature and humidity, mechanical injury during threshing, attack by storage insects and fungi, immature harvest, poor genetic make-up, and ageing. Harrington's thumb rules: every 1% fall in seed moisture (between 5–14%) and every 5 °C fall in temperature (between 0–50 °C) doubles the storage life.

Seed Vigour: Importance, Genetic and Physiological Basis, Seed Ageing

Seed vigour is the sum of seed properties that determine the level of activity and performance of the seed during germination and seedling emergence over a wide range of field conditions (ISTA). Two lots with equal germination can differ in vigour.

Importance: quick and uniform field emergence, tolerance to stress, better storability, higher yield. Vigour tests: accelerated ageing test, seedling vigour index (germination % × seedling length), electrical conductivity test, cold test.

Genetic basis: vigour is a quantitative trait controlled by many genes; hybrid vigour (heterosis) gives stronger seedlings; seed size, food reserves and seed-coat traits are inherited.

Physiological basis and ageing: vigour depends on intact membranes, active enzymes, mitochondria, and food reserves. During ageing: lipid peroxidation by free radicals damages membranes → leakage of solutes (higher conductivity); loss of enzyme activity; damage to DNA, RNA and proteins; lower ATP; slow and abnormal germination and finally death. Good storage slows ageing.

Likely exam questions

1. (Long, 8 marks) Define seed dormancy. Describe its types, mechanism, regulating factors and methods of breaking dormancy.
2. (Long, 8 marks) Explain seed testing and quality control. Add notes on seed viability and seed vigour.
3. (Short, 4 marks) Explain the tetrazolium test.
4. (Short, 4 marks) How is physical purity of seed tested?
5. (Short, 4 marks) What is seed ageing?

Syllabus topics (RTMNU)

• Seed production of fruit crops, root crops and bulb crops with respect to land requirement, seedling / root production, nursery management, planting, breeding methods, seed harvesting and seed drying
• Seed identification: Method to distinguish crop and weed seeds
• Seed certification and legislation: Objectives and agencies involved; procedure and seed Acts
• Seed storage: Structure and their management
• Community seed bank

Seed Production of Fruit Crops, Root Crops and Bulb Crops

Seed production must keep genetic purity, so the main points are land, isolation, raising seedlings/roots, planting, roguing, harvesting and drying.

General requirements:

• Land: fertile, well-drained, free from volunteer plants (no same crop in the previous season unless the same variety), good irrigation.
• Isolation: distance from other varieties of the same crop to prevent cross-pollination and mixture; cross-pollinated crops (radish, carrot, onion) need large isolation, self-pollinated (tomato) less — as fixed in the Indian Minimum Seed Certification Standards.
• Roguing: removing off-type, diseased and weed plants at different stages.
• Seed class: breeder seed → foundation seed → certified seed.

1. Fruit crops (fruit vegetables such as tomato, brinjal, chilli; and fruit trees like papaya):

• Nursery: seeds sown on raised beds or pro-trays; healthy 4–6-week seedlings transplanted.
• Breeding methods: open-pollinated varieties maintained by selection; hybrids (tomato, brinjal, chilli) produced by hand emasculation and pollination, or male sterility.
• Harvesting: fully ripe fruits picked.
• Seed extraction: tomato — wet extraction by crushing and fermenting the pulp for 1–2 days (or acid method with HCl) to separate seeds from gel; seeds washed and dried. Brinjal and chilli — crushing/dry extraction. Papaya — sarcotesta removed by washing.
• Drying: in shade then sun to safe moisture (about 8%).

2. Root crops (radish, carrot, beetroot, turnip) — mostly biennial in temperate types:

• Seed-to-seed method: crop is left in the field to bolt and flower — cheap but no root selection.
• Root-to-seed method: roots are pulled, examined for true-to-type shape, colour and size, tops trimmed, and selected roots replanted ("stecklings") to produce seed — gives better purity; used for foundation seed.
• Cross-pollinated by insects — bee colonies help; isolation is very important.
• Seed stalks harvested when pods/umbels turn brown, dried, threshed and cleaned.

3. Bulb crops (onion, garlic):

• Onion — bulb-to-seed method: bulbs from the previous season are selected (true to type, firm, single-centred), stored, and planted in October–November (rabi); flowering umbels form; cross-pollinated by insects; umbels harvested in stages when 10–15% capsules show black seeds; dried and threshed. Seed-to-seed method is quicker but gives lower purity.
• Garlic does not set true seed — propagated by cloves.

Seed Identification: Distinguishing Crop and Weed Seeds

Weed seeds in seed lots reduce quality and spread weeds. Methods:

1. Visual/morphological examination with a hand lens or stereo-microscope — size, shape, colour, surface (hairs, ridges, wings), hilum position and seed-coat pattern.
2. Comparison with a reference seed herbarium and seed atlas.
3. Seedling morphology — growing the seeds and identifying seedlings.
4. Chemical tests — e.g. phenol test (colour of seed coat) for varietal differences; fluorescence under UV.
5. Biochemical and molecular methods — electrophoresis of seed proteins, DNA markers for exact identity.

Examples of weed seeds confused with crop seeds: Phalaris minor in wheat, wild oat (Avena fatua) in wheat/barley, Echinochloa in rice, Cuscuta (dodder) in lucerne and niger, Argemone in mustard (its oil causes epidemic dropsy).

Seed Certification and Legislation: Objectives, Agencies, Procedure and Seed Acts

Seed certification is a legally sanctioned system of quality control during seed multiplication and production to maintain genetic identity and purity.

Objectives: make quality seed of notified varieties available; maintain genetic purity; ensure minimum standards of germination, purity and health; protect farmers.

Agencies: State Seed Certification Agencies (e.g. Maharashtra State Seed Certification Agency, Akola), Central Seed Certification Board, Central and State Seed Committees, notified seed testing laboratories; internationally OECD schemes and ISTA.

Procedure:

1. Verification of seed source (tag and bill of breeder/foundation seed).
2. Application and registration of the seed plot.
3. Field inspections at different stages (isolation, off-types, diseases, weeds).
4. Supervision of harvesting and processing.
5. Sampling and seed testing in a notified laboratory.
6. Grant of certificate, tagging and sealing — foundation seed: white tag; certified seed: blue (azure) tag. (Breeder seed carries a golden-yellow label issued by the breeder; truthfully labelled seed carries an opal-green label.)

Seed legislation in India: Seeds Act, 1966 and Seeds Rules, 1968; Seeds (Control) Order, 1983; Environment (Protection) Act, 1986 and Rules 1989 (GM seeds); New Policy on Seed Development, 1988; PPV&FR Act, 2001; National Seeds Policy, 2002. A new Seeds Bill is under consideration — check latest.

Seed Storage: Structures and their Management

Aim: keep seed alive and vigorous from harvest to sowing.

Structures:

• Traditional: earthen pots, kothis, bamboo bins, mud structures (village level).
• Bags: jute, cloth, HDPE and moisture-proof polythene-lined bags for short storage.
• Metal bins and godowns/warehouses (Central and State Warehousing Corporations).
• Silos for bulk storage.
• Cold and dehumidified stores for valuable seeds (hybrids, vegetables, breeder seed); long-term gene banks at −18 °C.

Management: dry seed to safe moisture (about 8–12% for cereals, lower for oilseeds and in sealed packs); clean and treat seed; disinfest godowns; stack bags on wooden pallets away from walls with aisles; fumigation for insects; control rodents; keep good ventilation; regular inspection and periodic germination testing. Harrington's rule: temperature (°F) + relative humidity (%) should not exceed 100.

Community Seed Bank

A community seed bank is a local, farmer-managed store where seeds of traditional and local varieties are collected, conserved, multiplied and exchanged among farmers.

• Functions: conserve agro-biodiversity, provide seed after disasters, give access to locally adapted seed, keep traditional knowledge alive, reduce dependence on purchased seed.
• Working: farmers borrow seed and return a larger quantity after harvest; records of varieties are kept; seeds stored in pots, bottles or bins.
• Example: Rahibai Soma Popere of Akole (Ahmednagar), known as the "Seed Mother", runs a seed bank of indigenous varieties and was awarded the Padma Shri.

Likely exam questions

1. (Long, 8 marks) Describe seed production of root crops and bulb crops with reference to land, isolation, planting, harvesting and drying.
2. (Long, 8 marks) What is seed certification? Give its objectives, agencies and procedure, and list the seed Acts in India.
3. (Short, 4 marks) Distinguish between seed-to-seed and root-to-seed methods.
4. (Short, 4 marks) Write a note on community seed banks.
5. (Short, 4 marks) Give the management practices in seed storage.

Syllabus topics (RTMNU)

• Nursery management and operations: Layout design and nursery bed preparation
• Growth media preparation: Soil test, compost and potting mixtures
• Nursery operations: Potting, de-potting, re-potting, irrigation, and fertilization
• Management of nurseries: Weeding, hardening of plants, and plant protection (pest/disease control)
• Marketing and business management: Nursery registration, record maintenance, and economics of nursery development
• Pricing, packaging, and sales (online/offline)

Nursery Management and Operations: Layout Design and Nursery Bed Preparation

Nursery: a place where seedlings, saplings, grafts and cuttings of plants are raised and cared for until they are ready for planting in the field or for sale.

Site selection: level or gently sloping, well-drained land; assured good-quality water; near road and market; protection from strong winds and animals (fencing); partial shade available; electricity.

Layout design (plan on paper first): office and store; seed beds and propagation area; mother plant block (source of scions and cuttings); poly-house/shade-net house for propagation and hardening; potting yard and growing-media shed; compost pits; water tank and irrigation lines; sales area and parking; roads and paths; windbreak and fence around.

Nursery bed preparation:

1. Plough/dig soil to 20–30 cm, remove stones and weeds.
2. Make raised beds about 1 m wide, 15–20 cm high, of convenient length (3–5 m), with 30–50 cm paths — they drain well and prevent damping-off.
3. Mix well-rotted compost/FYM and sand to make the soil loose.
4. Soil sterilisation — soil solarisation (covering moist soil with transparent polythene in summer for 4–6 weeks), or fungicide drenching.
5. Sow seeds in lines, cover with fine soil, mulch with straw, water with a rose can.

Sunken beds are used in dry areas; pro-trays with cocopeat are used for vegetable seedlings.

Growth Media Preparation: Soil Test, Compost and Potting Mixtures

Soil test: soil samples are tested for pH (ideal 6–7.5), electrical conductivity (salinity), organic carbon and N, P, K so that the medium can be corrected (lime for acidic soil, gypsum for alkaline soil, fertilisers as needed).

Compost: decomposed organic waste (leaves, crop residue, dung) — improves structure, water holding and nutrients. Vermicompost (made by earthworms, e.g. Eisenia fetida) is rich and fine. Leaf mould and FYM are also used.

Potting mixtures: media should be light, porous, well-drained, able to hold water and nutrients, free from pests and weed seeds. Common mixtures:

Nursery Operations: Potting, De-potting, Re-potting, Irrigation and Fertilisation

• Potting: transferring seedlings or rooted cuttings into pots/polybags. Put a crock or stones over the drainage hole, add some mixture, place the plant at the same depth, fill around, press firmly, leave 2–3 cm space at top, water immediately and keep in shade for a few days.
• De-potting: removing a plant from its pot with the earth ball intact — invert the pot, tap the rim, and slide the plant out; done before planting or re-potting.
• Re-potting: shifting a pot-bound plant into a bigger pot with fresh mixture; old roots are trimmed; best done before the growing season.
• Irrigation: rose can and hose for small units; mist and fogging systems for propagation; drip and micro-sprinklers for pots; water in morning or evening; avoid waterlogging.
• Fertilisation: basal compost in the mixture, then water-soluble NPK (e.g. 19:19:19) and micronutrients through fertigation or foliar spray in small doses; bio-fertilisers (Azotobacter, PSB, mycorrhiza).

Management of Nurseries: Weeding, Hardening and Plant Protection

Weeding: regular hand weeding of beds and pots; mulching; using weed-free media and solarised soil; keeping paths clean.

Hardening: gradually exposing tender plants (especially tissue-culture plants and those from poly-houses) to outside conditions — more light, less water, lower humidity — over 2–4 weeks, so that they survive transplanting. Steps: high-humidity chamber → shade net (50%) → open nursery.

Plant protection:

• Diseases: damping-off (Pythium, Rhizoctonia), leaf spots, wilts, root rot — control by seed treatment (Trichoderma, carbendazim/thiram), soil solarisation, proper drainage, avoiding over-crowding.
• Pests: aphids, whiteflies, mealybugs, mites, termites, snails — yellow sticky traps, neem oil, need-based safe insecticides, removal of affected plants.
• Integrated Pest Management (IPM) and nursery hygiene (clean tools, quarantine of new plants).

Marketing and Business Management: Registration, Records and Economics

Nursery registration: fruit and commercial nurseries are registered/licensed with the state agriculture or horticulture department under state nursery laws (in Maharashtra, the fruit nursery regulation Act); the National Horticulture Board (NHB) gives accreditation/star rating to good nurseries. Registration builds customer trust and is needed for government supply orders.

Record maintenance: stock register (species, variety, number, age), mother-plant register, purchase and sales registers, labour and wage records, expenditure and cash book, pest/disease and spray records, customer and order records.

Economics — example: a nursery raises 10,000 saplings. Variable cost ₹8 per sapling (polybag, mixture, seed/cutting, labour) = ₹80,000; overheads (water, electricity, depreciation of shade-net) = ₹40,000; total cost ₹1,20,000. With 10% mortality, 9,000 saplings are sold at ₹25 = ₹2,25,000. Profit = ₹2,25,000 − ₹1,20,000 = ₹1,05,000; cost per saleable sapling = ₹1,20,000 ÷ 9,000 = ₹13.33.

Pricing, Packaging and Sales (Online/Offline)

Pricing: based on cost of production plus margin (cost-plus), competitors' prices, plant age/size, variety demand, season (monsoon demand is high), bulk discounts for government and landscaping orders.

Packaging: plants in polybags/pots with the earth ball intact; trays and crates for seedlings; wrapping with wet moss or newspaper for bare-root plants; labels with name, variety and care tips; sturdy cartons for courier.

Sales:

• Offline: nursery sales counter, weekly markets, agricultural exhibitions and kisan melas, supply to farmers, forest/social-forestry departments, gram panchayats, schools, housing societies and landscapers.
• Online: own website, WhatsApp catalogue, social media pages, e-commerce marketplaces; home delivery and courier for small plants; online payment by UPI.

Likely exam questions

1. (Long, 8 marks) Describe the layout design of a nursery and the operations of potting, de-potting, re-potting, irrigation and fertilisation.
2. (Long, 8 marks) Explain nursery registration, record maintenance, economics, pricing, packaging and sales of a nursery business.
3. (Short, 4 marks) What is hardening of plants?
4. (Short, 4 marks) Give the composition of potting mixtures.
5. (Short, 4 marks) How are damping-off and pests controlled in a nursery?