Seed quality testing
- 2. What is seed quality? Defination of seed quality ● Quality seed is defined as varietal pure with a high germination percentage, free from disease and disease organisms, and with a proper moisture content and weight (Santos, 2007). ● Quality seed insures good germination, rapid emergence and vigorous growth. ● Ultimately, the sum of all the parameters contributing towards better performance of seed is termed as Seed Quality ● The quality of seed in our country is legally controlled by the Seeds Act, 1966 2
- 3. PARAMETRS TO ASSESS SEED QUALITY? ●Physical attributes: Number of damaged seed, inert matter, weed seed, diseased seed and near uniform seed size, comes under physical parameters and assessed through physical purity test ●Physiological attributes: Germination percentage, seed vigour and viability assessment depict through varied test germination test, tetrazolium test, accelerated ageing test, etc ●Genetically attributes: The other variety absence, high yielding ability, adaptability to local conditions and tolerant towards disease, pest and other biotic stress. The test determining these quality comes under genetic purity, cultivar purity test, etc ●Storability attributes: The storability of seed depend upon the moisture content, proper seed treatment and temperature of the environment and the test used is moisture test through moisture metre. 3
- 4. What is seed testing? Defination of seed testing: Seed testing is done to evaluate the quality attributes of seed lot, which is to be preceed in market for sale. 4 First seed testing laboratory opened by Father of seed technology, Fedrick Nobbe at Savang, Germany in 1869 International Seed Testing Association (ISTA) was established in 1924, with sole motive of “Uniformity in Seed Testing” In 1962, India became an accredited member of ISTA. In India, the Central Seed Testing Laboratory was setup during 1961-62 in Botany Division at the IARI, New Delhi, to analyze the quality of seed samples. The testing of seed samples was made obligatory under the Seed Act, 1996 for the purpose of certification and for low enforcement
- 5. Main Aim Behind Seed Testing? Seed testing is an important aspect for a seed programme in India ●Planting value determination ●Test the labelled seed standards ●Drying and processing need determination ●Probable cause and problem in seed quality could be assessed ●Discrimination of seed lot for consumer’s consumption at varied basic price THE PRIMARY AIM OF THE SEED TESTING IS TO OBTAIN ACCURATEAND REPRODUCIBLERESULTS REGARDING THE QUALITYSTATUS OF THE SEED SAMPLES SUBMITTED TO THE SEED TESTING LABORATORIES. SEED TESTING IS DETERMINING THE STANDARDS OF A SEED LOT VIZ. PHYSICALPURITY, MOISTURE, GERMINATIONAND ODV THEREBY ENABLINGTHE FARMING COMMUNITYTO GET QUALITYSEEDS . 5
- 6. SEED SAMPLING IS DONE Before Moving Towards Seed testing laboratory 6 A seed sample is obtained, which represent the seed lot Initially 2-4 primary sample is taken out, which are blended to form composite sample and further the submitted sample extracted out, which is send in laboratory for registration, office for primary reference and to producer for secondary reference In laboratory working sample is separate out for varied analysis such as purity analysis, germination test, seed health test, etc EQUIPMENT USED: For drawing sample from seed lot: Triers: Stick triers and Nobbe triers For getting desired quantity of true to the type of sample for submission in lab: Seed dividers: Boerner type divider (Conical divider), Soil divider (multiple slot divider) and Gamet divider (centrifugal dividers)
- 7. TYPES OF SEED SAMPLE 1) Primary Sample: A small portion taken from a lot at a particular stage with object of forming composite sample 2) Composite Sample: Combining and mixing all the primary sample taken from a lot and part of this send to lab for test 3) Submitted sample: A composite sample is usually larger in quantity. Sample reduced in quantity for being sent to the testing station 4) Working sample: Part taken from submitted sample in the laboratory, to subjected to quality test as describe in the ISTA 5) Guard Sample: When send to seed laboratory the seed is divided into three parts: First part: Send to laboratory; Second part: Send to trader; Third part: Retained in laboratory. And this third retained part is known as Guard sample
- 8. TYPES OF RECIEVED BY SEED TESTING LABORATORY 1) SERVICE SAMPLE: Sample received from farmers. The sample submitted to the central seed laboratory or to a state laboratory for testing, the results to be used as information for seeding, selling or labelling purposes. 2) CERTIFIED SAMPLE: Sample received from certification agency or officers. Certification sample means a sample of seed drawn by a certification agency or by a duly authorized representative of a certification agency established under section 8 or recognized under section 18 of the Seed Act. 3) OFFICIAL SAMPLE: Sample received from seed inspector to ascertain that the seeds meet minimum limit of specified quality 4) CHARGED SAMPLE: Sample received from NSC, SSC, Seed dealers, and other who are engaged in seed trade, who want to know the seed quality of the seed lot (All test are conducted)
- 9. 9 7. 6. 5. 4. 3. 2. 1. The seed sample received should be registered and assign test number To save timing for complete testing, the working samples are prepared for varied test The seed sample should be indented to moisture test first because it can add or loss original content due to outside condition Routine test are performed such as germination, vigour, viability ,purity, other variety test, diseased seed test, etc Other crop specific test performed Storage of guard sample at least for one year after submission of r=quality report Record maintenance is done for future tracing of data GUIDELINE TO MANAGE SEED SAMPLE EFFICIENTLY IN SEED TESTING LABORATORY
- 10. SEED TEST I. Moisture test II. Physical purity test III. Germination test IV. Seed Viability V. Seed Vigour VI. Diseased seed test VII. Genetic purity test VIII. Cultivar purity test 10
- 11. 11 Seed Moisture ORTHODOX SEED: 1. Desiccation tolerant; 2. Stored the seed for long time without lowering the viability; 3. Moisture content is 5% or low, e.g. cereals, pulses, oil seeds etc. RECALCITRANT SEED: 1. Desiccation sensitive; 2. They are viable only at high moisture content (15% or more), e.g. Coffee, mango, jack fruits etc. Several types of moisture meter are used for the testing of available moisture in seed, such as: Universal moisture meter, Steinlite moisture meter, Digital moisture meter, Infra red moisture meter, Karl fisher moisture meter, Agromatic mark- II, Koster moisture meter, 35 grain moisture meter, Cenco moisture meter, and Motomco moisture meter
- 12. Moisture Test A. Drying Direct Method: B. Low constant temperature oven method: Castor, Groundnut, cotton, brinjal, onion, Brassica, soyabean. Dried upto 17 hours C. High constant temperature oven method: All main crop except above, dried up to 4 hours in maize and 2 hour in other cereals. D. Indirect Method: Conductance types (Universal moisture meter) and Dielectric type M2-M3/ M2-M1 X 100 Where, M1: weight in gram of container and its cover M2: weight in gm of container, its cover and content before drying M3: weight in gm of container cover and content after drying
- 13. PHYSICAL PURITY ANALYSIS BY NUMBER BY WEIGHT MEASURED THROUGH PHYSICAL PURITY WORK BOARD (DIAPHANASCOPE) SUBMITTED SAMPLE INCLUDES OTHER THAN PURE SEED WEED SEED (WS) OTHER CROP SEED (OCS) OBJECTIONAL WEED SEED (OWS) DOCKAGE OTHER SEEDS Soil Particles Plant parts other than seeds Nematode Galls and Insects Seed of the allotted crop with half of its original size or without seed coat
- 14. PURITY TEST Purity (%) = Weight of pure seed ------------------------- X 100 Total weight of working sample It denotes the percentage of seeds (by weight) belonging to the variety under certification. Purity of seed is calculated on weight basis as follows: It is the percentage of a seed sample that would produce seedling of the variety under certification. This is also known as utility percentage of the seed. It is the function of purity and germination percentage of the seed sample. The real value of seed lot is determined as follows: REAL VALUE OF SEED Real value of seed (%) = Purity (%) X Germination (%) ----------------------------- 100 📌
- 15. Germination Test Germination percentage could be find out = Number seedling germinated X 100 Sum of normal, abnormal and un-germinated seed 15 TOP OF PAPER (TP) For small seeds BETWEEN PAPER (BP) For large seeds SAND (S) Pulse and gourd Seed germination on top of one layer of paper Seed germination between two or more layer of paper Seed are placed in the moist sand are covered with another layer of moist sand
- 16. 90% Maize 85% Wheat, Gram, Mustard 80% Rice, Horse gram, Niger, Sesame, True potato seed, Berseem, Lucerne 75% Pulse 70% Cabbage, Cauliflower, Brinjal, Onion, Radish, Tomato, Castor, Groundnut, Soybean, Sunflower 65% Cotton, Bhindi 60% Gourds, Carrot, Capsicum, Cucumber, Watermelon, Chillies Standard Minimum Germination Percentage
- 17. 17 PHYSICAL TEST PERFORMANCE TEST STRESS TOLERANCE BIOCHEMICAL TEST A. First count B. Speed of germination C. Seedling growth weight Cold test= corn Cool germination test= cotton Brick gravel test= cereals Pathogen infested soil Accelerated gravity test= cotton Wet/dry soil Seed size Physical soundness GADA TZ Respiration Mitochondria activity Membran Integrity Seed viability and vigour test
- 18. TETRA ZOLIUM TEST Number of half seeds stained red Viable seeds (%) = -------------------------------------------- X 100 Total number of half seeds / 18 1) This method determines the percentage of viable seeds, which may be expected to germinate. The chemical is 2, 3, 5-triphenyl tetrazolium chloride or bromide, which is colourless but develop red colour when reduced by living cell. In this method half seed containing embryo is placed in Petri dish and covered with 1% aqueous solution of tetrazolium chloride for 4 hours. 2) After that seeds are washed in tap water and count the number of seeds which get red stained. The per cent of viable seeds is computed as follows: 3) This method cannot be applied for those species that have very small seeds and embryo
- 19. Method for detection Fungal Pathogen Virus Pathogen Nematode associate pathogen Visual Inspection NAOH Test Microscopic examination Incubation Test Serology test Developing Seedling examination Controlled environment test Visual Inspection Microscopic examination Infectivity Test Serology test Electron Microscopy Test Developing Seedling examination under insect proof chamber Visual Inspection Microscopic examination ELISA Biochemical test Physiological test Seed Health test
- 20. 20 DETERMINATION OF GENETIC PURITY ODV TEST OTHER DITINGUISHING VARIETY TEST Determine genetic purity on basis of seed characters GOT TEST GROW OUT TEST Determine genetic purity on basis of plant morphological characters Genetic purity refers to analysis for detecting the existence of transgenic events or undesirable genetic varieties in seed. GENETIC PURITY
- 21. 21 Varieties that are grown for seed production should be periodically tested for genetic purity by conducting GOT to make sure that they are being maintained in true form. GOT test is compulsory for hybrids produced by manual emasculation and pollination and for testing the purity of parental lines used in hybrid seed production. GROW OUT TEST
- 22. VERIFICATION OF CULTIVARS 1. Fluorescent test for verification of oats varieties 2. Phenol colour test 3. Sodium Hydroxide test for verification of wheat varieties 4. Verification of sorghum varieties by KOH bleach test of seed 5. Identification of red rice by KOH test 6. Peroxidase activity test in Leguminaceae 7. Verification of Melilotus sp. by cupper sulphate ammonium test 8. Amonium Fluroscent test for Festuca sp
- 23. “ ” “THANKS TO ALL THE PATIENT READERS “ “A seed neither fears light nor darkness, but uses both to grow.”