Seed Longevity and Storability
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Questions and Answers

What is the purpose of stratification in seed germination?

  • To apply growth regulators
  • To expose seeds to red light
  • To break seed dormancy by providing low temperature (correct)
  • To soak seeds in hot water

    • Which of the following seeds requires a brief period of incubation at 40 to 50°C before germination?

  • Lettuce (Lactuca sativa)
  • Paddy (Oryza sativa) (correct)
  • Apple
  • Apricot

    • What is the purpose of hot water treatment in seed germination?

  • To expose seeds to red light
  • To provide low temperature
  • To apply growth regulators
  • To break hard seed coats in legumes (correct)

    • Which of the following chemicals is used to break seed dormancy in oat, barley, and tomato?

    <p>Potassium nitrate</p> Signup and view all the answers

    What is the result of applying low levels of growth regulators like Gibberellins and Cytokinins to seeds?

    <p>Seed dormancy is broken</p> Signup and view all the answers

    Which of the following light treatments helps in breaking the dormancy of photoblastic seeds like lettuce (Lactuca sativa)?

    <p>Red light</p> Signup and view all the answers

    What is the purpose of presoaking seeds in 100 ppm GA3?

    <p>To break seed dormancy in sorghum</p> Signup and view all the answers

    What is the reason for endogenous dormancy in seeds?

    <p>Presence of germination inhibitors</p> Signup and view all the answers

    What is the relationship between seed size and injury?

    <p>Small seeds are less likely to be injured</p> Signup and view all the answers

    Which shape of seed provides more protection?

    <p>Spherical seeds</p> Signup and view all the answers

    What is the effect of provenance on seed longevity?

    <p>Provenance influences the longevity of seeds</p> Signup and view all the answers

    What is the most critical factor influencing seed longevity?

    <p>Seed moisture content</p> Signup and view all the answers

    What happens to seeds stored at high moisture content?

    <p>The loss of viability becomes very rapid</p> Signup and view all the answers

    Why is it necessary to dry seeds before storage?

    <p>To prevent mold growth and extreme desiccation</p> Signup and view all the answers

    What can lead to damage and loss of viability in seeds?

    <p>Micro flora, insects, and mites</p> Signup and view all the answers

    How can the activity of micro flora be controlled?

    <p>By controlling relative humidity, temperature, and moisture content</p> Signup and view all the answers

    What are the general requirements for seed germination?

    <p>Suitable substratum, adequate moisture, and favourable temperature</p> Signup and view all the answers

    What is the purpose of using soil as a substratum in germination testing?

    <p>To confirm the evaluation made by other methods</p> Signup and view all the answers

    What is the indicator dye used in the topographical tetrazolium test?

    <p>2, 3, 5 triphenyl tetrazolium chloride</p> Signup and view all the answers

    Which method of germination testing is generally used for large sized seeds?

    <p>Sand</p> Signup and view all the answers

    What is the result of incubating viable seeds in tetrazolium solution?

    <p>The seeds turn red</p> Signup and view all the answers

    Who developed the method of tetrazolium test?

    <p>Lakon</p> Signup and view all the answers

    What is the purpose of germination testing?

    <p>To determine seed viability</p> Signup and view all the answers

    What is the requirement for the methods of germination testing?

    <p>Based on Rules and Guidelines laid down by ISTA</p> Signup and view all the answers

    What is the principle behind the Topographical Tetrazolium Test?

    <p>Reduction of tetrazolium by dehydrogenase enzyme activity</p> Signup and view all the answers

    What is the time frame for estimating seed viability using the Topographical Tetrazolium Test?

    <p>within 12-20 hours</p> Signup and view all the answers

    What is an advantage of the Topographical Tetrazolium Test for dormant and slow germinating seeds?

    <p>The test is highly useful to assess their viability</p> Signup and view all the answers

    What is a limitation of the Topographical Tetrazolium Test?

    <p>All of the above</p> Signup and view all the answers

    What is the purpose of the Embryo-excision method?

    <p>To assess seed viability</p> Signup and view all the answers

    What is a characteristic of viable embryos in the Embryo-excision method?

    <p>They remain firm and slightly enlarged</p> Signup and view all the answers

    What is the purpose of the Ferric chloride test?

    <p>To detect mechanical damage</p> Signup and view all the answers

    What is the result of mechanical damage in the Ferric chloride test?

    <p>Seeds turn black</p> Signup and view all the answers

    What type of plants are excluded from the legislation?

    <p>Microorganisms</p> Signup and view all the answers

    What characteristic must a plant variety possess to be eligible for protection under the act?

    <p>Must be new, distinct, uniform and stable</p> Signup and view all the answers

    What is the purpose of compulsory licensing in the legislation?

    <p>In the public interest</p> Signup and view all the answers

    What restriction is placed on farmers in the legislation?

    <p>They cannot sell branded seeds for commercial purposes</p> Signup and view all the answers

    What is the purpose of the Seed Bill, 2004?

    <p>To regulate the seed industry</p> Signup and view all the answers

    What is the purpose of accreditation of Indian Council of Agricultural Research centres and private organizations?

    <p>To conduct performance trials</p> Signup and view all the answers

    What is the term coined by Mr. Hope Shand, the erstwhile Research Director of Rural Advancement Foundation International (RAFI), in 1998?

    <p>Terminator technology</p> Signup and view all the answers

    What is the characteristic of terminator seeds?

    <p>They prevent germination after one generation</p> Signup and view all the answers

    Study Notes

    Seed Injury and Longevity

    • Small seeds are less likely to be injured than large seeds
    • Spherical seeds provide more protection than flat or irregularly shaped seeds
    • Provenance (place of seed production) affects seed longevity, e.g., red clover seeds grown in Canada stored for four years with 80% germination, whereas seeds grown in England and New Zealand stored only for three years with 80% germination
    • Seed moisture content is the most important factor influencing longevity, with high moisture content decreasing storage life and low moisture content causing damage due to desiccation
    • Seeds should be dried to a safe limit for storability, suitable for the crop, before storage

    Microflora, Insects, and Mites

    • These organisms can lead to damage and loss of viability
    • Microflora activity is controlled by relative humidity, temperature, and moisture content of seeds
    • Treated seeds with fungicides can be stored for longer periods

    Temperature Treatments

    • Some seeds require exposure to chilling temperatures for germination, which can be achieved through stratification or artificial temperature control
    • Brief incubation at 40-50°C can break dormancy in some seeds, e.g., paddy (Oryza sativa)
    • Hot water treatment can break hard seed coats in legumes

    Light Treatments

    • Exposure to red light can break dormancy in photoblastic seeds, e.g., lettuce (Lactuca sativa)

    Treatments with Growth Regulators and Other Chemicals

    • Application of low levels of growth regulators like Gibberellins, Cytokinins, and Ethylene can break seed dormancy
    • Potassium nitrate (0.2%) and thiourea (0.5-3%) can also be used to break seed dormancy in certain crops

    General Requirements for Seed Germination

    • Suitable substratum, adequate moisture, and favorable temperature and light are required for germination
    • Crop-wise media or substrata, temperature, and duration of testing have been prescribed

    Methods of Germination Testing

    • Paper: Seeds can be tested for germination by placing them on, between, or in pleated strips of paper
    • Sand: Seeds can be tested for germination by placing them on or in sand
    • Soil: Germination can be tested using soil, but it is not recommended as a primary substratum due to inconsistent results

    Rapid Methods of Testing Seed Viability

    • Topographical Tetrazolium (TZ) test: Viable seeds turn red due to the presence of dehydrogenase enzyme activity when incubated in a tetrazolium solution
    • Advantages of TZ-test: quick and easy estimation of seed viability, useful for dormant and slow-germinating seeds, and seeds can be used for germination after the test
    • Disadvantages of TZ-test: difficulty in distinguishing between normal and abnormal seeds, and inability to detect microorganisms affecting germination

    Embryo-Excision Method

    • Embryos are excised from soaked seeds and incubated under normal conditions to assess viability
    • Germinating embryos are considered viable

    Ferric Chloride Test

    • Mechanical injured areas of legume seeds turn black when placed in a ferric chloride solution, allowing for rapid assessment of mechanical damage

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    Description

    Factors affecting seed longevity and storability, including seed size, shape, and provenance. Understand how these factors influence seed germination.

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