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Seed Testing: Principles and Practices

S. G. Elias
L. O. Copeland
M. B. McDonald
R. Z. Baalbaki
Copyright Date: 2012
Pages: 364
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  • Book Info
    Seed Testing
    Book Description:

    An essential reference for students, seed technologists, researchers, and seed industry personnel, this comprehensive guide outlines the most widely performed modern seed quality tests, explores the principles behind them, the history of seed testing, why seeds are tested and when, and sampling, sub-sampling, seed laboratory management, accreditation, and seed quality assurance programs. The authors describe statistical applications to seed testing and tolerances, and they provide a detailed morphological and structural description of seed formation and development. The book examines the testing of genetic traits and transgenic seeds, including DNA and protein genetic purity tests, and cultivar purity identification for conventional seeds. In addition to the most common seed purity and viability tests, tests for seed and seedling vigor, seed-borne diseases and seed moisture determination are also discussed.

    eISBN: 978-1-60917-317-3
    Subjects: Technology, Botany & Plant Sciences

Table of Contents

  1. Front Matter
    (pp. i-iv)
  2. Table of Contents
    (pp. v-viii)
    (pp. ix-x)
    Lawrence Copeland
    (pp. xi-xii)

    This book presents the most widely-performed tests in today’s seed quality testing world. It comprises thirteen chapters covering a wide range of tests used by seed testing laboratories, researchers and seed companies in the global seed industry. Since seed is the basic biological unit of all tests, a detailed morphological and structural description of seed formation and the development of both angiosperms and gymnosperms is provided in Chapter 2. Seedling structures are also illustrated and described.

    In covering each test, the book does not only show “how to” perform and evaluate the test, but also explains the principles of each...

  5. 1 Why Seeds are Tested, and When
    (pp. 1-10)

    Seed testing is the science of evaluating the quality of seeds to determine their value for planting. Though initially developed for field and garden seeds, seed testing is equally valuable for determining the seed quality of turf, flowers, herbs, shrubs, trees and native species.

    The term “seed quality” is loosely used to reflect the overall value of seed for planting; thus the role of seed as the basic unit of reproduction makes viability perhaps the most widely recognized aspect of seed quality. Information about the physical purity is probably the second most important factor for which seeds are tested. This...

  6. 2 Seeds and Seedlings
    (pp. 11-32)

    A seed has been described as a miniature plant packaged for storage and shipment. This is a very good definition, for a seed does contain a miniature plant in the form of the embryo, along with reserve food storage (endosperm, cotyledons, or other nutritive tissue) and a protective wrapping (seed coat).

    Seeds are well adapted for distribution and storage. Their structure enables them to be transported and disseminated by natural forces, such as wind, water, and animals, as well as agricultural practices. Many seeds possess dormancy factors which allow them to remain viable for long periods until conditions are suitable...

  7. 3 Sampling and Subsampling
    (pp. 33-42)

    No matter how carefully and accurately the analysis is performed, it can only show the quality of the sample tested/submitted. Thus, it is imperative that the sample be properly drawn and faithfully represent the quality of the seed lot from which it is taken. If taken with careless or biased procedures, all subsequent analyses may be meaningless and not representative of the actual quality of the seed lot. Any compromise or disregard of the principles of good sampling risks a bias in the results and does a disservice to both the producer and the consumer.

    Although preliminary or check samples...

  8. 4 Testing for Physical Purity
    (pp. 43-58)

    Along with germination, purity tests are one of the oldest and most common tests performed by seed analysts. Their purpose is to determine the physical composition of a seed lot by performing a detailed and precise separation on a small representativeworking sample. The procedure consists of separating the sample into four components (pure seed, other crop seed, weed seed, and inert matter) so the percent composition by weight of each may be determined. These components are shown in Figure 4.1.Pure seedis the portion of the working sample represented by the crop species for which the lot is...

  9. 5 Germination and Viability Testing
    (pp. 59-82)

    Seeds are tested for germination to determine how they will perform when planted in the field, the garden, or in a seedling nursery. This information is also needed for labeling and marketing purposes or to determine if a seed lot has been properly labeled when sold or offered for sale.

    Although seeds have been tested for germination for hundreds of years by critical gardeners and farmers, it has only been in the past 150 years that laboratory germination has been developed to provide farmers and other seed users assurance of the quality of seed produced on their own farms as...

  10. 6 Seedling Evaluation
    (pp. 83-116)

    The germination test is universally accepted by the seed trade, seed control officials, and certification agencies as an objective, reproducible means of evaluating seed quality. In seed laboratory practice, germination is defined “as the emergence and development from the seed embryo of those essential structures that, for the kind of seed in question, are indicative of the ability to produce a normal plant under favorable conditions” (AOSA, 2010). To meet these objectives, a germination test must provide a suitable environment for a specified duration of time to allow the “essential structures” to develop to a point where they can be...

  11. 7 Tetrazolium Testing
    (pp. 117-154)

    No seed laboratory can afford to operate and meet the needs of the modern seed industry without offering tetrazolium (TZ) testing services to its customers. Profits in the modern seed industry often demand rapid information about seed quality (viability) that can be provided only by the tetrazolium test. It is the classicquick testin that it provides a rapid determination of seed viability. It can also provide valuable insights into reasons for loss of viability, such as injury caused by frost, sprouting, chemical treatment, mechanical damage, structural abnormalities and other factors. Perhaps no other test can provide so many insights...

  12. 8 Seed and Seedling Vigor Testing
    (pp. 155-192)

    Seed vigor assessment provides important seed quality information regarding potential field performance (Powell, 1988; McDonald, 1994; 1998; Egli and TeKrony, 1995). A historical perspective of seed vigor has been chronicled (McDonald, 1993), reviews written (Chin, 1988; Roberts and Black, 1989; Hampton and Coolbear, 1990; TeKrony and Egli, 1993; McDonald, 1999), symposia convened (McDonald and Nelson, 1986, AOSA, 1993; van de Venter, 1995), and standardization issues confronted (McDonald, 1995). AOSA, ISTA and their respective Vigor Testing Committees continue to move forward with the development of new vigor testing methods and standardization of old vigor tests through the new AOSA Seed Vigor...

  13. 9 Genetic and Varietal Purity Testing
    (pp. 193-236)

    For the majority of primary agricultural crops, the seed remains the basic delivery system of genetic and molecular advances to the farmer. The increase in biotech-derived varieties, as well as the many other changes rapidly occurring in agriculture, has had a direct impact on variety testing. As seeds developed from biotechnology become more common, and as many of the newly released varieties differ in just one or a few genes, seed technologists are increasingly being challenged to develop ever more sophisticated and sensitive genetic purity tests. At the same time, some existing tests are being improved, others are limited to...

  14. 10 Seed Health Testing
    (pp. 237-256)

    Seedborne pathogens have been recognized as a major means of dissemination of plant pathogens since prehistoric times. Baker (1972) cites the following historically factual reports of associations between plant pathogens and seeds.

    Claviceps purpureaon rye (Hellig, 1699).

    Orobanche minorseeds mixed inViciaspp. seeds (Michelli, 1723).

    Anguina triticiin wheat seeds (Needham, 1743).

    Dust of bunt balls in wheat was the pathogenTilletiaspp. (Tillet, 1755).

    Seed pathology, however, did not emerge as a sub-discipline of plant pathology until the early part of the 20thcentury when seed analysts began to notice relationships between seedborne fungi that developed...

  15. 11 Seed Moisture Content Testing
    (pp. 257-270)

    Few factors are more important to the quality and function of seed than moisture content. Moisture content is associated with almost every aspect of seeds and their function, including their maturity, timing of harvest, susceptibility to mechanical injury during threshing or handling, longevity in storage, and injury due to heat, frost, fumigation, insects, and pathogens. Thus, moisture content is perhaps the most important factor which determines when seed is harvested, how it is handled after harvest, and how long it maintains its quality.

    Information in this chapter is largely taken from a review of measurement of seed moisture by Grabe...

  16. 12 Seed Laboratory Management, Accreditation, and Quality Assurance
    (pp. 271-292)

    A modern seed testing laboratory must have more than competent, well-trained analysts. Improved ergonomic equipment and innovative, efficient, and repeatable methods have become essential elements to deliver accurate, consistent, and timely results to the seed industry. All laboratories are confronted with ever-increasing pressures of delivering timely and accurate results to customers, while dealing with spiraling costs, government regulations and technical innovation. The seed industry, farmers, and other clientele are becoming more sophisticated, quality conscious, and demanding of better and faster services representing a wide range of different tests. This places ever-increasing pressures on seed laboratories far beyond those faced by...

  17. 13 Statistical Applications to Seed Testing
    (pp. 293-338)

    This section will explain the types of error that may occur in making a decision to accept or reject samples that represent seed lots. It also will discuss the sources of variation that may describe the differences between accuracy and precision, and the use of tolerance tables in seed testing.

    It is well-known that repeated tests on samples of the same seed lot do not necessarily produce identical results and that test results, even on the same sample, can be expected to vary to some extent. Variability in seed testing is accounted for through the use of tolerances which specify...

  18. Glossary
    (pp. 339-350)
  19. Index
    (pp. 351-354)
  20. Back Matter
    (pp. 355-355)