Table Of ContentSeed Testing
S. G. Elias
Oregon State University
L. O. Copeland
Michigan State University
M. B. McDonald
Ohio State University
R. Z. Baalbaki
Department of Food & Agriculture
California
Michigan State University Press
East Lansing
Copyright © 2012 by Sabry G. Elias, Lawrence O. Copeland, Miller B. McDonald, and Riad Z. Baalbaki
i
The paper used in this publication meets the minimum requirements of ANSI/NISO Z39.48-1992
(R 1997) (Permanence of Paper).
Michigan State University Press
East Lansing, Michigan 48823-5245
Printed and bound in the United States of America.
18 17 16 15 14 13 12 1 2 3 4 5 6 7 8 9 10
Library of Congress Cataloging-in-Publication Data
Seed testing : principles and practices / Sabry G. Elias ... [et al.].
p. cm.
Includes bibliographical references and index.
ISBN 978-1-61186-039-9 (cloth : alk. paper) 1. Seeds—Testing. I. Elias, Sabry G. (Sabry Gobran)
SB117.S382 2012
631.5'210287—dc23
2011029990
Cover design by Charlie Sharp, Sharp Designs, Lansing, Michigan
Book design by L. O. Copeland
G
Michigan State University Press is a member of the Green Press Initiative and is committed to
developing and encouraging ecologically responsible publishing practices. For more information about
the Green Press Initiative and the use of recycled paper in book publishing, please visit
www.greenpressinitiative.org.
Visit Michigan State University Press at
www.msupress.org
Contents
Preface ................................................................................................................................................ix
Introduction ........................................................................................................................................xi
Chapter 1. Why Seeds are Tested, and When .........................................................................................................1
Seed Testing Organizations .................................................................................................................3
A Rich Heritage - Classic Contributions and Memorable Milestones ................................................6
Chapter 2. Seeds and Seedlings .............................................................................................................................11
Angiosperm Seed ..............................................................................................................................12
Gymnosperm Seed ............................................................................................................................17
Classification of Embryos (Both Angiosperms and Gymnosperms) ................................................22
Seed Unit Structure ...........................................................................................................................23
Seed Morphology ..............................................................................................................................25
Germination - Transition from Seed to Seedling ..............................................................................27
Seedlings ...........................................................................................................................................27
Chapter 3. Sampling and Subsampling ..................................................................................................................33
The Sampling Process .......................................................................................................................34
Subsampling in the Laboratory .........................................................................................................38
Chapter 4. Testing for Physical Purity ...................................................................................................................43
Equipment and the Working Environment .......................................................................................44
Subdividing - Obtaining the Sample for Testing ...............................................................................48
The Purity Separation .......................................................................................................................48
Noxious Weed Seed Examination and Other Bulk Exams ................................................................50
Pure Seed ...........................................................................................................................................50
Weed Seed ........................................................................................................................................53
Special Purity Tests and Procedures .................................................................................................54
Uniform Blowing Procedure .............................................................................................................56
Chapter 5. Germination and Viability Testing ........................................................................................................59
Seed Selection, Preparation, and Planting .........................................................................................59
Substrata for Germination Tests ........................................................................................................60
Germination Chambers .....................................................................................................................68
Duration of Test .................................................................................................................................70
Evaluation of Seedlings .....................................................................................................................71
Dormancy ..........................................................................................................................................72
Causes of Loss of Germinability .......................................................................................................76
Tests for Detecting Damage of the Seed Coat ...................................................................................78
Chapter 6. Seedling Evaluation ...............................................................................................................................83
Overview of Seedling Evaluation .....................................................................................................83
Factors Affecting Seedling Evaluation ..............................................................................................89
Seedling Evaluation of Different Representative Families ...............................................................92
Chapter 7. Tetrazolium Testing .............................................................................................................................117
Principles .........................................................................................................................................117
Applications ....................................................................................................................................118
Limitations ......................................................................................................................................120
Facilities, Equipment, and Supplies ................................................................................................120
General Procedures .........................................................................................................................121
Preparation of Dry Seed Before Moistening ...................................................................................121
Moistening .......................................................................................................................................121
Preparation for Staining ..................................................................................................................122
Staining with TZ Solution ...............................................................................................................127
Preparation for Evaluation ..............................................................................................................128
Evaluation .......................................................................................................................................129
Tetrazolium Methods for Various Representative Families ............................................................131
The Tetrazolium Test as a Vigor Test ..............................................................................................150
Accuracy of Tetrazolium Test Results .............................................................................................150
Chapter 8. Seed and Seedling Vigor Testing .......................................................................................................155
History of Seed Vigor Testing .........................................................................................................155
Seed Vigor Test Benefits .................................................................................................................160
Standardization of Seed Vigor Tests ...............................................................................................162
Classification of Seed Vigor Tests ...................................................................................................165
Vigor Tests - Principles and Procedures ..........................................................................................169
Chapter 9. Genetic and Varietal Purity Testing ...................................................................................................193
Part 1: DNA and Protein Genetic Purity Tests ................................................................................196
Analytical Methods Analyzing DNA-Marker Techniques ..........................................................197
Protein Electrophoresis ................................................................................................................201
Bioassay Tests to Detect Genetic Traits.......................................................................................204
Part 2: Varietal Identification Tests Based on Morphological, Chemical, Growth Habits
and Other Characteristics ................................................................................................................208
Seed and Seedling Morphology ...................................................................................................208
Chemical (Quick) Tests ...............................................................................................................208
Cytological Tests ........................................................................................................................218
Growth Chamber Testing .............................................................................................................220
Disease Resistance Tests..............................................................................................................231
Chapter 10. Seed Health Testing ..........................................................................................................................237
Seed Health Testing Methods ..........................................................................................................239
Serology ..........................................................................................................................................248
DNA Techniques .............................................................................................................................252
Standardization of Seed Health Testing Methods ...........................................................................254
Chapter 11. Seed Moisture Content Testing ........................................................................................................257
Oven-Drying Methods ....................................................................................................................259
Distillation Methods ........................................................................................................................260
Solvent-Extraction Methods ............................................................................................................261
Electronic Moisture Meters .............................................................................................................261
Other Methods .................................................................................................................................262
The Air-Oven Method .....................................................................................................................263
Chapter 12. Seed Laboratory Management, Accreditation, and Quality Assurance .......................................271
Preliminary Considerations .............................................................................................................272
Equipment and Facilities .................................................................................................................276
Types of Tests ..................................................................................................................................277
Record-Keeping - State and Federal Regulations ...........................................................................281
Seed Analyst Training .....................................................................................................................281
Certification of Analysts ..................................................................................................................282
Proficiency and Referee Programs ..................................................................................................283
Research and Development .............................................................................................................283
Financial Support ............................................................................................................................284
Quality Assurance ...........................................................................................................................285
Laboratory Accreditation ................................................................................................................286
Chapter 13. Statistical Applications to Seed Testing .........................................................................................293
Section One - Tolerances .................................................................................................................293
Application of Tolerances in Seed Testing .....................................................................................295
Tolerances for Purity Tests ..............................................................................................................298
Tolerances for Incidental Seed Contamination with Noxious Weeds .............................................300
Tolerances for Germination Tests ....................................................................................................302
Tolerances for the Tetrazolium Test ................................................................................................304
Tolerances for Electric Conductivity and Accelerated Aging Tests ................................................305
Tolerances for Seed Moisture Determination ..................................................................................305
AOSA Tolerances for Fluorescence Tests of Lolium and 400 - 1,000-Seed Separations
in Purity Analyses ...........................................................................................................................305
Section Two - Seed Lot Heterogeneity............................................................................................307
Appendix: Tolerance Tables ............................................................................................................313
Glossary ..................................................................................................................................................................339
Index ........................................................................................................................................................................351
PrEfACE
This book has been planned for many years. It began when it became clear that the USDA Handbook No.
30 “Testing Agricultural and Vegetable Seeds,” which was developed in 1952, did not have the advanced
tests to meet the needs of today’s sophisticated seed industry. Although Handbook No. 30, which was
developed under the leadership of Dr. O. L. Justice, who for many years was the head of the USDA Seed
Testing Laboratory at Beltsville, MD, represented the only comprehensive coverage of seed testing for
generations of seed analysts, developing an updated book was earnestly needed. This need was initially
met by the development of a series of handbooks published as three-ring binders by the AOSA. While this
concept of handbooks was useful, many analysts and others involved in seed quality evaluation continued
to be interested in a comprehensive book in one or two volumes. This need was in part met by the 2008
publication “Seed Purity and Taxonomy” by Baxter and Copeland. The authors of this book, “Seed Testing:
Principles and Practices,” hope that this publication will further address the remaining need and represent
a comprehensive, state-of-the-art coverage of seed testing as it is practiced in 2011 and beyond. As such,
it should be a valuable resource for beginning and experienced seed technologists, as well as students and
members of the seed industry.
This book is a cooperative effort of four people who have contributed the wealth of their collective
experience and interest in seed science and technology on the subject of seed testing. Lawrence Copeland,
Professor Emeritus, Michigan State University has had a long-term interest in seed testing and development
of educational materials covering this subject. He originally conceived the scope of this book and enlisted
the aid of his long-time collaborator, Miller McDonald, Professor Emeritus, Ohio State University, who
contributed chapters on germination (Chapter 5), vigor (Chapter 6), and varietal purity testing (Chapter 7).
A fourth chapter (Chapter 10) on seed health testing was contributed by Denis McGee, Professor Emeritus,
Iowa State University. Notwithstanding the scope and vision for the manuscript, the book took second
place to other projects, such as retirements, other writing projects, research, etc. Finally, two former gradu-
ate students with Professor Copeland at Michigan State University, after extensive experience in academic
and seed industry professions, brought to this proposed book their talents and wealth of experiences and
positions at two state-of-the-art seed testing laboratories. Dr. Sabry G. Elias, Associate Professor in the
Crop and Soil Science Department at Oregon State University, teaches seed science and technology to
undergraduate and graduate students and is also the director of Special Testing at OSU Seed Laboratory.
Previously, he spent time in the private seed industry and Alabama A & M University. In addition, Dr. Elias
is a talented artist and many of his drawings appear in this book. Dr. Riad Baalbaki has been Senior Botanist
at the California State Seed Laboratory since 2006, after spending fifteen years as an Associate Professor
at the American University of Beirut, Lebanon, where he was active in teaching and research. Besides their
respective abilities and experiences in their present positions, Dr. Elias and Dr. Baalbaki are involved in
many committees and activities of the Association of Official Seed Analysts. This extraordinary collection
of unique experience and abilities has contributed to making this book best reflect the most current seed
testing technologies as they are practiced in the United States as well as internationally.
The authors sincerely thank Kimberly Collar, quality manager at Oregon State University Seed
Laboratory, for her assistance with preparing the manuscript, improving many of the illustrations and
reviewing Chapter 12.
Lawrence Copeland
Professor Emeritus, Michigan State University
East Lansing, Michigan
ix
