Table Of ContentGENETIC RESOURCES, CHROMOSOME ENGINEERING,
AND CROP IMPROVEMENT SERIES
Series Editor, Ram J. Singh
Volume 5
GENETIC RESOURCES,
CHROMOSOME
ENGINEERING, AND
CROP IMPROVEMENT
Forage Crops
edited by
Ram J. Singh
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Library of Congress Cataloging‑in‑Publication Data
Forage crops / editor, Ram J. Singh.
p. cm. ‑‑ (Genetic resources, chromosome engineering, and crop improvement series ; v. 5)
Includes bibliographical references and index.
ISBN 978‑1‑4200‑4739‑4 (alk. paper)
1. Forage plants. 2. Field crops. I. Singh, Ram J. II. Title. III. Series.
SB193.5.F67 2009
633.2‑‑dc22 2008043506
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Dedication
This book is dedicated to Emeritus Professor William F. Grant for his research in cytogenetics and
mutagenesis at the international level. His major research in birdsfoot trefoil (Lotus corniculatus)
utilizing interspecific hybridization with wild diploid species has shown a way to transfer genes
from wild species via diploid hybridization and amphidiploidy to produce an indehiscent cultivar.
He has carried out studies in Betula, Lotus, and Manihot using cytological, cytophotometric, chro-
matographic, and molecular techniques. He showed that mosaic virus-resistant plants of Manihot
esculentum were distinguishable from susceptible plants by chromatographic techniques. He pio-
neered the use of higher plant species (Allium cepa, Hordeum vulgare, Tradescantia, Vicia faba)
for monitoring and testing for mutagenic effects of environmental pollutants. He was elected a fel-
low of the AAAS and the Royal Society of Canada and has received an honorary DSc degree from
McMaster University. He was presented with the first lifetime achievement award for his scientific
contributions and service to the Genetics Society of Canada. He is a past editor of the Canadian
Journal of Genetics and Cytology (now Genome) and the Lotus Newsletter.
© 2009 by Taylor & Francis Group, LLC
Preface
What is a weed? A plant whose virtues have not been discovered.
Ralph Waldo Emerson (1803–1882)
Domestication of crops from weeds and the taming of wild animals have been an integral part
of human civilization since time immemorial. Herbivorous animals, including prehistoric animals,
grazed on leaves and succulent stems of weeds as well as leaves of shrubs and trees. Humans from
the Old World tamed herbivorous animals such as horses, cattle, sheep, goats, water buffaloes,
elephants, swine, domestic fowl, and various others, depending upon their needs. These animals
consume the vegetative parts of cereals and legumes after grains are harvested. However, many
crops of grass and of the legume family are used exclusively for livestock feed. These crops are used
for grazing or are harvested for green-chop feeding, silage, or hay. Grasses such as bermudagrass
and ryegrass are used for turf and forage.
Most of the forages belong to the grass family Poaceae (Gramineae) or the legume family
Fabaceae (Leguminosae). Six crops from the grass family (wheatgrass, wildrye grasses, Brachiaria,
bahiagrass, bermudagrass, and ryegrass) and three crops from the legume family (alfalfa, birdsfoot
trefoil, and clover) have been included in Forage Crops, volume 5 of the series Genetic Resources,
Chromosome Engineering, and Crop Improvement. Forage does not include plants cut or chopped
and fed to animals such as hay, silage, or freshly cut grass. These are known as fodders. However,
in developing countries, green pods are hand-picked from common bean, pea, cowpea, faba bean,
chickpea, lentil, mungbean, and azuki bean; green leaves and stems are used as fodder for livestock.
Goats love green leaves of pigeonpea—my personal observation while living in my hometown (the
village of Sirihara in the state of Uttar Pradesh) in India. Lupin is used for forage in Europe and
for grain in Australia. These crops have been covered in Grain Legumes, volume 1 of this series.
Volume 2 (Cereals) included chapters on wheat, rice, barley, oat, maize, sorghum, pearl millet,
rye, and man-made triticale. These are cultivated for grain. Straw is fed to livestock worldwide.
Soybean, groundnut, and sunflower—covered in Oilseed Crops, volume 4 of this series—were ini-
tially used as forage crops but are now grown for oil and meal.
The majority of forage crops (alfalfa, clover, birdsfoot trefoil, bermudagrass) were domesticated
in the Old World because they were fed to or allowed to be grazed on by tamed animals. By contrast,
the New World inhabitants, the American Indians, did not tame herbivore animals. More than two
thirds of wheatgrasses and wildrye grasses are native to Eurasia; from 22 to 30 grasses are consid-
ered native to North America and these are distributed throughout the vast prairies of the northern
Great Plains of the United States and Canada. Bahiagrass originated in tropical South America.
Several books on forage crops are in print:
Forage Crops (G. H. Ahlgren), published in 1956;
Theory and Dynamics of Grassland Agriculture (J. R. Harlan), published in 1956;
Grass and People (Charles Morrow Wilson), published in 1961;
Genetic Resources of Forage Plants (J. G. McIvor and R. A. Bray, eds.), published in 1983;
Forage Crops (D. A. Miller), published in 1984;
Pastures (R. H. M. Langer, ed.), published in 1990;
Genetic Resources of Mediterranean Pasture and Forage Legumes (S. J. Bennett and P. S. Cocks, eds.),
published in 1999;
Forages—An Introduction to Grassland Agriculture, volume I (R. F. Barnes, C. J. Nelson, M. Collins,
and K. J. Moore, eds.), published in 2003; and
Forages—The Science of Grassland Agriculture, volume II (R. F. Barnes, C. J. Nelson, K. J. Moore,
and M. Collins, eds.), published in 2007.
vii
© 2009 by Taylor & Francis Group, LLC
viii Preface
The latter two books are in their sixth editions. However, none of the books mentioned here or else-
where has attempted to assemble the comprehensive information on genetic resources, gene pools,
cytogenetics, and varietal improvement that has been compiled in Forage Crops.
The intensive varietal improvement of forage crops for high yield and improved nutritional qual-
ity (or elimination of antinutritional quality) and high palatability are the primary breeding objec-
tives of various national programs (public institutions and private industries). Centro Internacional de
Agricultura Tropical (CIAT) has a mandate for collection, maintenance, and varietal improvement of
Brachiaria. Most genetic improvement of forage crops has been accomplished by conventional breed-
ing assisted by germplasm resources, cytogenetics, plant pathology, entomology, agronomy, cell and
tissue cultures, and molecular biology. Three forage legumes (Medicago truncatula, Lotus japonicus,
and Trifolium pretense) are considered model crops for molecular genetics and genome sequencing.
The introductory chapter of this book (Chapter 1) summarizes landmark research done in the
nine forage crops discussed in this book. Successive chapters provide a comprehensive account of
the origin of each crop, its genetic resources in various gene pools, basic and molecular cytogenetics,
conventional breeding, and the modern tools of molecular genetics and biotechnology. Appropriate
germplasm collections can be an excellent resource for genetic enhancement of various traits in for-
age crops and for broadening their genetic bases. The genetic bases of forage crops are extremely
narrow. In view of the narrow genetic base of oilseed crops, three gene pools (GPs) have now been
identified by scientists for each crop: primary (GP-1), secondary (GP-2), and tertiary (GP-3). The
recommendation is to use GP-2 and GP-3 resources in producing widely adapted varieties. The utili-
zation of these resources (wide hybridization) in producing high-yielding cultivars that are resistant
to abiotic and biotic stresses and have improved nutritional qualities is discussed in this book.
Eight major forage crops—alfalfa (Chapter 2), wheatgrass and wildrye grasses (Chapter 3),
bahiagrass (Chapter 4), Brachiaria (Chapter 5), birdsfoot trefoil (Chapter 6), clover (Chapter 7), ber-
mudagrass (Chapter 8), and ryegrass (Chapter 9)—are included in this book. Other minor grasses
and legumes are not included in this volume.
Each chapter has been written by experts in the field. I am extremely grateful to all the authors
for their outstanding contributions and to the reviewers of all the chapters. I have been fortunate
to know them both professionally and personally, and our communication has been very cordial
and friendly. I am thankful to Byron Byrson for identifying several forage crop researchers and
encouraging them to contribute their expertise to this book. I am particularly indebted to Govindjee,
William Grant, and Joseph Nicholas for their comments and suggestions.
This book is intended for scientists, professionals, and graduate students whose interests center
upon genetic improvement of crops in general and major forage crops in particular. This book is
also intended as a reference for plant breeders, taxonomists, cytogeneticists, germplasm explorers,
pathologists, entomologists, physiologists, agronomists, molecular biologists, food technologists,
and biotechnologists. Graduate students in these disciplines who have an adequate background in
genetics, as well as other researchers interested in biology and agriculture, will also find this volume
a worthwhile source of reference. I sincerely hope that the information assembled here will help in
the much needed genetic amelioration of forage crops to feed livestock because an ever expanding
global population depends on livestock. I anticipate that this book will enhance awareness of rais-
ing livestock in open pastures and feeding them grasses grown in nature rather than meals enriched
with hormones and other animal by-products.
I end this preface with a quotation from Jack R. Harlan (1917–1998):
The wider crosses not only take patience but determination, commitment, and, frequently, a good deal
of skill and ingenuity. (Crop Science 16:329–333, 1976)
Ram J. Singh
Urbana-Champaign, Illinois
© 2009 by Taylor & Francis Group, LLC
The Editor
Ram J. Singh, MSc, PhD, is an agronomist–plant cytogeneticist in the Department of Crop
Sciences, at the University of Illinois at Urbana-Champaign. He received his PhD degree in plant
cytogenetics under the guidance of the late Professor Takumi Tsuchiya from Colorado State
University, Fort Collins, Colorado. He has benefited greatly from the expertise of and working
association with Drs. T. Tsuchiya, G. Röbbelen, and G. S. Khush.
Dr. Singh conceived, planned, and conducted pioneering research related to cytogenetic problems
in barley, rice, rye, oat, wheat, and soybean. Thus, he isolated monotelotrisomics and acrotrisomics
in barley, identified them by Giemsa C- and N-banding techniques, and determined chromosome
arm-linkage group relationships. By using pachytene chromosome analysis, Dr. Singh identified
12 possible primary trisomics in rice and determined chromosome-linkage group relationships. In
soybean [Glycine max (L.) Merr.], he established genomic relationships among species of the genus
Glycine and assigned genome symbols to all species. Dr. Singh constructed, for the first time, a
soybean chromosome map based on pachytene chromosome analysis that laid the foundation for
creating a global soybean map. By using fluorescent in situ hybridization, he confirmed the tetra-
ploid origin of the soybean.
Dr. Singh developed a methodology to produce fertile plants with 2n = 40 chromosomes from
an intersubgeneric cross between soybean and a perennial wild species, Glycine tomentella (2n =
78); this invaluable invention has been awarded a patent (US-2007-0261139-A1). He has published
70 research papers in reputable international journals, including the American Journal of Botany,
Chromosoma, Critical Review in Plant Sciences, Crop Science, Euphytica, Genetics, Genome,
Journal of Heredity, Plant Breeding, The Nucleus, and Theoretical and Applied Genetics. In
addition, he has summarized his research results by writing 13 book chapters. His book Plant
Cytogenetics (first edition in 1993 and second edition in 2003) is widely used for teaching gradu-
ate students. He has presented research findings as an invited speaker at national and interna-
tional meetings.
Dr. Singh is a member of the Crop Science Society of America and the American Society of
Agronomy, the chief editor of the International Journal of Applied Agricultural Research (IJAAR),
and editor of Plant Breeding. In 2000 and 2007, he received the Academic Professional Award
for Excellence: Innovative & Creativity from the Department of Crop Sciences, the University of
Illinois at Urbana-Champaign. He was invited to become a visiting professor by Dr. Kiichi Fukui
(Osaka University, Osaka, Japan; October 12, 2004–January 12, 2005) and Dr. Gyuhwa Chung
(Chonnam National University, Yeosu, Chonnam, South Korea; October, 2006). Dr. Singh is an
editor for the series entitled Genetic Resources, Chromosome Engineering, and Crop Improvement
and has published Grain Legumes (volume 1), Cereals (volume 2), Vegetable Crops (volume 3), and
Oilseed Crops (volume 4). Forage Crops (volume 5) and Medicinal Crops (volume 6) are expected
in print by 2009 and 2010, respectively.
ix
© 2009 by Taylor & Francis Group, LLC
Contributors
Carlos A. Acuña Minoru Niizeki
Agronomy Department Faculty of Agriculture and Life Science
University of Florida Laboratory of Plant Breeding and Genetics
Gainesville, Florida Hirosaki University
Hirosaki, Aomori-ken, Japan
Reed E. Barker
Grass Genomic Testing
Maria Suely Pagliarini
Oregon State University
Departamento de Biologia Celular e Genética
Corvallis, Oregon
Universidade Estadual de Maringá
Maringá, Brazil
Gary R. Bauchan
USDA-ARS
Electron and Confocal Microscopy Unit G. Pederson
Soybean Genomics and Improvement Lab USDA-ARS Plant Genetic Resources
Beltsville, Maryland Conservation Unit
University of Georgia
Ann R. Blount Griffin, Georgia
North Florida Research and Education
Center—Marianna K. Quesenberry
University of Florida Department of Agronomy
Marianna, Florida University of Florida
Gainesville, Florida
Cacilda Borges do Valle
EMBRAPA/CNP Gado de Corte
Ram J. Singh
Campo Grande, Brazil
Department of Crop Sciences, National
Soybean Research Laboratory
William F. Grant
University of Illinois
Department of Plant Science
Urbana, Illinois
McGill University, Macdonald Campus
Montreal, Canada
Charles M. Taliaferro
Kevin B. Jensen Plant and Soil Science Department
USDA-ARS Forage and Range Research Lab Oklahoma State University
Utah State University Stillwater, Oklahoma
Logan, Utah
Scott Warnke
Geunhwa Jung
USDA/ARS
Department of Plant, Soil, and Insect Sciences
Floral and Nursery Plants Research Lab
University of Massachusetts
Beltsville, Maryland
Amherst, Massachusetts
J. B. Morris M. L. Wang
USDA-ARS Plant Genetic Resources USDA-ARS Plant Genetic Resources
Conservation Unit Conservation Unit
University of Georgia University of Georgia
Griffin, Georgia Griffin, Georgia
xi
© 2009 by Taylor & Francis Group, LLC
xii contributors
Richard R.-C. Wang Yanqi Wu
USDA-ARS Forage and Range Research Lab Plant and Soil Sciences Department
Utah State University Oklahoma State University
Logan, Utah Stillwater, Oklahoma
© 2009 by Taylor & Francis Group, LLC
Contents
Preface..............................................................................................................................................vii
The Editor .........................................................................................................................................ix
Contributors ......................................................................................................................................xi
Chapter 1
Landmark Research in Forage Crops ................................................................................................1
Ram J. Singh and William F. Grant
Chapter 2
Alfalfa (Medicago sativa ssp. sativa (L.) L. & L.) ..........................................................................11
Gary R. Bauchan
Chapter 3
Wheatgrass and Wildrye Grasses (Triticeae) ..................................................................................41
Richard R.-C. Wang and Kevin B. Jensen
Chapter 4
Bahiagrass ........................................................................................................................................81
Ann R. Blount and Carlos A. Acuña
Chapter 5
Biology, Cytogenetics, and Breeding of Brachiaria ......................................................................103
Cacilda Borges do Valle and Maria Suely Pagliarini
Chapter 6
Birdsfoot Trefoil (Lotus corniculatus L.) ......................................................................................153
William F. Grant and Minoru Niizeki
Chapter 7
Clover .............................................................................................................................................207
J. B. Morris, G. Pederson, K. Quesenberry, and M. L. Wang
Chapter 8
Bermudagrass ................................................................................................................................229
Yanqi Wu and Charles M. Taliaferro
Chapter 9
Ryegrass .........................................................................................................................................275
Scott Warnke, Reed E. Barker, and Geunhwa Jung
Appendix .......................................................................................................................................287
Index ..............................................................................................................................................291
xiii
© 2009 by Taylor & Francis Group, LLC
1
ChaPTEr
Landmark research in Forage Crops
Ram J. Singh and William F. Grant
ConTEnTs
1.1 Introduction .................................................................................................................................1
1.2 Importance of Forage Crops .......................................................................................................2
1.3 Establishment of International and National Programs ..............................................................3
1.4 Gene Pools of Forage Crops ........................................................................................................3
1.4.1 Primary Gene Pool ..........................................................................................................4
1.4.2 Secondary Gene Pool ......................................................................................................5
1.4.3 Tertiary Gene Pool ..........................................................................................................5
1.4.4 Quaternary Gene Pool.....................................................................................................5
1.5 Germplasm Resources for Forage Crops ....................................................................................5
1.6 Germplasm Enhancement for Forage Crops ...............................................................................6
1.6.1 Breeding Forage Crops for High Yield ...........................................................................7
1.6.2 Breeding Forage Crops for Antinutritional Elements .....................................................7
1.6.3 Breeding Apomictic Forage Crops .................................................................................8
1.6.4 Development of Breeding Methods ................................................................................8
1.7 Conclusions .................................................................................................................................8
References ..........................................................................................................................................9
1.1 InTroDuCTIon
Herbivore animals have preferred to graze certain grasses, shrubs, and leaves of trees since
prehistoric times. Humans selected, domesticated, cultivated, and harvested grains from the cere-
als, legumes, oilseed, and other crops for their use and simultaneously tamed the animals, including
ruminant livestock, by feeding them vegetative parts also known as straw (roughages). Furthermore,
domesticated animals graze on wastelands, on fallows, under trees and groves, and in pastures.
Pasture crops include alfalfa, clover, birdsfoot trefoil, wheatgrass, wildrye grasses, bermudagrass,
brachiaria, and ryegrass, as well as other minor crops such as vetches (Vicia spp.) and brassicas.
The classic example of a cultivated crop is alfalfa, a forage legume that has been cultivated since
1,300 b.c. Its importance to feeding horses is described in Greek literature between 440 and 322
b.c. (Chapter 2). With the establishment of human civilization, animals started to be confined by
the erection of barriers (stones, hedges) followed by fencing. Humans started to raise crops, tend to
animals, and cultivate pastures—a triangular symbiotic relationship since the beginning of human
civilization. Freshly cut or uncut grasses, legumes, and other crops were converted into hay or silage
1
© 2009 by Taylor & Francis Group, LLC
