METHODS IN LEGUME-RHIZOBIUM TECHNOLOGY
by
P. Somasegaran and H. J. Hoben
University of Hawaii NifTAL* Project and MIRCEN*
Department of Agronomy and Soil Science
Hawaii Institute of Tropical Agriculture and Hunan Resources
College of Tropical Agriculture and Human. Resources
May, 1985
This document was prepared under United States Agency
for International Development (USAID) contract No.
DAN-0613-C-00-2064-00
* NifTAL and MIRCEN are acronyms for Nitrogen fixation
in Tropical Agricultural Legumes and Microbiological
Resources Center, respectively
FOREWORD
There is no doubt that in the near future the emerging biotechnology based on
genetic engineering and somatic cell fusion will contribute significantly to
solving agricultural problems.
Presently, however, so much of the available
technology, i.e., inoculum technology, is not being fully enough utilized in
agriculture.
It would be prudent to devote major efforts to their adoption.
Serious obstacles to adoption of modern technologies, especially in
developing countries, is the shortage of trained personnel.
It is,
therefore, essential for all development support projects to include a
training component.
This book is the culmination of several years of experience in training of
scientists and technicians from developing countries.
The six-week Training
Course, for which this book is intended, was developed at NifTAL and, in the
early years, taught there.
Subsequently, the course was taken to the field
and offered at host institutions in Africa, Asia and Latin America.
Somasegaran and Hoben have done a commendable job of drawing from their
experience with these courses.
They have compiled an “All You Ever Wanted To
Know About …” style book that is not only valuable to developing country
scientists, but also useful for technicians and graduate students starting
work with the legume/Rhizobium symbiosis.
B. Ben Bohlool
Professor, University of Hawaii
Director, NifTAL project
May, 1985
INTRODUCTION
The symbiosis between the root-nodule bacteria of the genus Rhizobium and
legumes results in the fixation of atmospheric nitrogen in root-nodules.
This symbiotic relationship is of special significance to legume husbandry as
seed inoculation with effective strains of Rhizobium can meet the nitrogen
requirements of the legume to achieve increased yields.
Obviously, such a
phenomenon is of world-wide interest because it implies lesser dependence on
expensive petroleum based nitrogen fertilizers for legumes.
In all regions of the world where food consumption exceeds production or
where nitrogenous fertilizer has to be imported, leguminous crops have a
special relevance.
Self-sufficiency for nitrogen supply and the high protein
and calorific values of food, forage and feed legumes make them increasingly
attractive.
Greater use of legumes can have a significant beneficial impact
in tropical countries where population increase and food production are most
out of balance, and where the purchasing power for imported fertilizers is
least adequate.
The University of Hawaii NifTAL Project was funded by the United States
Agency for International Development to promote greater use of symbiotic
nitrogen fixation through Legume-Rhizobium Technology.
An essential
component in NifTAL’s overall objective was specialized training in LegumeRhizobium Technology.
This strategy would provide the means of transferring
the techniques in Legume-Rhizobium Technology for the implementation of
viable research and development programs in nitrogen fixation in tropical
countries.
Training was initiated in 1976 when Professor J.M. Vincent prepared the first
course outline for NifTAL.
Since then, the authors have conducted similar
training courses in Hawaii, Kenya, Malaysia, Mexico, Thailand and India.
The
valuable experiences gained in these intensive six-week training courses led
the authors to identify and develop the key research and development
activities essential for Legume-Rhizobium Technology.
PREFACE
It was in 1970 that Professor J.M. Vincent published his excellent book
entitled “A Manual for Practical Study of Root-Nodule Bacteria.”
Unfortunately this book is out of print at the present time.
The motivation for this book of methods grew out of the ever-increasing role
of the Legume-Rhizobium symbiosis in agricultural production in tropical
countries where the benefits of this unique symbiosis can only be realized
through correct practices in Legume-Rhizobium Technology.
This book is designed for the practicing technologist to provide competent
technical support to research and development activities relevant to LegumeRhizobium Technology.
Teachers and students will also find this volume
useful in addressing the applied aspects of the Legume-Rhizobium symbiosis
especially when exercises are supported by well prepared lectures.
There are four sections to this book and they related the sequence of
activities which should be followed in Rhizobium research.
Each exercise is
structured to include all the steps required to accomplish the particular
experiment.
Certain activities in the exercise require a knowledge or a
source of information and this is given in the Appendix.
At the end of each
section are recommended journal articles and textbooks for more background on
principles or greater detail on methods.
In putting together this book, we
have indicated to the user by cross-reference that the various sections
support each other.
For example, the serological techniques in Section C are
not meant only for strain identification in nodules but also for checking
strain contamination in inoculant production and quality control.
It is hoped that this volume will serve as an instrument of self-instruction
since the skills can be acquired by careful practice of techniques.
Satisfactory completion of the exercises should impart to the user a good
working knowledge and competence in Legume-Rhizobium Technology.
The
exercises in this volume were tested successfully in all the NifTAL training
courses and intern training programs and we hope that this volume will be
useful in organizing similar courses by other institutions.
The authors would appreciate comments and suggestions for effecting further
revisions to improve this volume.
Padmanabhan Somasegaran
Heinz J. Hoben
May 1985
ACKNOWLEDGEMENTS
The authors are indebted to several colleagues who are specialists and who
contributed constructively in the review of preliminary versions of this
volume.
We gratefully acknowledge the support of professor J.M. Vincent who reviewed
and supplied us with detailed notes and comments for each exercise.
We are
indebted to him as the outline of this volume is based on a course outline
originally conceived by him while he was a consultant to the NifTAL Project.
The authors express their sincere thanks to Dr. J.C. Burton for his
encouragement and support.
His review, comments, and suggestions especially
in Section D were invaluable.
We wish to express our gratitude to Dr. J.
Halliday for his continued interest, encouragement and support in the
preparations of this volume.
The authors are indebted to the invaluable review support given by Drs. P.H.
Graham, D.H. Hubbell, B.B. Bohlool, P.W. Singleton, J.W. King, R.W. Weaver,
J.A. Thompson and L.A. Materon.
The authors wish to express their sincere
gratitude to Dr. Velitin Gurgun of the University of Ankara (Turkey) who did
an excellent review on the final version of this volume.
We appreciate all
participants of the NifTAL Training courses, intern trainees, and visiting
scientists whose comments and suggestions were invaluable in making this work
more comprehensive.
In the final analysis, the production of this volume was the result of
teamwork and support given to us by several NifTAL Project staff members.
We
express our sincere appreciation to all these helpful people.
They are Ms.
Princess Ferguson who handled all logistics pertaining to publication besides
editing; Ms. Judith Dozier for the painstaking checking, proofreading and
editing of the typed manuscripts; Mr. Keith Avery who patiently handled much
of the graphics and artwork; and Ms. Karean Zukeran and Ms. Mary Rohner for
the administrative and secretarial support.