Organic Crop Breeding E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 704

Veröffentlichungsjahr: 2011

Beschreibung

Organic Crop Breeding provides readers with a thorough review of the latest efforts by crop breeders and geneticists to develop improved varieties for organic production. The book opens with chapters looking at breeding efforts that focus on specific valuable traits such as quality, pest and disease resistance as well as the impacts improved breeding efforts can have on organic production. The second part of the book is a series of crop specific case studies that look at breeding efforts currently underway from around the world in crops ranging from carrots to corn. Organic Crop Breeding includes chapters from leading researchers in the field and is carefully edited by two pioneers in the field. Organic Crop Breeding provides valuable insight for crop breeders, geneticist, crop science professionals, researchers, and advanced students in this quickly emerging field.

Leseprobe

Contents

Cover

Title Page

Copyright

Dedication

Contributors

Foreword

Preface

Acknowledgments

Section 1: General Topics Related to Organic Plant Breeding

Chapter 1: Organic Crop Breeding: Integrating Organic Agricultural Approaches and Traditional and Modern Plant Breeding Methods

Introduction

How Different Are Organic Farming Systems?

Consequences for Cultivar Requirements

From Cultivar Evaluation to Organic Seed Production and Plant Breeding Programs

The History of Organic Crop Breeding in Europe and the United States

Perspectives and Challenges for Breeding for Organic Agriculture

Conclusion

Chapter 2: Nutrient Management in Organic Farming and Consequences for Direct and Indirect Selection Strategies

Introduction

Availability of Nutrients in Organic Farming

Roots: The Hidden Potential

Even Greater Complexity: Plant-Microbe-Soil Interactions

Importance of Selection Environments

Breeding Strategies

Chapter 3: Pest and Disease Management in Organic Farming: Implications and Inspirations for Plant Breeding

Introduction

Plant Protection in Organic Farming

Key Target Areas of Plant Breeding for Organic Plant Protection

Breeding Goals for Ecological Plant Protection

Plant Breeding Approaches Directly Targeting Pests or Diseases

Plant Breeding Approaches with Indirect Effects on Plant Health

Discussion and Conclusions

Chapter 4: Approaches to Breed for Improved Weed Suppression in Organically Grown Cereals

Background

Crop Competitiveness Against Weeds

Crop Traits Involved in Weed Suppression

Selection of Traits and Their Evaluation in Plant Breeding Programs

Selection Strategies

Understanding Crop-Weed Interactions to Assist Plant Breeding

Concluding Remarks and Wider Perspectives

Chapter 5: Breeding for Genetically Diverse Populations: Variety Mixtures and Evolutionary Populations

Introduction

Benefits of Genetic Diversity for Organic Agriculture

On-Farm Conservation of Useful Genetic Diversity

Breeding Strategies

Conclusion

Chapter 6: Centralized or Decentralized Breeding: The Potentials of Participatory Approaches for Low-Input and Organic Agriculture

Introduction

Centralized and Decentralized Breeding: Definitions

What Can Be Decentralized in Breeding and Why?

Participatory Approaches

PPB: A Single Term Yielding Different Approaches

Some Examples of PPB for Organic and Low Input Agriculture in Southern Countries

Some Examples of PPB for Organic and Low Input Agriculture in Northern Countries

General Conclusions and Limits of PPB Approaches in Organic Farming

Chapter 7: Values and Principles in Organic Farming and Consequences for Breeding Approaches and Techniques

Introduction

Arguments Against Genetic Engineering

Organic Basic Principles

Toward Organic Breeding

From Values to Criteria: Evaluation of Breeding Techniques

How to Deal with Varieties Bred with Non-compliant Techniques?

Toward Appropriate Standards to Promote Organic Plant Breeding

Discussion and Challenges for Organic Plant Breeding

Chapter 8: Plant Breeding, Variety Release, and Seed Commercialization: Laws and Policies Applied to the Organic Sector

Introduction

The Developments of Plant Breeding and the Emergence of Seed Laws

Variety Registration

Seed Quality Control and Certification

Special Needs for Organic Agriculture

A Recent Development in Europe: Conservation Varieties

Intellectual Property Rights and Plant Breeding

Discussion

Conclusions

Section 2: Organic Plant Breeding in Specific Crops

Chapter 9: Wheat: Breeding for Organic Farming Systems

Introduction

Methods

Traits for Selection in Organic Breeding Programs

A Case Study for EPB: Lexi’s Project

A Case Study for Breeding within a Supply Chain Approach: Peter Kunz and Sativa

Conclusion

Chapter 10: Maize: Breeding and Field Testing for Organic Farmers

Introduction

What Kind of Maize do Organic Farmers Want?

Are There Viable Alternatives to Single Cross Hybrids?

Testing and Using Alternative Hybrids

Are There Benefits for Breeding under Organic Conditions?

For Which Traits Is It Necessary to Test under Organic Conditions?

Choice of Parents for Breeding Programs

Breeding Programs

Future Directions

Chapter 11: Rice: Crop Breeding Using Farmer-Led Participatory Plant Breeding

Introduction

MASIPAG and Participatory Rice Breeding

Beyond PPB: Farmer-Led Rice Breeding

The Breeding Process

Outcomes of the MASIPAG Program

Outlook

Chapter 12: Soybean: Breeding for Organic Farming Systems

Introduction

Agronomic Characters

Seed Quality Features

Considerations on Breeding Methods

Chapter 13: Faba Bean: Breeding for Organic Farming Systems

Purposes of Breeding and Growing Faba Bean

Genetic and Botanical Basics of Breeding Faba Bean

Methodological Considerations

Traits To Be Improved in Faba Bean Breeding

Open Questions, Need for Action

Chapter 14: Potato: Perspectives to Breed for an Organic Crop Ideotype

Introduction

Required Cultivar Characteristics

Introgression Breeding and Applied Techniques

Participatory Approach: An Example from the Netherlands

Outlook

Chapter 15: Tomato: Breeding for Improved Disease Resistance in Fresh Market and Home Garden Varieties

Introduction

Botanical and Genetic Characteristics of Tomato

Rationale for Breeding Tomatoes within Organic Systems

Breeding Needs with Focus on Organic Production

Case Studies: Breeding for Late Blight Resistance in Europe and North America

Outlook

Chapter 16: Brassicas: Breeding Cole Crops for Organic Agriculture

Introduction

Rationale for Breeding within Organic Systems

Plant Biology

Traits Needed for Adaptation to Organic Production

Consideration of Breeding Methods

A Farmer Participatory Broccoli Breeding Program

Outlook

Chapter 17: Onions: Breeding Onions for Low-Input and Organic Agriculture

Introduction

Robust Onion Cultivars

Breeding for Improved Nutrient Acquisition

Mycorrhizal Symbiosis and Product Quality

Conclusion

Index

This edition first published 2012 © 2012 by John Wiley & Sons, Inc.

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Library of Congress Cataloging-in-Publication Data

Organic crop breeding / editors, Edith T. Lammerts van Bueren, James R. Myers. p. cm. Includes bibliographical references and index. ISBN 978-0-470-95858-2 (hard cover : alk. paper) 1. Plant breeding. 2. Organic farming. I. Lammerts van Bueren, E. T. (Edith T.) II. Myers, James Robert. SB123.O74 2012 631.5′2–dc23 2011036447

A catalog record for this book is available from the British Library.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Dedication

We dedicate this book to all organic growers whose knowledge, vision, and wisdom has helped us to see the marvellous complexities of organic plant breeding through farmers’ eyes.

Contributors

Silvio AguirreCIPRES Pueblo Nuevo, NicaraguaMatt ArterburnDepartment of Biology Washburn University Topeka, KS, USABrian BakerThe Organic Center, P.O. Box 20513, Boulder, CO 80308, USA; formely with Alfred State College Sustainability Institute Alfred, NY, USANils-Øve BertholdssonSwedish University of Agricultural Sciences Department of Plant Breeding and Biotechnology Alnarp, SwedenRiccardo BocciItalian Association for Organic Agriculture (AIAB) Roma, ItalyHenriette BurgerKWS SAAT AG Einbeck, GermanySalvatore CeccarelliICARDA Aleppo, SyriaVéronique ChableInstitut National de la Recherche Agronomique (INRA) Sciences for Action and Development (SAD-Paysage) Rennes, FranceMicaela ColleyOrganic Seed Alliance Port Townsend, WA, USAJulie C. DawsonDepartment of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA; formerly with Institut National de la Recherche Agronomique (INRA) Gif sur Yvette, FranceDominique DesclauxINRA Mauguio, FranceThomas F. DöringThe Organic Research Centre, Elm Farm Hamstead Marshall, UKMaria R. FinckhEcological Plant Protection Group Faculty of Organic Agricultural Sciences University of Kassel Witzenhausen, GermanyLamiae GhaoutiDepartment of protection, production and vegetal biotechnology, Institut Agronomique et Vétérinaire Hassan II, B.P. 6202 Rabat-Instituts Madinat Al Irfan C.P 10101, Morocco; formerly with Georg-August-Universität Crop Science Department Göttingen, GermanyIsabelle GoldringerInstitut National de la Recherche Agronomique (INRA) Gif sur Yvette, FranceWalter A. GoldsteinMandaamin Institute, Elkhorn, Wisconsin; formerly with Crops and Soils Research Michael Fields Agricultural Institute East Troy, WI, USAMajor M. GoodmanDepartment of Crop Science North Carolina State University Raleigh, North Carolina, USAIsabell HildermannResearch Institute of Organic Agriculture (FiBL) Ackerstrasse Frick, SwitzerlandSteve P. HoadScottish Agricultural College West Mains Road Edinburgh, UKBernd HorneburgDepartment of Crop Sciences Georg-August-University of Göttingen Göttingen, GermanyKristina HubbardOrganic Seed Alliance Port Townsend, WA, USARonald C.B. HuttenWageningen UR Plant Breeding Wageningen University and Research Centre Wageningen, The NetherlandsSteve S. JonesWashington State University Research and Extension Center Mt. Vernon, WA, USAUlrich KöpkeInstitute of Organic Agriculture University of Bonn Bonn, GermanyFrank J. KutkaSeed We Need Project Dickinson, ND, USAThomas W. KuyperDepartment of Soil Quality Wageningen University Wageningen, The NetherlandsEdith T. Lammerts van BuerenLouis Bolk Institute Driebergen, The Netherlands; and Wageningen UR Plant Breeding Wageningen University and Research Centre Wageningen, The NetherlandsJacques LançonCirad c/o ICRAF Nairobi, KenyaWolfgang LinkGeorg-August-Universität Göttingen Crop Science Department 37075, Göttingen, GermanyNiels LouwaarsPlantum, P.O. Box 462, 2800 AL Gouda, The Netherlands; formerly with Centre for Genetic Resources The Netherlands (CGN) Wageningen University and Research Centre Wageningen, The NetherlandsLaurie McKenzieDepartment of Horticulture Oregon State University Corvallis, OR, USACharito P. MedinaMASIPAG Laguna, PhilippinesMichelle MenkenMinnesota Crop Improvement Association St. Paul, MN, USA Department of Agronomy and Plant Genetics University of Minnesota St. Paul, MN, USAMonika MessmerResearch Institute of Organic Agriculture (FiBL) Ackerstrasse Frick, SwitzerlandKevin MurphyDepartment of Crop and Soil Sciences Washington State University Pullman, WA, USAJames R. MyersDepartment of Horticulture Oregon State University Corvallis, OR, USAJohn NavazioOrganic Seed Alliance Port Townsend, WA, USADaniel NeuhoffInstitute of Organic Agriculture University of Bonn Bonn, GermanyMarco PautassoCenter for Synthesis and Analysis on Biodiversity, French Foundation for Research on Biodiversity. Montpellier Cedex, France; formerly with Conservation Science Group Department of Zoology Cambridge University Cambridge, UKLinda M. PollakGuthrie Center, IA, USA Formerly with USDA-ARS Corn and Soybean Unit Iowa State University Ames, Iowa, USARichard C. PrattDepartment of Horticulture and Crop Science Ohio Agricultural Research and Development Center The Ohio State University Wooster, OH, USAMaaike RaaijmakersBionext, Laan van Vollenhove 3221, 3706 AR Zeist, The NetherlandsZed RengelSoil Science and Plant Nutrition School of Earth and Environment The University of Western Australia Crawley, WA, AustraliaWalter SchmidtKWS SAAT AG Einbeck, GermanyOlga E. ScholtenWageningen UR Plant Breeding Wageningen University and Research Centre Wageningen, The NetherlandsMargaret E. SmithDepartment of Plant Breeding and Genetics Cornell University Ithaca, NY, USAKristian Thorup-KristensenDepartment of Agriculture and Ecology, University of Copenhagen Taastrup, DenmarkMarjolein Tiemens-HulscherLouis Bolk Institute Driebergen, The NetherlandsGilles TroucheCIRAD, UMR AGAP Avenue Agropolis Montpellier, FranceJohann VollmannBOKU – University of Natural Resources and Life Sciences Vienna Department of Crop Sciences Vienna, Konrad Lorenz Str. 24, 3430 Tulln, AustriaRoeland E. VoorripsWageningen UR Plant Breeding Wageningen University and Research Centre Wageningen, The NetherlandsEva WeltzienInternational Crops Research Institute for the Semi-Arid Tropics (ICRISAT) Bamako, MaliKlaus P. WilboisFiBL Deutschland e.V. Research Institute for Organic Agriculture Frankfurt am Main, GermanyMartin S. WolfeThe Organic Research Centre, Elm Farm Hamstead Marshall, UK

Foreword

This book is a long overdue addition to the plant breeding literature. Until now, what has been written on the subject of breeding for organic production systems has been scattered among many journals and conference proceedings. These other sources seldom, if ever, combine both philosophy and practical experience, and often the older sources have focused on one species or a group of allied species. This volume overcomes both weaknesses. It is rich in both practical knowledge and philosophy of breeding plants for organic systems. Field and vegetable crops and self-pollinated and cross-pollinated species are thoroughly discussed.

While many will seek out this volume in their desire to become practitioners of breeding for organic agriculture, all those interested in plant breeding should read it to understand the theory and philosophy as well as the legal and structural aspects that underlie breeding for organic systems. Undoubtedly some readers will question some ideas, but many will be exposed to new perspectives. And this is precisely why this book is so important.

Increasingly, breeding for organic agriculture is gaining attention in the public and private sectors in both Europe and in the United States. This has come about through the realization that organic production systems usually represent a different environment from conventional systems, and due to potential genotype × system interactions, varieties not adapted to a specific production system may not be the best performers in that system. Many of the methods used in organic plant breeding have been developed in poorer countries under low-input conditions without a seed production infrastructure. The sharing of innovative methods among these different areas has opened an exciting time in the breeding for organic and sustainable systems.

The editors have organized a thoughtful review on the topic of organic plant breeding and tapped as authors the leaders in the field. The book is split into two sections: Section 1, General topics related to organic plant breeding and Section 2 Organic plant breeding in specific crops. The first section will be of interest to all those interested in plant breeding. After an introductory chapter, the next three chapters cover the unique environmental challenges presented by organic systems and various ways plant breeders have risen to meet those challenges. The next four chapters are perhaps the most provocative of the book and are sure to generate discussion among students of plant breeding. Chapters and deal with technical challenges that should be of interest to all breeders and those are the development of genetically diverse cultivars that can respond to evolutionary pressures and the dichotomy of centralized versus decentralized research and extension systems. Chapter  tackles values and principles in organic breeding and will be eye-opening to many. Chapter  discusses intellectual property (IP), germplasm ownership, and commercialization issues that constrain organic plant breeding. Given the much smaller and decentralized nature of organic plant breeding efforts the IP and distribution mechanisms that have been developed for large commercial ventures don’t fit, often constrain, and sometimes eliminate the ability of organic plant breeding to be successful. Section 2 with nine chapters on organic breeding of specific crops will be a valuable resource to breeders of these and other allied crops.

The editors hailing from Europe and the United States represent the two regions where organic plant breeding has shown the greatest advances. They have assembled a team of authors that reflects this diversity, and in the process of writing these chapters have fostered cross pollination among the regions. The result is a cosmopolitan approach to the subject.

The field is rather new, and we are seeing an exponential increase in the literature as the first round of studies is completed. This book establishes the baseline for a growing discipline within plant breeding and is designed to contribute to furthering knowledge and innovation in the field of organic plant breeding.

William F. Tracy Madison, Wisconsin

Preface

Organic crop breeding is a relatively young and growing discipline described as either plant breeding for organic agriculture or plant breeding under organic conditions, acknowledging the organic principles that underlie this field. Both approaches are captured in this book as “organic crop breeding.”

Research into organic plant breeding has, to a large extent, been focused on cereal crops, but for many other crops this field is still in its infancy. This book brings some balance, in that it includes several crop-specific book chapters, of which cereals are part, but other groups representing legumes, cole crops and various vegetable crops are also covered.

While it is well established that organic production systems represent different growing environments compared to conventional systems, and that genotype x production system interaction is an important consideration, we do not have adequate knowledge of what components of an organic system are most important and what varietal traits allow optimal adaptation to such a system. The first section of the book provides some illumination on this subject in its coverage of general topics of organic plant breeding.

This book will be able to be read independently by those with some background in plant breeding; however, in general, this book will not discuss basic breeding principles, but will focus on the specific issues that are of importance when considering breeding for the organic sector. The book is divided into two sections covering (1) general topics related to organic crop breeding and (2) crop-specific topics. The general topics section discusses the basic organic principles and their consequences for plant breeding, and reviews the state-of-the-art of current breeding research.

Chapter 1 is an introductory chapter showing how organic breeding is a cross between organic agricultural approaches and traditional and modern plant breeding techniques and discusses the basic differences between organic, conventional high- and low-input agriculture, and the history of organic plant breeding in the United States and Europe.

Chapter 2 discusses the consequences of nutrient management in organic farming systems for crop improvement and includes complex issues such as breeding for nutrient efficiency and root system improvement.

Chapter 3 focuses on the fact that organic farming refrains from chemical pest management. Although resistance breeding is a familiar topic to most breeders, this chapter describes where and in which way organic management can reduce pressure of pest and diseases, where crop breeding needs to contribute, and in which ways innovative approaches should be further explored.

Chapter 4 deals with a relatively new topic for breeders on approaches to breed for improved weed suppression – departing from the experience in organically grown cereals, but with application to other crops. Chapter 5 addresses the central issue of biodiversity in organic agriculture. Biodiversity is considered a vital tool in creating higher levels of resilience in farming systems. The chapter describes strategies to exploit genetic diversity using cultivar mixtures and evolutionary breeding approaches.

Chapter 6 discusses the potentials of participatory approaches for low-input and organic agriculture in Western contexts, and arises from the fact that organic plant breeding is an economic niche for the commercial breeding industry that can profit from the experience of organic growers.

Chapter 7 describes the “Values and principles in organic farming and consequences for breeding approaches and techniques.” It underscores the importance of understanding the origins of organic agriculture, its world-view, and the rationale for the rejection of certain modern plant breeding techniques. Overall, it provides a framework in which organic plant breeding can develop. Chapter 8 discusses the consequences of the current “Laws and policies that govern plant breeding and seed supply” and recommends modifications that support the emerging organic breeding sector.

The second half of the book provides applied examples of the general approaches discussed in chapters 1 through 8 in specific crops. Research groups and breeders were invited to describe the most relevant traits for their crop species, including their experience in breeding for organic farming systems and perspectives on traits required for better adapted cultivars. For this book, crops were selected based on whether experience in breeding for organic systems was available. The crops included: Wheat, maize, rice, soybean, faba bean, potato, tomato, crucifers, and onion. They each give either a general review of the state-of-the-art and breeding perspectives, and/or emphasize a specific breeding approach, and included some examples of current organic breeding programs.

With this compilation, we seek to provide subject matter of interest to students, researchers, and other professionals from universities and institutes related to breeding research and those in plant breeding and seed companies. It is our hope and expectation that this book will be relevant to organic and conventional agriculture alike, and that it will facilitate the search for more sustainable farming systems for the twenty-first century and beyond.

Edith T. Lammerts van Bueren James R. Myers

Acknowledgments

The idea for this book came from Justin Jeffryes, executive editor at Wiley-Blackwell. The editors of this book gratefully took up his invitation and are thankful for his valuable and expert assistance during preparation of the book.

This book was an opportunity to bring the European and U.S. research and breeding networks together, as well as include some authors from the southern latitudes. Most of the chapters have mixed U.S. and European authorship, and the authors have worked with great inspiration, together sharing knowledge and experience. The editors are most grateful to the various author groups, because without their commitment, this book would not have achieved a high level of quality!

We would like to individually thank those who patiently assisted us in the finalization of the book. Laurie McKenzie read and provided feedback on a number of chapters as they came in, and Berend-Jan Dobma assisted with the exacting process of finally formatting and assembly of the chapters.

Finally, we send thanks to our families for their patience and support as we burned the midnight oil in bringing this task to fruition.

Section 1

General Topics Related to Organic Plant Breeding

1

Organic Crop Breeding: Integrating Organic Agricultural Approaches and Traditional and Modern Plant Breeding Methods

Edith T. Lammerts van Bueren and James R. Myers

Introduction

Organic agriculture is continuously growing worldwide on land and farms in more than 160 countries as well as in the global marketplace (Willer and Kilcher, 2011). Globally, there are 37.2 million hectares of organic agricultural land (including in-conversion or transition hectarage), which is about 0.9% of all arable lands. Of the total organic area in 2009, most (24.9%) is in Europe, followed by Latin America (23.0%), Asia (9.6%), North America (7.1%), and Africa (2.8%). Some individual countries (mainly those in Europe) had higher percentages due to support by national policies, e.g., Austria (18.5%), Sweden (12.6%), and Italy (9.0%; Willer and Kilcher, 2011).

Organic agriculture has its origins in the early 1900s with individuals advocating that “living soil” was a fundamental value of sound agriculture (Balfour, 1943; Howard, 1940; Pfeiffer, 1947; Steiner, 1958; Rodale, 1961). It was not until the 1970s that the organic movement grew substantially, however. Growth of the movement coincided with consumers’ and farmers’ reactions against the unsustainable environmental impact of the agriculture of that time. In the 1990s, organic agriculture became large enough to attract the interest of major food suppliers. In 2008--2009 organic products occupied about 5% of the market and were worth 55 billion US dollars, or 40 billion euros (Willer and Kilcher, 2011). To date, increasing development in the organic sector is influenced by three main drivers: Values (see four basic principles of the International Federation for Organic Agricultural Movements in Chapter 7), protest (promoting organic agriculture as an alternative strategy) and market (an economic interesting niche market). Alrøe and Noe, 2008.

Regulations translating the values and principles of the organic sector into rules and standards (IFOAM, 2005; Luttikholt, 2007) have been harmonized to promote global trade. The four basic principles of the organic movements as described by the world umbrella organization IFOAM, include (a) the principle of health: Expressing the concept of wholeness and integrity of living systems and supporting their immunity, resilience, and sustainability; (b) the principle of ecology: Promoting diversity in site-specific ecological production systems; (c) the principle of fairness: Serving equity, respect, justice, and stewardship of the shared world; and (d) the principle of care: Enhancing efficiency and productivity in a precautionary and responsible way (IFOAM, 2005; Luttikholt, 2007).

These principles have been codified in governmental regulations such as the National Organic Program (NOP) in the United States (USDA, 2002) and in Europe by the European Commission (EC, 2007).

It was only in the early 1990s that crop breeding and seed production came to the fore as an issue for organic growers and consumers in response to the emerging field of genetic engineering (GE) and strengthening of intellectual property rights. The organic sector began to discuss ways to actively stimulate crop improvement to meet organic principles.

In this chapter we will describe how organic management differs from conventional agricultural management, what plant traits are required for optimal adaptation to organic farming systems, and ways to acquire such adaptation via cultivar selection, seed production, and breeding. We also summarize the history and future perspectives for organic crop breeding in the United States and Europe.

How Different Are Organic Farming Systems?

When the U.S. National Organic Standards Board convened to advise the USDA on developing organic regulations, they described organic agriculture as:

“… an ecological production management system that promotes and enhances biodiversity, biological cycles, and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain, and enhance ecological harmony” (USDA, 2002).

Organic farming is more than merely replacing chemical pesticides and fertilizers with organic ones. Emanating from the principles of health and ecology, the aim has been to move away from curative measures and to amplify agro-ecological system resilience by developing preventative strategies at the system level (e.g., Kristiansen et al., 2006; see table 1.1). The goal is to stimulate a high level of internal system self-regulation through functional diversity in and above the soil, as opposed to depending on external inputs for regulation (Østergård et al., 2009).

Table 1.1 Overview of the main difference in crop management between conventional agriculture, sustainable low-external input farming systems and organic farming systems

In considering differences among current farming systems in Western societies (e.g., conventional with high-external inputs systems, conventional systems reducing external inputs to become more sustainable, and organic farming systems) organic farming systems are the most extreme of the three types in refraining from chemical-synthetic inputs and in using preventative rather than curative measures. Although conventional low-external input farming seeking sustainability can be considered an intermediate between high-external input farming and organic farming, there is still a critical difference. It aims to reduce the input levels through precision farming methods and integrated pest management but still relies on chemical inputs to quickly correct during crop growth. In contrast, organic farming systems that cannot (easily) “escape” by applying curative methods rely on indirect, long-term strategies of fostering systems resilience. Organic farming systems focus on soil building through increasing organic matter, which increases water holding capacity and buffers against perturbations to the system. Such systems generally lack short-term controls (e.g., by applying mineral fertilizers with ready water-soluble nutrients or pesticides) to modify the growing environment during the season. Because organic farmers have fewer means to mitigate environmental variation, the varieties grown in organic agriculture will exhibit larger genotype by environment interactions, with greater emphasis placed on cultivar traits that allow adaptation to variable growing conditions (Lammerts van Bueren et al., 2007).

Another important difference among the aforementioned farming systems is that the main source of nitrogen (N) in organic farming systems is mineralization of organic matter, making N availability less controllable (Mäder et al., 2002). Under low temperatures in spring, soil microbiota that mineralize organic matter are not active enough to provide sufficient N, causing crop growth to lag and allowing weeds to compete. This requires cultivars that can cope with early season low fertility and produce vigorous growth to cover the soil as early as possible.

Consequences for Cultivar Requirements

A conclusion drawn from the description in the previous section is that conventional agriculture has more external means to adapt the environment to optimal crop growth, whereas organic farming systems need cultivars to adapt to the given environment. Crops bred for conventional production may be adapted to a narrower range of environmental conditions, especially those controlled by the external inputs of the grower. Therefore, cultivar selection is more critical for organic than for conventional farmers. The emphasis is on choosing flexible, robust cultivars that are adapted to such farming systems and that possess yield stability and can compensate for unfavorable conditions.

Organic growers have largely depended on cultivars bred for conventional systems, but not all are optimal for organic farming systems because traits associated with independence from external inputs have not received high priority in current breeding programs.

Traits

A focus on breeding for organic agriculture would require a shift from emphasis on maximizing the yield level in combination with the use of “crop protectants” to an emphasis on optimal yield stability. One of the main characteristics of organic farming is a multilevel approach to increasing system stability to reduce risk of failures. A similar approach could apply to cultivar development to adapt to less controllable and unfavorable growing conditions (see table 1.2). The aim would then not only be adaptation to low nutrient levels supported by improved interaction with beneficial soil mycorrhizae, but also morphological and phytochemical traits that reduce disease susceptibility (wax layers in Brassica species, open plant architecture), enhance weed competition (early vigor and planophile growth habit), and increase in flavonoids and glucosinolates (pest feeding deterrents; Stamp, 2003; Züst et al., 2011).

Table 1.2 Differences in plant ideotype between high input conventional and low-input organic cropping systems

ConventionalOrganicAbove-ground traitsPerforms well at high population densityOptimal performance at lower densitiesIncreased harvest indexIncreased harvest index, but not as dramatic as for conventional productionErect architecture and leaves, shortened plant statureTaller plants, spreading canopy to be productive in low input situationsWeeds controlled by herbicidesWeeds limited by competition (plant height, spreading architecture), plants tolerate cultivationYield is maximized with high level of inputsMaximized sustainable yield achievable with input of nutrients from organic sourcesPest and disease resistance to specific complex of organisms; need for resistance to diseases of monoculture systemsPests and pathogens of monoculture potentially less severe, pathogen and pest complex differ; induced resistance relatively important; secondary plant compounds important for pathogen and pest defenseRhizosphere traitsRoot architecture unknownExploratory root architecture; able to penetrate to lower soil horizonsAdapted to nutrients in readily available formAdapted to nutrients from mineralization – not readily available; need for nutrient use efficiency; responsive to mycorrhizaeLegume-specific traitsNitrogen production by rhizobia of lesser importanceRhizobia more important; discrimination against infective rhizobia important for N acquisitionHarvest and marketing traitsImproved labor efficiencyIncorporate traits that improve working conditionsImproved processing, packing, and shipping efficiencyImproved nutrition, taste, aroma, and textureCrop shaped by mechanical harvest constraintsTraits priorities set jointly by researcher and farmer

From Cultivar Evaluation to Organic Seed Production and Plant Breeding Programs

Just as conventional colleagues do, organic farmers are always looking for the best cultivars to meet their needs. As described above, cultivar choice is a valuable tool of organic farmers to increase system and yield stability. Many research projects have emphasized farmer participatory trials to evaluate current cultivars to select the best performing cultivars under organic growing conditions. The next step in evolution to an organically based breeding program has been to produce organic seed of the most suitable conventionally bred cultivars. The subsequent step has been to identify “ecological” traits that should be included in current breeding programs. Often breeders interested in breeding for low-input or organic farming have also found that the protocols for cultivar testing need to be adapted to allow appropriate cultivars to enter the market (e.g., as in Europe; Löschenberger et al., 2008; Rey et al., 2008; see Chapter 8).

The final step in program evolution has been to develop appropriate cultivars through breeding programs that are conducted under organic conditions. Table 1.3 shows an overview of such steps that currently coexist in the market. These steps represent a continuum that, depending on the goals of the breeding program, may fall somewhere in between. For example, rather than maintaining two distinct programs for conventional and organic, some private companies do their early breeding in conventionally managed environments, then test later generations in both conventional and organic trials (Löschenberger et al., 2008).

Table 1.3 Time schedule to develop organic seed production and plant breeding

TimeActivityProductCurrentSelection of best-performing conventionally bred cultivars; No use of GM cultivarsConventionally bred cultivarsNo chemical post-harvest seed treatmentsConventionally produced, untreated seedsShort-termOrganic seed production of the best suitable conventionally bred cultivarsConventionally bred cultivarsOrganic seed treatmentsOrganic seed productionMid-termIncluding “ecological” plant traits in conventional breeding programsLow-input cultivarsAdapted protocols for organic variety trialing (e.g., VCU) to allow adapted cultivars to pass testing thresholdsOrganic seed productionLong-termWhole breeding cycle under organic conditionsOrganically bred cultivarsIncluding the concept of integrity of plantsOrganic seed production

Organic Seed Production

Crucial to engaging breeding companies to in breeding better adapted cultivars is stimulating organic seed production of the best performing cultivars. Even before organic breeding became an issue, organic seed production (free of pre- and post-harvest chemicals) had already started to develop on a small scale in the 1970s. This was mainly driven by small enterprises concerned about lost genetic diversity that had once preserved older heirloom and regional varieties. With more stringent rules on the use of organic seed incorporated into organic regulations in the United States and the Europe Union, the conventional seed industry became interested in serving this market. As a result, the availability and use of certified organic seed has increased and seed businesses have matured. Both small organic enterprises and larger commercial companies (who have traditionally only serviced conventional markets) are dealing with organic seed production of both horticultural and field crops.

At present, one can generally distinguish four types of organic seed production businesses:

Fully organic and independent seed companies;More or less independent daughter seed companies linked through formal partnerships to conventional seed companies;An integrated part of a conventional seed companies;Conventional seed companies that chooses not to produce organic seed.

Confronted with a limited assortment of suitable cultivars, organic growers have become more aware of the need for greater cultivar choice with a greater diversity in cultivar types (e.g., open-pollinated, F1 hybrids, or variety mixtures). In this context, organic crop breeding has become an emergent sector in business and science.

The History of Organic Crop Breeding in Europe and the United States

Breeding activities for organic agriculture in Europe and the United States have had distinctive historical trajectories that are products of different laws and policies concerning seeds and plant breeding.

Europe

In Europe, plant breeding within the organic sector started in the 1950s on a small scale conducted mostly by biodynamic farmers considering selection as part of their farming system. They felt that it was imperative to allow cultivars to co-evolve over time into more resilient farm organisms (e.g., Kunz and Karutz, 1991). In that context Martin and Georg Schmidt developed (“regenerated”) winter rye through the ear-bed method by sowing the kernels according the position in the ears and developing a procedure for selection resulting in a very tall (2 m) winter rye cultivar named ‘Schmidt Roggen’ (Wistinghausen, 1967). In the 1980s a biodynamic working group of farmer breeders and specialized breeders/researchers met in Dornach, Switzerland, to discuss several research methodologies. In 1985 a group was formed in Germany (“Initiative Kreiz”) that led to the founding of Kultursaat in 1994, which is an association for biodynamic breeding research and maintenance of cultivated species (see www.kultursaat.org; Fleck, 2009). This group now consists of approximately 40 breeders and farmer-breeders, each improving one or more crop species in the context of a biodynamic farm. They currently have registered about 40 new vegetable cultivars. Kultursaat considers breeding to be a public activity and the group is supported financially by donors and seed funds. The seed production of these new cultivars and older open-pollinated and heirloom varieties is organized by the company Bingenheimer Saatgut AG in Germany. In addition to vegetable breeders, several biodynamic cereal breeders began programs in the mid-1980s in Germany and Switzerland (e.g., Kunz and Karutz, 1991; Müller et al., 2000).

Toward the end of the 1990s, broader support emerged to address gaps in improving cultivars for organic farming systems, and breeding research was initiated by organic research institutes and universities in Europe, which were funded on a project basis by national governments and as European cross-country consortia: For example, a large-scale collaborative breeding project SOLIBAM from 2010–2015 for several crops (www.solibam.eu).

To stimulate knowledge exchange on breeding for organic agriculture, a European Consortium for Organic Plant Breeding (ECO-PB) was founded in 2001. Among other functions, it has organized several conferences (see www.eco-pb.org) to provide a venue for information exchange. ECO-PB acts as an umbrella organization that supports harmonization of the national organic seed regimes by organizing roundtable and workshop meetings on the issue (e.g., Lammerts van Bueren and Wilbois, 2008).

Increasing numbers of conventional breeders became interested in breeding for the organic sector. Not only was there a need to serve this growing market, but they also saw it as an investment in breeding for the future, as conventional agriculture moves toward increasing sustainability. During the Eucarpia Conference on Breeding for Organic and Low-input Agriculture in 2007 in Wageningen, the European Association of Plant Breeders and Researchers (Eucarpia) founded the Section “Organic and Low-input Agriculture” (www.eucarpia.org). To support publishing of peer-reviewed results, a special issue of Euphytica was published in 2008 (Lammerts van Bueren et al., 2008). Also the Proceedings of the Second Conference of the Eucarpia Section Organic and Low-input Agriculture revealed many research projects aimed at improved selection methods or strategies for organic plant breeding (Goldringer et al., 2010). In addition to the fact that several European universities have various research programs set up to develop methods to obtain adapted varieties, Wageningen University in the Netherlands initiated an endowed chair specialized in Organic Plant Breeding in 2005. Kassel University in Germany established a full-time chair for Organic Plant Breeding and Biodiversity in 2011.

United States

Origins of organic plant breeding in the United States are not well documented. The emergence of organic organizations came about in the 1970s, and around the same time, seed companies and nonprofit organizations (NGOs) with an interest in seeds arose (Dillon and Hubbard, 2011).

While little is known about the varieties in use by the early practitioners of organic agriculture in the United States, most were almost certainly non-hybrid, open-pollinated (OP) heirloom varieties. The early seed companies were selling predominantly OP varieties to organic growers, and NGOs such as Abundant Life and Seed Saver’s Exchange were focused primarily on preserving heirlooms as a counter to the loss of biodiversity that was beginning in the formal seed sector. The use of OPs and heirlooms was tied to environmental, economic, and social sustainability values and was a reaction against what organic practitioners saw happening in the conventional seed industry. The ability to save OP seed fit well with the “back to the land” movement of the 1970s, which embraced organic agriculture and had a strong belief in self-reliance. With the exception of field corn, where most varieties offered commercially are F1 hybrid, catalogs selling organic seed carry proportionally more OPs than F1 hybrids (Dillon and Hubbard, 2011).

The Organic Food Production Act passed in the 1990 farm bill gave the federal government the authority to craft a national organic standard. This resulted in the publication of the National Organic Program (NOP) in 2000, and after receiving feedback from stakeholders, the program was implemented by USDA in 2002. It was apparent from the beginning that access to certified organic seed was a limitation, as apparent in the NOP advisory on certified organic seed which states “The producer must use organically grown seeds … except … non-organically produced, untreated seeds and planting stock may be used to produce an organic crop when an equivalent organically produced variety is not commercially available” (USDA, 2002). This exception was instituted because certifying agencies and regulators recognized that the organic seed market was not large enough to supply the needs of the organic sector, and that many organic growers relied on conventional sources for their seed needs. Over time, this loophole shrunk. In 2010, certification inspectors were requiring that a grower check at least three seed sources to determine if their desired variety or equivalent was available as certified organic seed. If not, then the grower was allowed to use untreated conventionally grown seed. Much of the recent surge in plant breeding and trialing activities have sought to increase the portfolio of varieties available to growers in organic form.

Organic plant breeding activities by the private sector are not well documented, but probably began in the 1970s or 1980s on the part of companies that were selling organic seed. Organic plant breeding in the public sector was formalized in the mid-1990s with funding from federal grant programs such as the USDA Sustainable Agriculture Research and Education program (SARE), federal Risk Management Agency (RMA), USDA Value Added Producer Grants program (VAPG), and USDA Integrated Organic Program (IOP), which later became the Organic Research and Education Initiative (OREI). NGO organizations funding organic research included the Organic Farming Research Foundation (OFRF) and the Farmers Advocating for Organics fund (FAFO). At least 57 projects were funded through these venues from the mid-1990s to 2010 (Dillon and Hubbard, 2011). Funding has been distributed to both field and vegetable crops with the majority going to wheat and vegetables. Over this time period approximately $9.1 million (€6.3 million) has been invested with most of it administered recently through USDA OREI grants. A large part of these projects has been a farmer participatory component. One of the most difficult aspects of this funding is that it has typically been for a year or a few years at a time, preventing continuity in programs that generally require a decade to develop. It is only recently that varieties from the first programs have been released and the number is expected to grow.

Organization of meetings for information exchange has been relatively recent in the United States. Among the first sponsored by the American Society of Agronomy, Crop Science Society of America, Soil Science Society of America (ASA-CSSA-SSSA) was an Organic Symposium in 2003 (Podoll, 2009). Another Organic Symposium was conducted as part of the 2005 Annual Meeting was about “Organic Seed Production and Breeding for Organic Production Systems.” In 2007, the American Society of Horticultural Sciences Annual Meeting sponsored a colloquium on “Breeding Horticultural Crops for Sustainable and Organic Production.” Regional meetings, such as Organicology in the Pacific Northwest, Ecofarm in California, MOSES in Wisconsin, and the NOFA conferences in the North east have all had plant breeding and seed components.

Comparison of European and U.S. Experiences

One of the obstacles to European organic breeding efforts has been the registration requirement for any variety in commercial trade (see also Chapter 8). The same obstacle has not been present in the United States, where growers have had freer access to older traditional varieties. This has perhaps caused the U.S. breeding effort to lag behind that of Europe because there has not been the regulatory-driven need to breed new varieties. In general, the European organic breeding effort has been ahead of the U.S. effort, when the first breeding efforts took place, in the organization of conferences, and in establishing chairs of organic breeding at public institutions.

Funding for organic breeding is roughly similar on both sides of the Atlantic. Given the limited information available, it is difficult to compare European and U.S. private sector efforts, but European companies have invested more heavily than U.S. companies, and in fact, some of the largest organic seed companies in the U.S. are European based.

Since the late nineteenth century, the U.S. has strongly supported public plant breeding through the land-grant university system. However, in the last two decades, the ranks of public plant breeders have declined. Some of this has come about by reduced federal funding to support these positions, and some have been converted into biotechnology positions. Another source of pressure on public plant breeding has been strengthening the private sector through the advent of stronger intellectual property rights. As private companies have taken over plant breeding efforts in many crops, there has been less of a need for public plant breeders in those crops, with a subsequent increase in the difficulty for public plant breeders to obtain operating funds for their research. One consequence of the loss of public plant breeders has been fewer graduate students trained in plant breeding, which has alarmed private seed companies because they do not see where their future cadre of plant breeders will come from (Ransom et al., 2006).

With the increase in funding for organic research in general, and plant breeding in particular, a niche has been created where public plant breeders can operate. Because private seed companies are reluctant to invest in organic plant breeding, public breeders can conduct research programs on crops that would otherwise be the domain of the private sector for traits of importance to organic production (and ultimately sustainable agriculture). At the same time, these types of projects provide a venue for training the next generation of plant breeders.

Perspectives and Challenges for Breeding for Organic Agriculture

Although organic seed production is increasing annually, specific organic breeding programs are few, and many are focused on cereals.

Currently three types of breeding programs are operating (Wolfe et al., 2008):

a. Conventional breeding programs resulting in cultivars (by chance) also suitable for organic farming systems;

b. Conventional breeding programs aimed at cultivars adapted to low-input and organic agriculture;

c. Organic breeding programs fully conducted under organic growing conditions.

The organic sector is too small to financially support enough programs to improve a wide range of crops, so the reality is that these three types of programs will run in parallel for at least the next two decades (Osman et al., 2007). Another model calls for cooperation of organic breeding programs with conventional breeding companies and institutes that recognize the need for sustainability – and who anticipate developing societal recognition from the contribution that breeding for low-input and organic agriculture can make.

The challenges for research to support the development of breeding for organic farming systems focus on the following three categories:

a. Defining which selection criteria are relevant per crop;

b. Defining selection methods;

c. Developing appropriate socio-economic and legal conditions to stimulate organic breeding programs.

In many regards, organic production is still a black box, in terms of knowing what traits are important for adapting a cultivar to an organic system. We know in general terms what conditions are limiting, but what the optimal plant traits might be is open to investigation. An example would be phosphorus use efficiency, which can be achieved through mychorrizal symbioses or through developing vigorous root systems that are better at exploring the soil. Both approaches have advantages and tradeoffs, and it is not yet possible to know which is better for a particular situation.

There is a need to design more efficient breeding methods for organically adapted crops. Farmer participatory methods have been used in organic plant breeding because when working in a new system, breeders do not always know what traits are important to growers. Farmer participatory methods can work quite well, especially in situations that empower farmers and lead them to take over breeding activities, but they have drawbacks in terms of resources required to visit the sites or bring farmers to a central site. There is also a need for breeding methods that can work around techniques or traits that are considered not compatible with organic principles. Examples include cytoplasmic male sterility derived through somatic hybridization and disease resistances developed with the aid of embryo culture.

The socio-economic, policy, and legal frameworks to facilitate organic production are currently lacking. The increasing use of utility patents to protect crop varieties (in the United States) and methods (both in Europe and the United States) are limiting germplasm exchange and thereby reducing the rate of genetic progress. The variety registration system in Europe has difficulties in coping with the heterogeneous materials developed by organic plant breeders who seek diversity in their varieties.

Conclusion

Organic crop breeding is rising from its infancy, has been maturing as a business, and is becoming a scientific discipline. It is contributing not only to the needs of organic farmers who require cultivars better adapted to their farming systems, but also to the development of sustainable agriculture aiming to reduce external inputs. Organic crop breeding is an essential strategy in arriving at such sustainable farming systems.

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2

Nutrient Management in Organic Farming and Consequences for Direct and Indirect Selection Strategies

Monika Messmer, Isabell Hildermann, Kristian Thorup-Kristensen, and Zed Rengel

Introduction

The world is faced with the need to increase food production to feed a rapidly increasing population. A crucial component in this endeavor is improvement and maintenance of soil fertility. Soil fertility is a measure of the ability of soil to sustain crop growth in the long term, and can be determined by physical, chemical, and biological processes intrinsically linked to soil organic matter content, and quality (Bhupinderpal-Singh and Rengel, 2007; Diacono and Montemurro, 2010). Organic agriculture relies on the use of organic fertilizers – as such, the nutrient cycling provided by the decomposition of organic matter is an essential aspect of food production.

Crop residues are an important source of organic matter that can be returned to soil for nutrient recycling and improving soil physical, chemical, and biological properties. Globally, the total crop residue production is estimated at 3.8 billion Mg Year−1 (74% cereals, 8% legumes, 3% oil crops, 10% sugar crops and 5% tubers; Bhupinderpal-Singh and Rengel, 2007). These residues should be returned to soil, uniformly spread over an entire field to prevent depleting the soil in nutrients and organic carbon (C) (Brennan et al., 2000). The nature of crop residues and their management can significantly affect the amount of nutrients available for subsequent crops and the content and quality of soil organic matter (Bhupinderpal-Singh and Rengel, 2007).

Organic agriculture strives for closed nutrient cycles; therefore, inputs should be limited to the farm level. Nutrient input depends on organic fertilizers like green manure, compost or animal manure for building soil fertility. Thus, crops should be adapted to the slow and irregular release of nutrients that might temporarily be in short supply. Root morphology and the capacity to establish beneficial plant microbial interactions both play an important role in nutrient uptake. This aspect has been widely neglected in most conventional breeding programs but might be of special importance in organic farming. In addition, organic farming systems are more heterogeneous compared to conventional farms with respect to crop rotation, type and quantity of organic fertilizer, weed control, or tillage system. Breeders are therefore confronted with developing cultivars that perform well in very different environments. Not only genotypic effects but also genotype × environment (G×E) interactions need to be considered in order to define the most promising breeding strategies.

Availability of Nutrients in Organic Farming

When we want to breed crop cultivars that are better adapted to organic farming practices than current cultivars bred under the conditions of modern conventional farming, it is important to understand how conditions differ between organic and conventional farming. Nutrient availability is sometimes lower in organic systems as demonstrated by several studies comparing organic and conventional rotations (Marinari et al., 2010; Mäder et al., 2007; Olesen et al., 2009). This is mainly due to reduced nutrient input into organic systems. But at times, nutrient availability is not always lower in organic farming. Nutrient balances on organic farms are difficult to determine, as farmers may introduce substantial amounts of nutrients through the import of feed and bedding materials for animals (Gustafson et al., 2003). In most countries, various nutrient sources accepted for organic farming may include some animal manure obtained directly from conventional farms. Large amounts of nutrients are usually applied for vegetable production.

Nutrient availability is not easy to control in organic farming when using inorganic fertilizers with slow nutrient release, which may be variable and often unknown quality. Organic farmers have to rely on the nutrient sources available on the farm or acceptable nutrient sources available from the market. These sources depend not only on local regulations but also on many other conditions. The economic value of nutrient input to organic farms can be very high, such that farmers have experimented with growing grain legumes to use the seeds as fertilizer, or harvesting and drying legume biomass to be used as green manure (Almeida et al., 2008). Such fertilizers will be very expensive relative to nutrient density, but in some situations organic farmers are willing to pay high prices to obtain available nutrients. Unlike inorganic fertilizers available to conventional farmers, there are few possibilities for modifying the nutrient composition of the fertilizers applied in organic farming. In many situations farmers may inadvertently raise the level of too many other nutrients contained as part of an organic fertilizer when aiming at a certain level of, for example, nitrogen. Such problems may be found in all types of organic farming, but will be most pronounced for high value crops, where farmers are willing to invest substantially to secure sufficient nutrient supply. For example, organic broccoli is seldom grown at low nutrient supply, while organic cereal crops may often be. Soil organic matter content is, on average, higher under organic farming compared to conventional farming, due to higher input of organic fertilizers (Leifeld and Fuhrer, 2010). Thus, nutrient mineralization during the growing season is expected to be higher under organic farming. While, on average, the nutrient availability in organic farming is lower than in conventional farming, the absolute amount of plant available nutrients will differ greatly across organic farms and across crops.

There seem to be two basic differences that ideal organic crop cultivars should be adapted to: