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Participatory plant breeding
Dhan Pal Singh , ... Arti Singh , in Plant Breeding and Cultivar Development, 2021
Abstract
Participatory plant breeding (PPB) was proposed in early 1980s as a socio-technological solution to variety development, such that it is complementary to conventional plant breeding. The main participatory research in plant breeding domain is called PPB or client oriented plant breeding (COPB), and participatory varietal selection (PVS). In participatory research, clients (mainly farmers, but other stakeholders too) are intricately included in all major decisions at all stages of a plant breeding program. The difference between PPB and PVS is the demarcation when client participation starts; specifically, clients are engaged from the first stage of breeding pipeline in PPB, while in PVS farmers are involved in the testing of lines developed by plant breeders.
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Breeding Genetics and Biotechnology
P.D.S. Caligari , J. Brown , in Encyclopedia of Applied Plant Sciences (Second Edition), 2017
Abstract
Plant breeding is an activity that has been carried out since humans first started undertaking settled farming, but its scientific basis was only firmly established with the rediscovery of Mendel's work on genetics at the end of the nineteenth century. The impetus and sophistication of plant breeding have advanced at a tremendous pace over the last 30 years with the implementation of the new biotechnological possibilities. However, plant breeding itself is still necessarily based on sound genetics, experimental design, and traditional evaluation of phenotypes. The strategies therefore underlying the practice of plant breeding are therefore not only relevant but necessary in order to carry out a successful plant breeding program. The basis for such plant breeding practices is set out in this article.
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Mass Selection and the Basic Plant Breeding Algorithm
Thomas J. Orton Ph.D. , in Horticultural Plant Breeding, 2020
Introduction
Plant breeding is defined as human actions that result in the permanent desirable genetic change of a population of plants. The journey by this book from theoretical and historical underpinnings through the actual processes now known as plant breeding thus begins. Mass selection is the simplest form of plant breeding. This primitive method was among the range of basic activities practiced in agriculture by early humans. Since the mid-19th century CE plant breeding had advanced and expanded to become more progressively more specialized and science-based. Following the consideration of the biological facets of plant breeding this textbook will present the various methods ( Section 2; Chapters 13–19 13 14 15 16 17 18 19 ) according to the mating system and appropriate circumstances.
Mass selection is covered in Section 1 ("Elements and Underpinnings of Plant Breeding") as a prelude to the basic plant breeding algorithm and domestication. This will create a framework for subsequent, more complex strategies that will be covered in Section 2. The reader is referred to many other informative and enlightening textbooks to appreciate that the subject of plant breeding may be approached and treated in many different ways (Allard, 1999; Fehr, 1987; Poehlman and Sleper, 2013; Kuckuck et al., 1991; Borojevic, 1990; Chahal and Gosal, 2002; Acquaah, 2012; Fleury and Whitford, 2014; Singh, 2006; Brown et al., 2014).
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Agriculture in the Era of Climate Change: Consequences and Effects
Rahul Bhadouria , ... Pardeep Singh , in Climate Change and Agricultural Ecosystems, 2019
1.10.3 Plant Breeding
Plant breeding techniques are extremely successful and have been widely used in agriculture to enhance the yield of several crop plants over the past five decades ( Jaggard et al., 2010). In addition, under changing environmental conditions plant breeding is even more desirable for the development of crop varieties resistant to multiple environmental stresses (Ceccarelli et al., 2010). Important attributes of plant varieties (cultivars) that should be considered for development through plant breeding under changing environmental conditions include resistance against drought, high temperature, salinity, flooding, and insect pest infestation (Ceccarelli et al., 2010). Thus, plants with the aforementioned characteristics can be raised through the application of classical as well as advanced molecular biology and genetic engineering principles (Cairns, 2013).
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Breeding of Plants
Donald N. Duvick , in Encyclopedia of Biodiversity, 2007
III. Conclusions
Plant breeding—the development of plant varieties—simultaneously exploits and enhances biological diversity.
Plant breeding exploits biodiversity. Modern plant breeding could not exist, could not succed, without recourse to a continuing supply of biologically diverse populations at the variety, species, and family level, and now (thanks to biotechnology) at any level in the world of nature.
Plant breeding enhances biodiversity. Plant breeders of all kinds—full-time professionals, farmer-breeders, and dedicated amateurs—add to the stock of genetically diverse organisms by continually producing new and genetically diverse plant varieties with new, ecologically diverse adaptations. Such increased biodiversity is minuscule when compared with that existing in relatively pristine natural ecosystems, but it is essential for bountiful and dependable production of farm crops.
Plant breeding has caused problems when breeders and farmers ignore or misunderstand the ways in which biodiversity contributes to ecological balance and crop productivity. Excessive dependence on simple solutions such as (for example) single-gene disease resistance has led to problems.
Plant breeding has given greatest benefit when its products and their users took advantage of the beneficial interactions that occur among diverse organisms at each level of complexity from gene to landscape. Much remains to be learned about ways to make the greatest use of biodiversity at each level (e.g., spatial, temporal, and reserve), about how one kind can substitute for another, and when it is best not to substitute. Plant breeding epitomizes the duality of humanity's interaction with biodiversity. We wish to alter and enhance it for the benefit of human needs and wants but we must also avoid altering or depleting it in ways that destroy its benefits to us and to the world of nature—our home.
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Quantitative Genetics and Plant Breeding
John W. Dudley , in Advances in Agronomy, 1997
A PLANT BREEDING
Plant breeding started with primitive people saving seed to plant in succeeding years. In the process, most of our major crops, such as maize ( Zea mays L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and many others, were domesticated. Although there is a tendency to equate the beginnings of plant breeding with the rediscovery of Mendel's laws, major plant breeding discoveries were made prior to 1900. For example, mass selection for sucrose concentration in the beet root began in 1786 and was continued until 1830. The first beet sugar factory was erected in 1802 (Smith, 1987). Thus, planned, directed plant breeding efforts resulted in a cultivar that allowed development of a new industry 100 years before the rediscovery of Mendel's laws. The basic principles underlying maize breeding, i.e., that inbreeding reduces vigor, cross-breeding increases vigor, hybrids could be produced by detasseling one parent, and that hybridization needed to be done each generation if vigor was to be maintained, were known prior to 1900 (Zirkle, 1952)
With the rediscovery of Mendel's laws, genetic principles began to be applied to plant breeding. Smith (1966) traces the developments from 1901 to 1965, including developments in statistical theory that had important implications for plant breeders. The development of hybrid corn and the principles leading to it have been reviewed extensively (Crabb, 1947; Hayes, 1963; Wallace and Brown, 1956) and will not be reviewed in detail here.
Because most of the traits of economic importance are under quantitative genetic control, quantitative genetics became an important contributor to plant breeding theory.
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CROP IMPROVEMENT | Plant Breeding, Practice
P.D.S. Caligari , J. Brown , in Encyclopedia of Applied Plant Sciences, 2003
Introduction
Plant breeding has been practiced since humans first began to cultivate crops. Over the past 100 years the intensity of plant breeding has increased, and is now recognized as an intricate integration of science (or sciences) and practicality. Over recent times the increasing need to feed the world's population, as well as an ever-greater demand for a balanced and healthy diet, has meant that there has been a continuing pressure to produce improved new crop cultivars. The strategies used to produce these are increasingly based on our knowledge of relevant science, particularly genetics, but involves a multidisciplinary understanding that optimizes the approaches taken.
A first requirement of any breeding program is to produce genetic variation in the characters that are to be improved. Once genetic variation is produced, it is necessary to select the desired types, which have a better expression of particular characters or combination of characters. Once identified the selected types need to be stabilized and propagated/multiplied for commercial use.
Plant breeding therefore appears to be a relatively simple process, and in many ways it is true that ideas of crop improvement are simple. However, the reality is more complex. It is possible to consider the three elements of the plant breeding processes (noted above as: to produce genetic variation, to select, and to stabilize and multiply for commercial use) in order to understand modern plant breeding. With this standpoint it is possible to realize what is being done and what alternative techniques might play a role in future cultivar development. However, each of these elements is tailored to be appropriate to the particular type of crop, or species, being improved.
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Participatory Breeding
Eva Weltzien , Anja Christinck , in Agricultural Systems (Second Edition), 2017
Definitions and Terminology
Participatory plant breeding (PPB) includes various approaches of close farmer–researcher collaboration to bring about plant genetic improvement within a species. The basic idea is that farmers and researchers have different knowledge and practical skills, as well as divergent approaches to problem diagnosis and solving ( Weltzien et al., 2003). The strengths and weaknesses of both groups tend to be complementary, so that better research results can be achieved through cooperation (Hoffmann et al., 2007).
All the different phases or stages of a plant breeding program are concerned, and options for farmer participation exist for all of them: setting objectives, creating variability, selecting experimental varieties and testing them, as well as producing and diffusing seed of new varieties (Fig. 8.1).
Figure 8.1. Stages of a plant breeding program.
From Christinck, A., Dhamotharan, M., Weltzien, E., 2005a. Characterizing the production system and its anticipated changes with farmers. In: Christinck, A., Weltzien, E., Hoffmann, V. (Eds.), Setting Breeding Objectives and Developing Seed Systems with Farmers. Margraf Verlag, Weikersheim, Germany, and CTA, Wageningen, The Netherlands, pp. 41–62, p. 11.Collaboration between farmers and scientists can take many forms, and roles and responsibilities can be shared in many diverse ways. Some researchers have tried to classify PPB approaches according to the form of collaboration or the locus of decision-making (Farnworth and Jiggins, 2003; Lilja and Ashby, 1999). In any PPB program, farmers contribute knowledge and information to the joint program, and in some cases also genetic material. For example, farmers can contribute their own check or control varieties to trials, or farmer varieties can also be used as breeding parents in crossing programs. In addition, farmers may be directly involved in the breeding process by conducting and managing trials on their own land, and making selection decisions in various ways. Thus, in addition to knowledge and genetic material, other major contributions of farmers in PPB programs are labor and practical skills regarding the evaluation and selection of test entries.
As with any developing field of research, the terminology for PPB has not been fully standardized, and is used differently by different groups of researchers. Some of the more commonly used terms are explained in the following paragraphs to assist the reader with interpretation of the growing PPB literature.
As in this chapter, PPB is used as an overarching term that includes all approaches to plant breeding, with close collaboration between farmers and researchers (Weltzien et al., 2003). However, some authors focus on the stage of the breeding program in which the collaboration takes place, and on the status of the germplasm under consideration. In this context, one of the most commonly used terms is participatory variety selection (PVS). It is used to describe farmer participation in the process of evaluating finished, stable varieties. Accordingly, the term participatory plant breeding (PPB) is then used only when the project involves farmers' contributions in the earlier phase of variety development; i.e., making crosses or selections in the early (segregating) generations. It is thus important to verify in which way the term PPB is being used in specific publications. Publications that use PPB in a "narrow" way tend to use farmer participatory crop improvement or collaborative plant breeding as overarching terms, which include then both PVS and PPB (Cleveland and Soleri, 2002; Witcombe et al., 1996). These terms are, however, used only rarely.
The term decentralized plant breeding puts emphasis on the importance of selection in the target environment, i.e., farmers' fields, based on considerations regarding the interaction between plant genotypes and the environment. This approach may, however, also imply farmer participation in the selection and diffusion of varieties (Ceccarelli et al., 1996, 2000). Lastly, the term client-oriented plant breeding (COB) has been proposed with the aim to avoid an artificial dichotomy between "participatory" and "nonparticipatory" breeding approaches (Witcombe et al., 2005). The essential strength of participatory methods is seen here in improving the client-orientation of formal breeding programs, with productivity gains and research efficiency as the main goals.
In recent years, involvement of other stakeholders (besides farmers) has gained importance in PPB projects, particularly when biodiversity conservation and breeding activities are tied to value chain development. Such projects tend to involve a variety of actors along food supply chains, and use multistakeholder approaches to achieve their goals. Stakeholders can include, e.g., traders, food processors, restaurant chefs, and urban consumers (Padulosi et al., 2014; Jäger et al., in prep.). In view of this rather confusing terminology, we use PPB in its most generalized meaning throughout this chapter, with a focus on describing the broad range of goals pursued by PPB programs, and the various ways for achieving them.
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Crop Systems
L. Skøt , N.F. Grinberg , in Encyclopedia of Applied Plant Sciences (Second Edition), 2017
Abstract
Plant breeding is concerned with genetic improvement of crops. Phenotypic selection has been and still is the basis for the phenomenal progress that plant breeding has made. The use of molecular marker–assisted selection has been limited until now, but genomic selection (GS) is likely to change this dramatically due to the availability of next generation genomic technology, which facilitates dense coverage of a genome with molecular markers. GS uses all the markers on the genome to estimate their effect simultaneously on a trait using a breeding population of plants with phenotypic and molecular marker data. The estimated marker effects are then used to estimate the genomic breeding values in a test population with only genotypic data available. The aim is to save time by increasing the speed with which breeding cycles can be completed with less need for phenotyping. The major factors affecting the accuracy of these genomic predictions as well as the most commonly used models for generating them will be discussed.
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Integrated views in plant breeding: from the perspective of biotechnology
Grazia M. Borrelli , ... Luigi Cattivelli , in Crop Physiology (Second Edition), 2015
9 Concluding remarks
Plant breeding is a continuous accumulation of superior alleles in the gene pool of the cultivated elite lines and recent developments in biotechnology offer new tools for screening and selecting new alleles. Allele mining allows searching for natural existing alleles in a germplasm collection, while new breeding techniques (similar to traditional mutagenesis) or GM breeding allow generating new alleles for traits of interest. Once the alleles of interest have been identified, high-throughput molecular markers can be used to assemble the most favorable combinations in new varieties and to predict their performance. As a result of this progress in genomics, the breeding process is generally moving from phenotypic selection to an integration between phenotypic selection and genotypic data generated with molecular markers either at a few loci (MAS) or at virtually all the loci of interest in the genome (GS). The relevance of the molecular selection in plant breeding is largely dependent on the species of interest, on the trait under selection and on the cost/benefit ratio. In some species, there is no sufficient molecular knowledge to start MAS, some traits can be easily scored and there is no convenience to develop markers for them, other traits are still too complex to be tackled with molecular markers, for some species– trait combinations the molecular selection is too expensive compared to results. Nevertheless, despite all these limitations, the general trend over the last 10 years and all expectations for the future are toward an increasing role for MAS, GS, GM and other new breeding technologies in plant breeding.
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