During the past seventy years, worldwide more than 2250 varieties have been released that have been derived either as direct mutants or from their progenies Induction of mutations with radiation has been the most frequently used method for directly developed mutant varieties The prime strategy in mutation-based breeding has been to upgrade the well-adapted plant varieties by altering one or two major traits, which limit their productivity or enhance their quality value In this paper, the global impact of mutation-derived varieties on food production and quality enhancement is presented In addition, the economic contribution of the selected mutant varieties of rice, barley, cotton, groundnut, pulses, sunflower, rapeseed and Japanese pear is discussed In several mutation-derived varieties, the changed traits have resulted in synergistic effect on increasing the yield and quality of the crop, improving agronomic inputs, crop rotation, and consumer acceptance In contrast to the currently protected plant varieties or germplasm and increasing restrictions on their use, the induced mutants have been freely available for plant breeding Many mutants have made transnational impact on increasing yield and quality of several seed-propagated crops Induced mutations will continue to have an increasing role in creating crop varieties with traits such as modified oil, protein and starch quality, enhanced uptake of specific metals, deeper rooting system, and resistance to drought, diseases and salinity as a major component of the environmentally sustainable agriculture Future research on induced mutations would also be important in the functional genomics of many food crops

Global impact of mutation-derived varieties

Plant tissue culture has become one of the fundamental tools of plant science research. It is extensively employed in the production, conservation and improvement of plant resources. The presence of somaclonal variation in populations derived from tissue culture is affecting the use of tissue culture negatively and has remained a major problem. Conversely, it is a source of new desirable clones/variants with better agronomic traits. In this review, we summarize the possible causes, detection methods and desirability of variants. Somaclonal variation is one of the most researched and reviewed topics. Hence, we restricted ourselves to outlining various examples which may be used as important references for researchers who intend to identify and/or characterize somaclonal variants while using tissue culture for research and production. Emphasis is placed on the negative effects of somaclonal variation. However, this review also includes examples of some useful variants generated as a result of somaclonal variation.

Somaclonal variation in plants: causes and detection methods

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The testing and release of genetically modified organisms (GMOs)—in particular GM plants—is tightly regulated internationally to prevent any negative effects on the environment or human health. However, these regulations are based on transgenic organisms and do not discriminate between transgenic plants and cisgenic plants, although we believe that they are fundamentally different (see sidebarNow, cisgenic plants fall under regulations designed for transgenic organisms, possibly because there have not yet been any applications for the approval of the deliberate release of cisgenic plants into the environment.

Definitions of key terms in relation to plants

Cisgenesis is the genetic modification of a recipient plant with a natural gene from a crossable—sexually compatible—plant. Such a gene includes its introns and is flanked by its native promoter and terminator in the normalsense orientation.Cisgenic plants can harbour one or more cisgenes, but they do not contain any transgenes.

Transgenesis is the genetic modification of a recipient plant with one or more genes from any non‐plant organism, or from a donor plant that is sexually incompatible with the recipient plant. This includes gene sequences of any origin in the anti‐sense orientation, any artificial combination of a coding sequence and a regulatory sequence, such as a promoter from another gene, or a synthetic gene.

Traditional breeding encompasses all plant breeding methods that do not fall under current GMO regulations.As the European legal framework defines GMOs and specifies various breeding techniques that are excluded from the GMO regulations,we use this framework as a starting point, particularly the European Directive 2001/18/EC on the deliberate release of GMOs into the environment (European Parliament, 2001). Excluded from this GMO Directive are longstanding cross breeding, in vitro fertilization, polyploidy induction,mutagenesis and fusion of protoplasts from sexually compatible plants (European Parliament, 2001).

Although transgenesis and cisgenesis both use the same genetic …

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Cisgenic plants are similar to traditionally bred plants: International regulations for genetically modified organisms should be altered to exempt cisgenesis

Clonal populations regenerated from single-leaf cell protoplasts of the potato cultivar `Russet Burbank9 display a high frequency of variation for several horticultural and disease resistance characters. Observations over a period of three tuber generations suggest stable changes in tuber shape, yield, and maturity date, in photo-period requirements for flowering, and in plant morphology. Enhanced resistance to early blight (Alternaria solani) and late blight (Phytophthora infestans) diseases also regularly occurs within regenerated populations. These findings are discussed in the context of possible application to varietal improvement, particularly as they pertain to asexually propagated plants.

https://science.sciencemag.org/content/sci/208/4439/17.full.pdf

Potato protoplasts in crop improvement.

The first step in plant breeding is to identify suitable genotypes containing the desired genes among existing varieties, or to create one if it is not found in nature. In nature, variation occurs mainly as a result of mutations and without it, plant breeding would be impossible. In this context, the major aim in mutation-based breeding is to develop and improve well-adapted plant varieties by modifying one or two major traits to increase their productivity or quality. Both physical and chemical mutagenesis is used in inducing mutations in seeds and other planting materials. Then, selection for agronomic traits is done in the first generation, whereby most mutant lines may be discarded. The agronomic traits are confirmed in the second and third generations through evident phenotypic stability, while other evaluations are carried out in the subsequent generations. Finally, only the mutant lines with desirable traits are selected as a new variety or as a parent line for cross breeding. New varieties...

https://www.tandfonline.com/doi/pdf/10.1080/13102818.2015.1087333

Principle and application of plant mutagenesis in crop improvement: a review

Preface 1. General introduction 2. History of mutation breeding 3. Nature and types of mutation 4. Induction of mutations 5. In vitro techniques for mutation breeding 6. Mutation breeding in seed propagated crops 7. Mutation breeding in vegetatively propagated crops References Index.

Mutation Breeding: Theory and Practical Applications

Application of mutation breeding methods in the improvement of vegetatively propagated crops

List of tables. List of colour plates. List of figures. Preface. 1. General introduction. 2. Mutagenic treatments. Introduction. Chemical mutagens. Physical mutagens. References. 3. Other sources of genetic variation. Introduction. Ploidy mutations. Somaclonal variations. References. 4. Shoot apices: Organization and post-irradiation behaviour. Introduction. Structure and functioning of shoot apices. Behaviour of axillary and adventitious buds. The position of a mutated cell within a plant chimerism. Rearrangements of cell layers. Shoot apices after irradiation. Patterns of radiation-induced morphological/histological damage and recovery. The fate of a mutated apical cell diplontic selection. References. 5. Adventitious bud techniques and other in vivo or in vitro methods of asexual propagation of relevance to mutation breeding. Introduction. In vivo techniques. In vitro techniques. 6. Root and tuber crops. General. Cassava. Garlic and shallots. Jerusalem artichoke. Potato. Sweet potato. Yams and various other (tropical) root and tuber crops. 7. Ornamental crops. General. Tuber and bulb crops. Flowering pot plants. Foliage pot plants. Cut flowers. Garden plants. Woody plants. 8. Woody perennials and forest trees. General. Broad-leaved trees. Coniferous trees. Trees used in sericulture (Morus). 9. Fruit crops. Temperate fruit crops. Tree fruits. Small fruits. Grapevine. Tropical fruit crops. 10. Other crops. Essential oil crops. Fiber crops. Rubber. Hops. Sugarcane. Tea. Grasses. Index of references. Index of plant names.

A. M. van Harten

Papers

Mutation Breeding: Theory and Practical Applications

Application of mutation breeding methods in the improvement of vegetatively propagated crops

Applied Mutation Breeding for Vegetatively Propagated Crops

Application of mutation breeding methods in the improvement of vegetatively propagated crops: An interpretive literature review

Broadening the genetic base of crops : proceedings of the conference : Wageningen, Netherlands 3-7 July 1978