346. Nielen S., Forster BP, Heslop-Harrison JS. 2018. Mutagen effects in the first generation after seed treatment: biological effects of mutation treatments. Chapter 4 In: FAO/IAEA. Manual on Mutation Breeding – Third edition. Spencer-Lopes MM, Forster BP, Jankuloski L (eds), Food and Agriculture Organization of the United Nations. Rome, Italy. 301 pp. Free download of whole book:
The third edition of the Manual on Mutation Breeding, prepared by the IAEA/FAO (International Atomic Energy Agency/Food and Agriculture Organization of the United Nations) Joint Division in genetics and plant breeding describes advances in plant mutation breeding, in irradiation techniques as well as in the use of chemical mutagenesis, in seed-propagated and vegetatively propagated crops, and in the types of traits that we believe warrant urgent attention to achieve the set target of global and nutritious food security for all. It also provides a comprehensive overview and guidelines for new high-throughput screening methods – both phenotypic and genotypic – that are currently available to enable the detection of rare and valuable mutant traits and reviews techniques for increasing the efficiency of crop mutation breeding. Over 3275 mutant varieties in more than 220 plant species have to-date been officially released worldwide (see http://mvd.iaea.org/). Their value is measured in billions of dollars of additional revenue, in millions of cultivated hectares and – most importantly – in innumerable people leading happy and healthy lives.
Chapter 4 discussed the first mutation population (M1) suffers from physiological disorders as a result of the mutagen treatment. This is a major reason why phenotypic selection for mutation cannot be done in the M1 generation. In addition, most induced mutations are recessive and therefore the mutant phenotype cannot be observed until the mutation is homozygous. Moreover, the mutation induced is originally a one-cell event and is not present in every cell of the plant. Thus, M1 plants must be regarded as chimeric plants. For practical purposes the most important effects are growth retardation, sterility and death of the M1 plants. Physiological disorders may be linked to chromosomal and/or extrachromosomal damage, but a separation of the two causes is usually not possible.
Regardless of these effects, the general weakened state of M1 plants usually means that the M1 population should be grown in benign (stress-free) environments to maximise growth, fertility and the production of the next (M2) generation.
346. Nielen S., Forster BP, Heslop-Harrison JS. 2018. Mutagen effects in the first generation after seed treatment: biological effects of mutation treatments. Chapter 4 In: FAO/IAEA. Manual on Mutation Breeding – Third edition. Spencer-Lopes MM, Forster BP, Jankuloski L (eds), Food and Agriculture Organization of the United Nations. Rome, Italy. 301 pp. Free download of whole book:
Molecular cytogenetics and genome evolution 