Theoretical and practical options for mutation breeding in oil palm are discussed. In theory, haploids are considered the ideal targets, as the induced mutation can be fixed instantly on conversion to doubled haploids. However, haploid/doubled haploid technology is in its infancy in oil palm and therefore other practical targets need to be considered. The two obvious targets are pollen and seed, as these are produced in large numbers in breeding and commercial seed production. Schemes for pollen and seed irradiation and subsequent mutant population development are compared. The irradiation of germinated seed is currently considered to be the better approach in terms of convenience and time. A major constraint in mutation breeding in oil palm is the long life cycle. Oil palm has a long juvenile stage, and it takes 4-5 years from sowing a seed to getting seed of the next generation. Traditionally, mutant selection has relied on phenotypic selection, which can only take place in the second mutant generation (M2) due to the presence of physiological disorders and chimeras in the M1. However, now that the oil palm genome has been sequenced, it is feasible to select for mutants genotypically in the M1. Early detection of mutants is extremely valuable in oil palm, as it saves space in growing up only selected mutants in the field. Mutation breeding is a non-GM technique that has been used for over nine decades. New methods in genetic manipulation include gene editing, which has huge potential for the future but is currently still under debate as to whether it is considered a GM method and is subject to restrictive regulations.

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Physical mutagens, particularly gamma and X-rays, are well established in plant mutation breeding. Although gamma irradiation has been predominant, it involves the use of radioactive isotopes and requires specialist facilities (gamma cells, gamma houses and gamma fields). X-ray machines are more abundant and easier to use, and so are becoming more popular as they do not involve radioactive isotopes and therefore are not governed by the same stringent regulations as gamma emitters. A brief description and comparison of gamma and X-ray irradiation is given. Physical irradiation services are available at the international, regional and national levels. Other non-physical mutagens are discussed in relation to plant breeding and functional genomics.

A practical step-by-step protocol is presented for mutation induction and mutation detection in oil palm. Germinated seed is chosen as the target material for mutation induction, as this provides the quickest development of mutant populations (as discussed in Chapters 3 and 4 of this manual). The protocol adopts gamma irradiation as this is a proven effective mutagen for mutation breeding. Genotyping is deployed in the M1 to select for mutants in target genes. These selections, plus a random selection of M1 plants, are then advanced from nursery to field conditions to produce mature palms, which may be self-pollinated to produce the M2 generation. The M2 generation is subject to phenotypic screening at all stages in plant development, from seed, germination, seedling, juvenile to adult palms. A list of target genes and traits for mutation is given. As discussed in Chapter 4 of this manual, there are two practical targets for mutation induction in oil palm: pollen and seed. The seed option is the more favoured, as it takes less time and involves only one pollination/seed production stage, thus saving time and labour. A step-by-step guide is provided in generating the M1 and M2 populations for mutant detection.