Induced mutagenesis for genetic improvement of Allium genetic resources: a comprehensive review

The genus Allium is one of the largest monocotyledon genera having 1000 designated species with commercial and economic significance. Allium cepa L. (onion) and Allium sativum L. (garlic) are the most imperative edible species of this genus which are cultivated and consumed globally. Despite that, not much systematic and focused research has been carried out in these crops due to constraints like biennial nature, high crossability, cross or sexual incompatibilities/limited sexual reproduction, obligate apomict, large genome size, high heterozygosity, etc. To create genetic variability, induced mutagenesis is the optimum and best alternative for Alliums especially for the development of genetically improved and wider adaptive cultivars under changing climatic scenario. Development of new cultivars having tolerance against various biotic and abiotic stresses needs continuous efforts and attention of the breeder. For that, sufficient and wide genetic variation in the germplasm is the driving force for the breeders to select best genotypes. Development of mutants can be an alternative breeding strategy since mutations cause heritable genetic variations, which provide the eventual foundation for the evolution of new cultivars, forms or species. Such variations could be created artificially through various chemicals or physical agents, known as mutagens. Mutation breeding is an efficient and conventional method of crop improvement. With the aid of modern omics and molecular markers, allium breeding could be accelerated to develop desired products under rapidly climate scenario. This is the first comprehensive and detailed review on induced mutagenesis and mutation breeding in alliums.