Induced mutation breeding: a comprehensive review of genetic enhancement and trait-related findings in gladiolus

Gladiolus (Gladiolus grandiflorus L.) is a commercially important cut flower crop, prized for its striking and colourful floral spikes. The increasing global demand for gladiolus underscores the need for genetic improvement, particularly in developing novel flower colours. This review provides a comprehensive overview of the mutation spectra and trait-specific outcomes achieved through various mutagenesis techniques, including physical methods (gamma rays, X-rays and fast neutrons), chemical methods (ethyl methanesulfonate, colchicine and sodium azide) and in vitro methods in gladiolus. Key findings documented across the literature include the development of novel flower colours, enhanced vegetative growth, enhanced vase life and increased tolerance to biotic and abiotic stresses. This review comparatively analyses mutagens and categorises gamma ray doses into low dose, moderate dose and high dose ranges based on lethality, blindness and optimal treatment ranges that maximize beneficial trait expression while minimizing deleterious effects. Various studies have shown that high doses of gamma rays (>7 kR or 70 Gy) cause lethality and low mutation frequencies in gladiolus varieties. Challenges related to mutant stability and chimera formation are also discussed with the aim of facilitating targeted, trait-specific breeding. This comprehensive review is intended to serve as a reliable reference for researchers, breeders and students engaged in mutation breeding for the genetic improvement of Gladiolus.