Elevating morphology and essential oil in cumin genotypes through polyploidy induction

•Tetraploid cumin shows 30–100 % higher essential oil yield than diploids.•Field study reveals polyploidy challenges beyond controlled environments.•Tetraploid cumin exhibits distinct morphological changes in the field.•Colchicine-genotype interaction guides optimal treatment for morphological traits.•Delayed flowering in tetraploid cumin suggests prolonged vegetative phase. Polyploidy induction is a valuable tool for improving plant breeding outcomes, influencing key plant characteristics. This study investigates the effects of induced polyploidy on various traits in five genotypes of cumin (Cuminum cyminum L.), contributing novel insights to the ongoing research in this domain. Employing varied colchicine concentrations (0.025, 0.05, 0.1, and 0.2 w/v) targeted at the apical meristem, successful chromosome doubling in tetraploid plants (2n = 4x = 28) is achieved, with the optimal induction observed at 0.05 % colchicine. Beyond conventional cytological assessments (chromosome counts, flow cytometry and cytological traits), the investigation extends to elucidate the impact of polyploidy on morphological characteristics and essential oil (EO) content across the cumin genotypic spectrum in the field. Tetraploid plants exhibit a noteworthy enhancement in EO yield (30–100 %) among the five cumin genotypes compared to their diploid counterparts, presenting a promising avenue for practical applications in medicinal plant cultivation. Chemical analysis by GC–MS reveals the role of induced polyploidy in modulating specific essential oil components. Cuminaldehyde, a key constituent, demonstrates heightened levels in tetraploid plants, shedding light on potential commercial implications for the pharmaceutical and spice industries. This study not only contributes to the scientific understanding of polyploidy induction in cumin genotypes but also introduces novel insights into optimization strategies, morphological alterations, and chemical composition.