Development of autotetraploid garlic (Allium sativum L.) through in-vitro chromosome doubling

Abstract

Genetic variation is closely linked to crop improvement. Since garlic is primarily propagated vegetatively, it exhibits low genetic diversity. In this study, in-vitro colchicine treatment was used to induce polyploidy, aiming to enhance allelic variation. Shoot proliferation was optimized using different concentrations of BAP and TDZ, with 3 mg/L BAP and 0.25 mg/L TDZ showing the highest regeneration. Calli aged 21 days were subcultured and exposed to colchicine at varying levels. The results indicated that 0.05 mg/L colchicine promoted the highest survival, while higher concentrations (0.75 mg) reduced duplication due to toxicity. The LC₅₀ for colchicine was determined to be between 0.03–0.05 mg/L. The induced autotetraploids showed potential for enhanced genetic diversity in garlic. This study highlights the optimal colchicine dose for ploidy induction with minimal mortality, offering a pathway to genetic improvement in vegetatively propagated crops like garlic.