Optimization of gamma radiation and sodium azide treatments for induced mutations in ginger (Zingiber officinale Roscoe) tissue culture

Ginger ( Zingiber officinale Roscoe) is a versatile herb commonly used in cooking, food processing, medicine, and as an ingredient in various products. As an economically significant crop, ginger also has substantial export potential. This study aimed to determine the optimal dose of gamma radiation and the ideal concentration and exposure time for sodium azide treatment to induce mutations in ginger tissue culture. Ginger plantlets cultured on MS medium supplemented with 1 mg/L of BAP (6-benzylaminopurine) were subjected to acute gamma irradiation at doses of 0, 10, 20, 30, 40, and 50 Gy (dose rate: 3.37 Gy/min) using the Gamma MARK I Irradiator at the Nuclear Technology Research Center (KU-NTRC), Kasetsart University. The experiment used a completely randomized design (CRD) with three replications. The survival rate and new shoot development of the M 1 V 1 generation were assessed 60 days after irradiation (DAI). At 60 DAI, a significant difference was noted, with irradiated plantlets exhibiting lower survival rates compared to the control group. The survival rate among irradiated plantlets did not differ significantly across the 20–50 Gy range, with survival percentages ranging from 55.2% to 59.4%. As a result, the LD 50 (60) could not be determined. However, an increased radiation dose negatively affected plantlet growth, with the new plantlet development at 60 DAI showing more significant inhibition than the control. Compared to the control, the dose causing a 50% reduction in tissue growth was identified as 16 Gy (GR 50(60) ). Therefore, the optimal gamma radiation dose for inducing mutations in ginger tissue culture is between 10 and 20 Gy. For sodium azide treatment, a factorial experiment in CRD with three replications was conducted, analyzing two factors: sodium azide concentration and exposure time. The results indicated that the most effective sodium azide concentration was 0.1 mM with a treatment duration of 1–2 hours, whereas 0.3 mM was optimal for treatments shorter than 1 hour. The M 1 V 2 generation exhibited phenotypic changes, including variegated and curled leaves and dwarf plant morphology, resulting from the acute gamma irradiation and sodium azide treatments, suggest the potential development of new ornamental or compact ginger varieties.