Electron Beam Induced Mutation in Curcuma longa L. Against Bacterial Wilt Disease.

Curcuma longa L. is a medicinal plant that contains bioactive constituents with various pharmacological properties. However, turmeric is vulnerable to the bacterial wilt disease caused by Ralstonia solanacearum, substantially lowering yields and resulting in death. Thus, this study aims to induce mutations of turmeric cv. 'Trang 2' by applying electron beams (8 MeV) and selecting the resulting populations resistant to bacterial wilt disease. Sixty-day-old plantlets cultured in vitro were exposed to 0, 50, 100 and 150 Gy electron beams with a 240 Gy/min dose rate. The experiment was performed at the Thailand Institute of Nuclear Technology. To explore the potential of electron beam sensitivity in the survival and growth rate, unirradiated plantlets were used to normalize the radiation treatments. Plantlet survival was used to calculate the lethal dose (LD), and the number of new shoots was used to estimate the growth reduction (GR) dose through regression analysis. The survival and growth rates of the plantlets decreased as the radiation dose increased. At doses of 100 and 150 Gy, the turmeric plantlets could not produce new shoots. The median lethal dose (LD50) was 58.6 Gy. A 50 % growth reduction dose (GR50) was observed at 45.3 Gy. Symptom severity ranged from 11.7 to 91.7 %, demonstrating significantly lower levels in the EBRTP-2 and EBRTP-4 M1V5 electron-beam-irradiated populations. Furthermore, the disease incidence was 33.3 % in the EBRTP-6 population. Finally, turmeric populations resistant to bacterial wilt (EBRTP-2, EBRTP-4 and EBRTP-6) were isolated after electron-beam-induced mutation at 50 Gy. [ABSTRACT FROM AUTHOR]