Electron beam induced mutation in Curcuma longa L. against bacterial wilt disease

Curcuma longa L. is a major bioactive constituent (curcumin) possessing various pharmacological properties. However, a major problem of turmeric crop production is bacteria wilt disease caused by Ralstonia solanacearum leading to a substantial reduction in yield and plant death. This research aims to induce mutation of turmeric cv. Trang2 by 8 MeV electron beam in vitro culture plantlets and to select the turmeric against bacterial wilt disease. Sixty-day-old in vitro culture plantlets were exposed to 0, 50, 100 and 150 Gy electron beams with a dose rate of 240 Gy/min, at the Thailand Institute of Nuclear Technology (Public Organization), Thailand. To explore the potential of electron beam-sensitivity on survival and growth rate, unirradiated plantlets were used to normalize the radiation treatments. Plantlet survival was recorded to calculate the lethal dose (LD), and the number of new shoots was recorded to estimate the growth reduction dose (GR) through regression analysis. The plantlets survival and growth rate were decreased over the accompanying cultured period together with increased radiation doses. At doses of 100 and 150 Gy, the turmeric plantlets were unable to produce new shoots. The median lethal dose was 58.6 Gy (LD50). A 50% growth reduction dose revealed at 45.3 Gy (GR50). Symptom severity ranged from 11.7% to 91.7%, demonstrating significantly lower levels in EBRTP-2 and EBRTP-4 M1V5 electron beam irradiated populations. Furthermore, the disease incidence was 33.3% in the EBRTP-6 population. This study, 3 irradiated M1V5 populations were isolated EBRTP-2, EBRTP-4 and EBRTP-6 from 50 Gy electron beam irradiation.