Improvement of drought tolerance of patchouli through gamma irradiation and in vitro selection

Abstract

The research was undertaken to obtain drought-tolerant patchouli putative mutant calli through gamma-irradiation and in-vitro selection using Polyethylene Glycol (PEG). Patchoulina 2 variety was used as the mother plant. Embryogenic calli were induced on three medium formulation (combination of 0.1; 0.3 and 0.5 mg/l 2.4D with 0.1 mg/l BAP). The induced embryogenic calli were then exposed to nine levels of Gamma irradiation (0, 5, 10, 15, 20, 25, 30, 35, and 40 Gray) in combination with two levels of PEG (0 and 20%). The results showed that MS media with 2.4-D 0.3 mg/l and BAP 0.1 mg/l was the best medium for callus induction. The ability of calli to survive decreased with increasing doses of gamma irradiation. The radiosensitivity of patchouli calli showed that LD20 at 14.06 Gray and LD50 at 26.98 Gray. The drought-tolerant patchouli putative mutant calli were obtained from gamma-ray irradiation doses 15, 20, and 25 Gray in selection media 20% PEG has better drought stress tolerance compared to parent Patchoulina 2 variety. Further selection in the glasshouse and field are needed to obtain a candidate variety of patchouli drought tolerance.