Effects of cultivation media on In vitro callus induction and regeneration capabilities of pakaumpuel rice (Oryza sativa L.), thai rice landrace

This study determined the effects of different cultivation media and some factors on in vitro callus induction and shoot regeneration of Pakaumpuel rice (Oryza sativa L.), the Thai rice landrace. Pakaumpuel’s dehusked seeds were surface sterilized by using 20% Sodium hypoclorite for 20 min before washed and cultured on Murashige and Skoog (MS) medium in various concentrations of BAP (6-Benzylaminopurine) (0, 0.1, 0.5 and 1 mg/l) and 2,4-D (2,4-Dichlorophenoxyacetic acid) (0, 1, 2 and 3 mg/l) and cultivated in off-light or dark cycle condition for 15 days. Results showed that MS medium with 2 mg/l 2,4-D where incubated in light condition provided the highest callus induction percentage (80 %). For shoot regeneration, calli were desiccated by using silica gel for 0, 30, 90 and 180 min prior to culture on MS medium with 1 mg/l NAA (1-Naphthaleneacetic acid) and various concentrations of BAP (0, 1, 2, 3 and 4 mg/l) for 30 days. Two-way ANOVA results revealed that desiccation periods did not affect plant regeneration percentage of Pakaumpuel rice. Therefore, MS medium with 1 mg/l NAA and 3 mg/l BAP without desiccation induced the significantly highest regeneration percentage (53.33 %), number of shoot per callus (2.80 shoots), longest shoot (12.16 cm) and the highest number of leaves per shoot (2.40 leaves). This discovery can be applied for micropropagation of other Thai rice landraces.