Effects of Cultivation Media on In vitro Callus Induction and Regeneration Capabilities of Pakaumpuel Rice (Oryza sativa L.), Thai Rice Landrace

Abstract

Current 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 20% Sodium hypoclorite for 20 mins before washed and cultured on Murashige and Skoog (MS) medium in various concentrations of BAP (0, 0.1, 0.5 and 1 mg/l) and 2,4-D (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 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 minutes prior to culture on MS medium with 1 mg/l NAA and various concentrations of BAP (0, 1, 2, 3 and 4 mg/l) for 30 days. The results revealed that desiccation periods had no effect on regeneration percentage and number of shoot per callus, but had effects on shoot length and number of leaves per shoot. Therefore, MS medium with 1 mg/l NAA and 3 mg/l BAP induced the highest regeneration percentage (53.33 %) and number of shoot per callus (4.40 shoots), while the longest shoot (12.82 cm) and the highest number of leaves per shoot (3.00 leaves) were found on the culture on this medium after desiccation for 90 minutes. This discovery can be applied for micropropagation of other Thai rice landraces.