Selection for Drought Tolerance in Rice (Oryza sativa L.) Using Polyethylene Glycol

Abstract

In vitro selection of rice for drought tolerance was conducted. Embryo derived calli of aromatic rice (Oryza sativa L.) variety Khao Dawk Mali 105 were cultured on filter paper bridges soaked in liquid MS medium containing polyethylene glycol 6000 (PEG) at the concentrations of 0, 10, 20, 30 and 40%, respectively. It was found that calli cultured on the medium containing 10% PEG gave higher rate of survival (70.1%) than calli cultured on medium without PEG (67.9%). Rate of survival decreased when the calli were cultured on the medium containing PEG at the concentrations higher than 10%. All calli died completely when cultured on the medium containing 40% PEG. The concentration of PEG which reduced the survival rate of calli to 50% (LDF50) was 29.5%. The surviving calii were selected and cultured on regenerating medium. The results showed that calli survived on the medium without PEg could regenerate into plants at the ferquency of 5.7%. The total number of plants regenerated was 49 plants. Calli survived on the medium containing 10% PEG gave low frequency of plant regeneration (1.3%) and only 2 plants wee produced. Plant regeneration from calli survived on medium containing PEg at the concentraion higher than 10% was seeds were harvested and will be grown as R2 progenies. The progenies will be tested for drought tolerance under greenhouse or field condition.