Tendency of Salt Tolerance in Siw Gliang and Paya Luem Kaeng Rice Cultivars Derived from Tissue Culture Plantlets

Abstract

This research aimed to investigate the optimal media for callus induction and shoot regeneration in         Siw Gliang and Paya Luem Kaeng rice cultivars. In vitro evaluation for salt tolerance of these rice cultivars were also studied. Rice seeds were surface sterilized and cultured on Murashige and Skoog (MS) medium supplemented with various concentrations of 2,4-D and NAA. The suitable callus induction medium which showed the greatest fresh weight of callus (111.00 mg) in Siw Gliang cultivar was the modified MS medium containing 1 mg/l 2,4-D. In Paya Luem Kaeng rice cultivar, the highest callus fresh weight (148.00 mg) was observed when seeds were cultured on modified MS medium containing 1 mg/l 2,4-D and 1 mg/l NAA. Shoots were regenerated from calli cultured on the modified MS medium supplemented with various concentration of BA, NAA and coconut water. The MS medium supplemented with 2 mg/l BA, 0.5 mg/l NAA and 10% (v/v) coconut water was the suitable medium for shoot regeneration from the calli of Siw Gliang rice cultivar. The average shoot number produced from calli cultured on this medium was 6.0. In Paya Luem Kaeng rice cultivar, 4.8 shoots/callus were successfully regenerated on MS medium supplemented with 1 mg/l BA, 0.5 mg/l NAA and 10% (v/v) coconut water. The plantlets were selected for salt tolerance by culturing on medium supplemented with 0, 0.5, 1.0, 1.5 and 2.0% NaCl. The results showed that the survival percentage of plantlets decreased with increasing NaCl concentrations in both rice cultivars.  The highest concentrations of NaCl that plantlets of Siw Gliang and Paya Luem Kaeng rice cultivars could tolerate were 1 and 1.5%, respectively. Based on these results, it seems like plantlets of Paya Luem Kaeng cultivar are slightly tolerate to in vitro NaCl stress than those of Siw Gliang cultivar.