Comparison of in vitro regeneration and transformation efficiency among five vietnamese indica rice cultivars

This study optimized the in vitro regeneration and transformation processes for five popular indica rice cultivars in Vietnam named as BC15, Bac Thom 7 (BT7), Khang Dan 18 (KD18), OM5451, and TBR225. The highest callus induction rates (83–93.67%) were achieved on a medium containing 2.5 mgL-l 2,4-D, supplemented with 500 mg L-l each of L-proline, L-glutamine, and casein. Higher or lower concentrations of 2,4-D resulted in reduced callus induction. Among tested cultivars, BT7 exhibited the highest callus induction rate of 93.67%. Shoot regeneration was optimized on a medium with a combination of 0.5 mg L-l kinetin, 2.0 mg L-l BAP, and 0.5 mg L-l NAA, resulting in regeneration rates ranging from 80.23% to 90.77% across cultivars, with BT7 exhibiting the highest regeneration rate (90.77%). Hygromycin at 20 mg L-l was optimal for selecting transgenic calli, with BT7 showing the highest transformation efficiency opdetermined to be optimal for selecting transgenic calli, with BT7 achieving the highest transformation efficiency (44% hygromycin-resistant callus and 29% GUS expression). PCR analysis confirmed a high proportion (87.5%) of transgenic plants in the BT7 cultivar. These findings indicate that the BT7 is the most suitable cultivar for genetic transformation and gene editing applications.