Abstract

                                Selection by tissue culture through an osmoticum agent polyethylene glycol is precise for drought assessment compared to actual field condition. Mature seeds of fourteen parental lines (four lines and ten testers) and forty hybrids were used for developing callus on Murashige and Skoog (MS) medium supplemented with two treatments viz., MS + 2, 4 –D 2 mg/l and MS + 2, 4-D 2 mg/l + CH 1 mg/l. One hundred mg of embryogenic callus was exposed to basal medium supplemented with different concentrations viz., 0, 0.5, 1, 1.5 and 2 per cent of polyethylene glycol (PEG) - 6000 as chemical drought inducer. Callus induction duration, effect of PEG on callus mass, proline content and plantlet regeneration were studied. Callus volume decreased and total proline content was found to be increased significantly with increased in PEG concentration. In five parents and twelve hybrids, plantlets regeneration was observed up to the highest concentration of PEG. On over all comparison, three parents namely, BR 2655, MAS 26, Vandana and three hybrids namely, TNAU CMS 2A x MAS 26, IR 58025 A x BR 2655, and IR 68897 A x MAS 26 exhibited positive response for all the four characters acting as drought governing indices.

Key words : Rice, PEG, Drought tolerance, Callus growth, Proline content, Plant regeneration