Investigations of scutellum derived calli, cues from size, effective ionic strength of synthetic media and improved regeneration capacity for indica rice

Abstract

Scutellum derived calli of recalcitrant indica rice variety ASD-16 are subjected to qualitative and quantitative changes using different callus induction media (CIM). The suitable media for generation of regenerating calli by evaluating the increase in size of these calli as a function of time (MeazureTM2.0 software), were recorded (till 25-days post-inoculation). After 10-days post-inoculation significant differences which ranged from 5 mm to 6.5 mm and 30% variation in calliQuery size were recorded for different CIM. Improved regeneration achieved by reducing the time on callusing media to 5-days and 10-days. Also, the insights are provided for the role of cationic and anionic strength, phenomics of somatic embryogenesis, and also browning of the calli for recalcitrant indica rice variety ASD-16. The statistical analysis of size of calli with ionic strength of cations K+, H+, NH4+, Mg2+, Ca2+ and anions PO43−, NO3−, Cl− (statistical analysis tool “The Unscramble X”) shows positive correlation. The loss of scutellum derived calli due to browning was reduced by allowing the mature seed used for generation of calli to be attached to the growing calli. The browning of the calli was monitored in different media for the pattern, and statistical evidences are provided for the important role played by ionic ratios of media constituent namely, NH4+/NO3− and SO42−/PO43− (reported here for the first time). Maximum healthy calli obtained (80%) were on CIM-2 whereas maximal browning (60%) was obtained on CIM-4 after 15-days post-inoculation. Successful regeneration is achieved for recalcitrant indica rice variety ASD-16. Successful generation of scutellum derived calli of recalcitrant indica rice var. ASD-16, optimal ions, ionic ratios during the callus induction and reduce browning, calli growth kinetics, and influence on regeneration.