Improvement of Safflower (Carthamus tinctorius L.) for Salinity Tolerance under in vitro Condition

Abstract

Aim: The primary aim of the present study was to screen the salt tolerant calli and optimization of in-vitro regeneration protocol from selected screen calli.
 Methodology: The cotyledonary leaf explants was sterilized by using 1% Bavistin, 0.1% Mercuric chloride and 70% ethanol followed by washing with distilled water. Sterilized explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentration of NaCl (i.e. 0, 50mM, 100mM, 200mM, 300 mM and 400 mM) to check the salinity tolerance ability of PKV pink genotype. In vitro screening of callus was studied by morphological characters like colour and texture of callus, callus growth percentage, relative water contained, cell survivility and proline content from saline stress and unstress calli to confirm the saline tolerance pressure to regenerate the PKV Pink safflower genotype.
 Results: MS medium supplemented with 150 mM NaCl showed 50% survival of calli, whereas no growth was obtained in high concentration of NaCl. Moreover, biochemical assay like proline estimation was done for its confirmation from different NaCl stress and unstress calli. The proline accumulation found to be highest callus grown on MS media supplemented with 150 mM NaCl as compared to control. Also studied the morphological observation i.e. colour and texture of calli, callus growth percentage, relative water content and cell viability under different NaCl stress to select the saline tolerance pressure to regenerate the tolerance line in PKV Pink. The saline tolerance shoots failed to produce in vitro rooting on the standardized rooting medium. So, the different approach like higher auxin shock and grafting experiment were attempted to overcome the rooting problem. Higher auxin shock experiment failed but grafting approach found satisfactory to overcome the rooting in saline tolerance shoot and for development of saline tolerance line in PKV Pink safflower genotype.
 Conclusion: The development of abiotic stress tolerance plants found the better understanding of physiological and biochemical changes in plants under in vitro stress conditions.