Enhancement of regeneration potential and variability by gamma-irradiationin cultured cells of Scilla indica

Induced mutagenesis in callus tissues was studied in the medicinal plant Sc illa indica irradiated with different doses of gamma -radiation ranging fro m 2.5 to 20 Gy. Low doses accelerated the cell division and growth rate of the tissues whereas high doses repressed growth rate and resulted in lethal ity of tissues. Various cytological and chromosomal abnormalities were obse rved in the irradiated calli, the degree of which depended upon the dosage. Low doses of irradiation also promoted the regenerating capacity of the ca lli tissues and plants regenerating from them exhibited better growth and v igour compared to normal plants. High doses led to loss of regenerating cap acity and promoted formation of malformed and stunted plants. Cytological s tudy of regenerants revealed both diploid and mixoploid plants but no tetra ploids were obtained.