Induced mutagenesis and In vitro cell selection for resistance against Alternaria blight in Brassica napus L.

The percentage of survival of cell lines of Brassica napus was worked out against the different physical (gamma rays) and chemical (EMS) mutagens. Half of the regenerated calli of var. DGS 1 were subjected to three doses viz., 80 Gy, 120 Gy and 160 Gy of gamma rays. However, the treatment did not show any adverse effect on the growth of calli at any of the above doses, though it significantly affected the regeneration percentage. On the other hand, treatment of calli with 3 per cent of EMS for 90 minutes resulted in 100 per cent lethality, whereas, 30 and 60 minutes duration could produce 20 per cent and 15 per cent surviving calli, respectively. Calli treated with two mutagens, viz. gamma rays and EMS were subjected to different concentrations of culture filtrate of Alternaria brassicicola. Survival of the calli decreased with the increase in the concentration of culture filtrate. Among these, the selective dose of culture filtrate was found to be 10 per cent and the cell survival of calli treated with two mutagens at this dose of culture filtrate varied between 1.88 -5.76 per cent in different treatments. The study resulted in regeneration of A. brassicicola resistant plants from selected and unselected calli.