Mutagenesis and In vitro selection in Brassica napus L. for resistance against Alternaria blight

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