Screening for sheath blight resistance lines of rice (0ryza sativa L.) variety swarna by using of chemical mutagen

The present investigation was undertaken to identify the resistant lines amongst mutated rice population of the variety swarna induced by the sodium azide. The variability in disease reaction was observed among mutated rice lines. Out of the total 1000 mutant plants, 47 plants were screened that show low disease index, ranged between 0 to 5 were selected for next M generation. In M2 generation the selected genotypes show differences for disease index, only 12 lines shows resistance in M2 generation in field condition and in humidity chamber condition only 8 lines shows resistance. The number of resistance lines were decreases in humidity condition. Non significant variation in morphological expression and in yield attributes among the selected mutants was also reported. Thus, these lines could be considered a potential source for disease resistance against the sheath blight of rice and could be used further in the crossing programme for development of sheath blight resistant rice variety.