Gene Action for yield attributing characters in segregating generation (M₂) of Sorghum (Sorghum bicolor L.)

Gamma rays was used as a physical mutagen to create variability and to study the gene action through mutation in Grain sorghum variety CO(S) 28. The LD ₅₀ for germination was observed as 35 kR and the treatment doses viz., 25 kR, 35 kR and 45 kR were fixed for creating variability. The M₁ generation of all the three treatment doses was raised and selfed plants were forwarded as M₂ generation. Approximately 1500 M₂ plants were raised in each treatment for recording observations. The frequency distribution for the yield and yield attributing traits viz., panicle length, number of primary branches per panicle, number of grains per panicle, 100 grain weight and grain yield per plant were obtained. The Skewness and Kurtosis estimate were calculated to study the gene action. The traits viz., number of grains per panicle and grain yield per plant recorded positive Skewness value in all the three irradiated doses. This indicates the presence of complementary epistatic gene action for these traits and if selection will be made intensively in the segregating generations the gain will be faster and mild selection resulted in slower gain.