Effect of Mutagens on The M₁ Population in Horsegram (Macrotyloma Uniflorum) Under Sub-Temperate Conditions of Himachal Pradesh

Dry and healthy seeds of horsegram varieties HPKC2 and VLG1 were treated with five doses of physical mutagen gamma rays viz., 25Kr, 30Kr, 35Kr, 40Kr and 45Kr and chemical mutagen ethyl methane sulphonate (EMS) having different concentrations of 0.1%, 0.2%, 0.3%, 0.4% and 0.5% each to study the biological damage by both the mutagens and their combinations. All the traits showed reduction with an increase in dose of gamma rays, ethyl methane sulphonate and their combinations in both the treatments. The dose dependent relationship was observed for all the traits. The results showed that gamma rays and their combinations with ethyl methane sulphonate are highly effective for modifying majority of the traits in both the varieties HPKC2 & VLG1. Based on the reduction in plant survival, seedling height, seedling leaf reduction, root length, shoot length and seed sterility. Ethyl methane sulphonate was found 1.74, 2.46, 3.51, 1.30, 2.19 and 15.41 times more efficient than gamma rays whereas on the basis of germination percent gamma rays were found to be 1.17 times more efficient than EMS in HPKC2 and the same trend was also exhibited in the variety VLG1 but the frequency varied. Reduction in mean over control at higher concentrations revealed the highest mutagenic response of the genotype.