Abstract

Seeds of niger (Guizotia abyssinica Cass.) cultivar N-71 were exposed to different doses of gamma rays ranging from 0 -152 Gy and varying concentration of ethyl methanesulphonate ranging from 0 - 104 mM. Variations in the percentage of germination and survival, plant height, number of leaves/plant, leaf length, leaf width, number of primary branches, capitulum size, head size, number of ray florets/capitulum, number of disc florets/capitulum, number of capitula/plant, number of seeds/capitulum, seed yield/plant, 1000 seed weight were recorded in the M₁ and M₂ generations. Plants showed decreased growth with increased dose and concentration of the mutagens. There were dose and concentration related effects of the mutagenic treatments on quantitative traits resulting in reduction in traits such as germination and survival percentages, plant height, leaf length and width, number of primary branches and 1000 seeds weight, but increases in number of capitula/plant, number of seeds/capitulum and seed yield/plant was observed in 52 and 78 mM treated M₂ generated plants. Improved oil content was found in gamma ray treated (38, 114, and 152 Gy) M₂ plants and also in 78 mM EMS treated M₂ plants. Early flowering was found in gamma (76 Gy) treated M₂plants.

Key words: Gamma ray, ethyl methanesulphonate, niger, agronomical trait, M₁generation, M₂ generation.