Gamma Radiation Effects on some Growth Patterns in Hedge Lucerne (Desmanthus virgatus L.)

Seeds of Hedge lucerne (Desmanthus virgatus) were exposed to different doses (50 to 500 Gys, with an interval of 50 Gys) of gamma rays (Cobalt-60) to determine the effectiveness of different doses on growth behaviour and biomass characteristics. The lethal dose (LD₅₀) was found to be 250 Gys. About thirty five mutants were identified. High biomass yielding dwarf statured plants were identified from the treatments of 350 and 500 Gys irradiation. Similarly high fodder yielding superior plants as a result of increased number of branches ranging from 22–34 were observed in 400 and 450 Gys population when compared to the control (12–16 branches). Plants of bushy stature with shorter intenodal length (2.25 cm) when compared to control (3.75 cm) were found among the 450 Gys population. Prostrate types were also identified among the 50, 350, 400 and 500 Gys population suited for grazing pastures. Based on single plant performance, plants which record high biomass will be identified and M₁ seeds will be collected and studied in further generations.