Determination of lethal dose (LD50) and sensitivity of fenugreek (Trigonella foenum-graecum) to sodium azide for induction of mutation

The present experiment was conducted in the year 2021 at Sri Karan Narendra Agriculture University, Jobner, Rajasthan, to determine the optimum dose (LD50) and duration of the chemical mutagen treatment for the induction of desirable mutation. A set of 100 pre-soaked fenugreek seeds were treated with 12 different concentrations of sodium azide, viz. 0.3 mM, 0.6 mM, 1 mM, 2 mM, 3 mM, 4 mM, 5 mM, 6 mM, 7 mM, 8 mM, 9 mM and 10 mM for three different durations, viz. 3 h, 6 h and 9 h. Results showed that a dose-dependent decreasing tendency was observed in germination percentage, survival percentage, root length and shoot length with increasing concentration and duration of sodium azide treatment. Almost all the mutagenic treatments resulted in decrease in germination percentage, survival percentage and seedling height (root and shoot length) with increasing concentrations and duration of mutagen in laboratory conditions. Also, the LD50 value was observed as an 8 mM sodium azide concentration for 6 h in fenugreek. The mutagen treatments given at 9 h duration were detrimental for fenugreek. They cannot be used for mutation induction as they are utterly lethal after a 3 mM sodium azide concentration. So, lower treatments of mutagens have influenced less biological damage and would be suitable for inducing desirable mutations.