Phenotypic variations in M2 generation by ethyl methanesulfonate mutagenesis in lucerne (Medicago sativa L.)

Abstract

Context Mutagenesis is an effective method to create genetic variation in an available accession. Aim This study aimed to generate variability in a genetically distinct genotype of lucerne (Medicago sativa L.) by using a chemical mutagen. Methods Eight different ethyl methanesulfonate (EMS) concentrations were used to determine lethal dose for 50% of the population (LD50). Among them, two EMS concentrations were used to treat 20 000 seeds of BAL-08-01 accession. A total of 8301 individual plants from 1225 families in the second generation (M2) were established under field conditions. Phenotypic observations were recorded as per Distinctness, Uniformity and Stability (DUS) testing guidelines. Key results Wide variations were observed for all phenotypic characters. Among these, green fodder yield, plant height and number of tillers varied with a range of 1–372.5 g, 8.1–120.8 cm and 0–77 per plant, respectively. Variations were also recorded for other characters such as leaf shape, flower colour, primary branching, etc. A total of 86.76% of plants showed purple colour flowers. Principal component analysis was performed for fodder characters from each EMS concentration. First, two principal components contributed an overall 97.06% variability. M2 plants outside 95% ellipses show the highest phenotypic variations. Conclusion EMS is effective in inducing mutation in lucerne. Phenotypic mutations were recognised in the M2 generation for the quantitative and qualitative characters and green fodder yield. Implications The resulting high level of variability will serve as source material for the improvement of lucerne for various traits.