Mutagen sensitivity and mutability in lentil

Seeds of two cultivars, each of ‘macrosperma’ and ‘microsperma’ varietal groups of lentil were mutagenised with gamma-rays and NMU to determine their mutagen sensitivity and mutability. The increasing doeses of gamma-rays and NMU decreased germination, root and shoot length, pollen fertility and plant survival, but increased the occurrence of leaf spots. The root system was found to be more sensitive to both mutagens than the shoot. The ‘macrosperma’ varietal group was more sensitive to both the mutagens than ‘microsperma’ group. In ‘microsperma’ group, variety ‘Pusa-1’ was more sensitive to both the mutagens than ‘L-259’, while in the ‘macrosperma’ group ‘L-1491’ showed more sensitivity to the mutagens than ‘L-1492’. Radio-sensitivity corresponded positively with chemosensitivity in both varietal groups. There was a positive relationship between radio- and chemo-sensitivity of the genotypes and their mutability. The results also revealed the existence of a parallelism between radiomutability and chemo-mutability. Due to saturation in the mutational events and vigour of both diplontic and haplontic selection in the biological material, the mutation frequency either decreased or remained constant at higher doses of the mutagens.