Estimation of induced variability in M2 generation of fennel (Foeniculum vulgare Mill.)

Abstract

Mutagenesis involving ionizing radiations have been extensively used for development of genetic and breeding resources with novel characteristics. Genetic variability in fennel for agronomically important traits is low. Thus this study was aimed at generating genetic variability in Rajasthan Fennel-125 variety of fennel using the most potent physical mutagen i.e. gamma rays. The seeds were exposed to different doses of gamma rays (150, 175, 200, 225 and 250 Gy). The M1 and subsequent M2 generations were raised in the field. In M2 generation, large numbers of morphological mutants were identified. Observations were recorded in each of selected putative mutants in M2 generation (from seedling to harvesting stage). Many of the selected variants showed comparatively slow growth and variation in chlorophyll content. The chlorophyll variegation involved either whole plant or was restricted to part of leaves. In chlorophyll mutants, the leaf colour ranged from yellow to pure white. Huge variability was also observed with respect to plant height in selected variants. The selected putative mutants showed variation in flowering time, number of primary branches, number of umbels per plant, number of seeds per umbel and days to maturity. Though plant yield in many of the mutants were low in comparison to the parents, the ideotype of the variants were good with respect to plant height and branching pattern. Many of the hitherto indentified mutants exhibited yield superiority over the parent. The identified variants would be further evaluated for their superiority and the breeding nature in M3 & M4 generation to ascertain the nature of mutation.