Studies on Effect of Mutagens on Quantitative Characters in M2 and M3 Generation of Horsegram [Macrotyloma uniflorum (Lam.) Verdc]

Background: Induction of mutation plays an important role in the breeding programme among modern methods of plant breeding. Genetic variability is prerequisite for crop improvement and through induced mutation it was found to be very effective for creating variability in the quantitative and qualitative characters. Hence, the present study was aimed to induce genetic variability within short time. In the present investigation positive as well as negative impact on quantitative traits were recorded. Methods: The experiment material comprised of seeds of horsegram [Macrotyloma uniflorum (Lam.) Verdc] variety Paiyur 2 which was subjected to ethyl methane sulphonate (02, 0.3, 0.4 and 0.5%), gamma radiation (100, 200, 300 and 400 Gy) and combination treatments. The mutations affecting gross morphological changes in growth and yield characters such as plant habit, flowering, pod morphology, maturity and seed yield were scored as quantitative characters. The micro mutations at population level can be easily detected in the form of increased variations for quantitative traits in the segregation of mutagen treated populations. Micro mutations can alter morpho-physiological characters hence they are of a particular interest to the plant breeders. ANOVA test was performed to determine the significant differences and duncan’s multiple range test (p=0.05) to compare the differences among treatment means. Result: Among the twenty-five treatments studied both the mutagens, gamma radiations and Ethyl Methane Sulphonate proved to be very effective to induce variability in quantitative traits in M2 and M3 generations. The results of Duncan’s multiple range test analysis revealed that the treatment of mutagens in combinations induced more positive effects as compared to that of using alone. The combined treatments were found positive for improvement of primary branches per plant, no. of pods per plant, pod length, no. of seeds/pod and seed yield per plant in M2 and M3 generations whereas the treatment of gamma irradiation imparted its significant role for improvement of plant height, days required for 50% flowering, days to maturity and 1000 seed weight in both M2 and M3 generations whereas the treatment with Ethyl Methane Sulphonate is useful for improving no. of pods per plant and no. of seeds/pod in M2 generation alone.

Impact of Ethyl Methane Sulphonate Mutagenesis in Artemisia vulgaris L. under NaCl Stress

The present investigation aimed to obtain salt-tolerant Artemisia vulgaris L. to develop a constant form through in vitro mutagenesis with ethyl methane sulphonate (EMS) as the chemical mutagen. NaCl tolerance was evaluated by the ability of the callus to maintain its growth under different concentrations, ranges from (0 mM to 500 mM). However, NaCl salinity concentration at (500 mM) did not show any development of callus, slight shrinking, and brown discoloration taking place over a week. Thus, all the biochemical and antioxidant assays were limited to (0–400 mM) NaCl. On the other hand, selected calluses were treated with 0.5% EMS for 30, 60, and 90 min and further subcultured on basal media fortified with different concentrations of 0–400 mM NaCl separately. Thus, the callus was treated for 60 min and was found to induce the mutation on the callus. The maximum salt-tolerant callus from 400 mM NaCl was regenerated in MS medium fortified with suitable hormones. Biochemical parameters such as chlorophyll, carotenoids, starch, amino acids, and phenol contents decreased under NaCl stress, whereas sugar and proline increased. Peroxidase (POD) and superoxide dismutase (SOD) activities peaked at 200 mM NaCl, whereas catalase (CAT) was maximum at 100 mM NaCl. Enhanced tolerance of 0.5% the EMS-treated callus, attributed to the increased biochemical and antioxidant activity over the control and NaCl stress. As a result, the mutants were more tolerant of salinity than the control plants.

Enhanced production of extracellular lipase by ethyl methane sulfonate from soil fungal strain in submerged and solid-state fermentation condition

Enhancement in the production of enzyme by utilizing different strains of microbe is one of the main prospects in biotechnology. In the present work, ethyl methane sulfonate (EMF) was selected as the chemical mutagen for inducing mutagenesis in fungi. It is a cheap method to induce random mutation as compared to other methods of recombinant technologies. Strain improvement was done by incubating the fungal spore suspension at variable concentrations of EMS i.e. 4% (v/v) and 10% (v/v) for the time period of 60, 90, and 120 min respectively. The set of control was treated with distilled water only. The fungal colonies were found to be maximum in control plate as compared to the EMF exposed plates. The number of fungal colonies was reduced as we raised the exposure time of EMF. Specific activity and the lipase activity of wild strain and hyperproducer were evaluated under the submerged (SmF) and solid-state fermentation (SSF). The wild strain denoted the 3.2 U/ml/min of enzymatic activity under SmF and 15.87 U/g/min of activity under SSF. In contrast, the best enzymatic activity was represented by S2St1 at 10% of EMS after the time period of 60 min i.e. 11.7 U/ml/min under SmF and 99.35 U/g/min under SSF after the time period of 72 hrs. Statistical analysis by using one-way ANOVA determined that the value of F calculated was lower than the F tabulated. So, there was a significant relation between the EMS percentage and time of exposure among the mutated strains. In conclusion, this soil fungal strain can be utilized to produce lipase enzyme for numerous industrial applications.

Genetic Variability through Induced Mutation

The success of plant breeding is based on the accessibility of genetic variation, information about desired traits with well-organized approach that make it likely to develop existing genetic resources. Food security demands to break the yield barrier through increasing new cultivars which can adapt to wide range of environment. It is especially important to observe the character association for yield along with its components before recognizing novel technique to break the yield barrier. There are numerous methods for improved exploiting of the inherent genetic makeup of crops with heritable variations. It is recommended that recognized parental resources can also be induced to mutate for unmasking novel alleles of genes that organize the traits suitable for the crop varieties of the 21st century world. Chemical mutagens have extensively been applied to make genetic changes in crop plants for breeding investigation as well as genetic studies. Ethyl methane sulphonate (EMS) is the most frequently applied as chemical agents in plants. EMS normally induces GC → AT transitions in the genome causing mutated protein that performed different functions rather than normal. It is exposed that the utilization of EMS is an efficient approach for developing novel gene pool.