Rafiul Amin Laskar

Assessment of genetic response and character association for yield and yield components in Lentil (Lens culinaris L.) population developed through chemical mutagenesis

Abstract Genetic variation is imperative to any plant improvement program. Therefore, this study was primarily based on this aspect of inducing desirable genetic variation for enhancement of the available lentil genetic diversity. The lentil seeds were treated with methyl methanesulfonate (MMS) alone and in combination with dimethyl sulfoxide (DMSO) for inducing polygenic variation as well as determining the impact of DMSO on mutagenecity of MMS. Comparative observations were recorded for bio-physiological damages, morphological variation, and quantitative traits to assess the genetic response of the lentil cultivar L 4076 toward the different concentrations of chemicals. Significant statistics suggested that the DMSO interfere with the extent of mutagenecity of MMS in lentil which could be attributed to either synergistic action of both or variation in MMS uptake. The outcome of mutagenesis on the character association study revealed that mutagenic treatments can modify significantly the manner of association between any two traits in lentil. The moderate doses of MMS in combination with 2% DMSO showed notable diminution in the biological damages while accelerating the rate of desirable high-yielding mutants had proved to be economical. The segregate of the selected mutants in future generations will definitely contribute to the improvement of Lentil genotype.

Assessment on induced genetic variability and divergence in the mutagenized lentil populations of microsperma and macrosperma cultivars developed using physical and chemical mutagenesis

Induced mutagenesis was employed to create genetic variation in the lentil cultivars for yield improvement. The assessments were made on genetic variability, character association, and genetic divergence among the twelve mutagenized populations and one parent population of each of the two lentil cultivars, developed by single and combination treatments with gamma rays and hydrazine hydrates. Analysis of variance revealed significant inter-population differences for the observed quantitative phenotypic traits. The sample mean of six treatment populations in each of the cultivar exhibited highly superior quantitative phenotypic traits compared to their parent cultivars. The higher values of heritability and genetic advance with a high genotypic coefficient of variation for most of the yield attributing traits confirmed the possibilities of lentil yield improvement through phenotypic selection. The number of pods and seeds per plant appeared to be priority traits in selection for higher yield due to their strong direct association with yield. The cluster analysis divided the total populations into three divergent groups in each lentil cultivar with parent genotypes in an independent group showing the high efficacy of the mutagens. Considering the highest contribution of yield trait to the genetic divergence among the clustered population, it was confirmed that the mutagenic treatments created a wide heritable variation for the trait in the mutant populations. The selection of high yielding mutants from the mutant populations of DPL 62 (100 Gy) and Pant L 406 (100Gy + 0.1% HZ) in the subsequent generation is expected to give elite lentil cultivars. Also, hybridization between members of the divergent group would produce diverse segregants for crop improvement. Apart from this, the induced mutations at loci controlling economically important traits in the selected high yielding mutants have successfully contributed in diversifying the accessible lentil genetic base and will definitely be of immense value to the future lentil breeding programmes in India.

Induced mutation analysis with biochemical and molecular characterization of high yielding lentil mutant lines

Induced mutagenesis generates macromolecular variations which ultimately alters the bio-physiological and morphological nature of the crop genotypes. In the present study, molecular characterization of six high yielding lentil mutant lines, developed from hydrazine hydrates (HZ) and gamma rays mutagenesis, was carried out with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and random amplified polymorphic DNA (RAPD) markers. Activity of nitrate reductase (NR) and content of chlorophyll and carotenoid were found to be significantly high in the mutant lines. Protein and mineral (Fe, Zn & Cu) contents were also increased considerably in the mutant lines compared to their respective parent genotypes. SDS-PAGE profile of seed storage proteins showed 35 unique bands with 97.14% polymorphism. Genetic divergence analysis generated total 41 reproducible RAPD bands with average calculated polymorphic percentage of 63.06%. Among the primers, OPA-10 showed the highest polymorphism with significant PIC value. Genetic divergent analysis revealed that genome of cultivar DPL 62 mutated relatively more than the cultivar Pant L 406 due to the mutagen treatments, while DPL 62-B and Pant L406-A were the most divergent mutants induced in the present study. Biochemical and molecular profile of the induced mutant lines facilitates a basis for future conservation and utilization strategies to widen the genetic base of the current lentil breeding population.

Effect of gamma radiation and EMS on mutation rate: their effectiveness and efficiency in faba bean (Vicia faba L.)

ABSTRACT Faba bean is one of the most important grain legumes in the world because of its multiple uses and its ability to grow over a wide range of climatic conditions. The objective of this study was to evaluate the effectiveness and efficiency of single and combination doses of gamma rays and ethyl methanesulphonate (EMS) on two different varieties of faba bean. Studies on induced mutagenesis in faba bean involving EMS and gamma rays are sparse. Genetically pure, uniform, dry and dormant seeds of Vicia faba varieties Vikrant and PRT-12 were treated with four different doses of gamma rays (100, 200, 300 and 400 Gy) and of EMS (0.01, 0.02, 0.03 and 0.04%). However, the utility of a mutagenic agent is determined by its ability to induce a high frequency of desirable mutations as compared to undesirable ones; thus, it is necessary to assess the effectiveness and efficacy of mutagens. The results indicated that EMS is more effective in inducing mutations than gamma rays, with the following trend: EMS > gamma rays+EMS > gamma rays. However, with regard to mutagenic efficiency measured based on seedling injury, gamma rays were more efficient than EMS, with the following trend: gamma rays > gamma rays+EMS > EMS. Both mutagenic effectiveness and efficiency were found to be higher at lower doses of both the mutagens. The possible reason for decrease in mutagenic efficiency and effectiveness with increase in dose may be the higher dose of mutagens and less damaging effect of lower doses of mutagens.

Morphological characterization of gamma rays induced multipodding mutant (mp) in lentil cultivar Pant L 406

Abstract Purpose: Lentil (Lens culinaris Medik.), being a self-pollinated crop with narrow genetic base, is an important target crop for mutation breeding experiments. The purpose of the investigation was to create, select and characterize unique mutations in inflorescence traits that have strong impact on lentil yield and yield stability. Materials and methods: Healthy and uniform seeds (moisture 11.0%) of Lens culinaris Medik. cultivar Pant L 406 were irradiated with 100, 200, 300 and 400 Gy of gamma rays. The mutagenized populations were maintained up to mutant generation third (M3) to screen for stable mutations in the inflorescence architecture of the lentil. The selected mutant mp ‘Multipodding’ trait, i.e. multiple pods per peduncle, was morphologically characterized and quantified in subsequent mutant generation fourth (M4). Results: The morphological characterization of the ‘multipodding’ mutant (mp) revealed substantial morphological mutations were induced by the treatment of gamma rays. The estimation of yield per plant (g) between the mutant (mp) and parent cultivar Pant L 406 showed non-significant variation due to significant reduction in seed weight. Conclusions: The novel ‘multipodding’ (mp) mutant induced in the present study can play a key role in understanding the genetic network controlling legume inflorescence architecture and in genomics-assisted breeding for development of elite lentil cultivars.

Effects of dosage and durations of different mutagenic treatment in lentil (Lens culinaris Medik.) cultivars Pant L 406 and DPL 62

In order to broaden the genetic base of lentil, induced chemical mutagenesis was performed. Dry and healthy seeds of lentil cultivars Pant L 406 and DPL 62 were treated with 0.02% MMS (6hrs), 0.04% MMS (6hrs), 0.02% MMS (9hrs) and 0.04% MMS (9hrs) prepared in sodium phosphate buffer at 7.0 pH for 6 hours at room temperature. Bio-physiological observations showed almost a direct relationship with the MMS concentrations and treatment duration, where inhibition and sterility increases with increase in concentration and duration. The 0.02% and 0.04% for 6 hrs treatments of MMS were found effective in inducing sufficient genetic variability in both the cultivars of lentil especially for selection of yield attributing traits, and 0.04% for 9 hrs induced higher desirable phenotypic variations with few unique phenotypes of future interest, whereas 0.04% for 9 hrs found to have highest lethal dose value and % variations in the all variant small survival population. Plant habit and leaf morphology were found most sensitive phenotypic category towards the MMS doses used. Also the character association between yield and other agronomic traits were altered and improved due to the mutagenic treatments. Overall, the results were promising and useful for future crop improvement work on lentil.