Improving French bean yield potential through induced mutagenesis using EMS and SA

IntroductionFrench bean (Phaseolus vulgaris L.) holds global significance as one of the most consumed legumes, with commercial value surpassing that of all other legume crops combined. In India, the consumption of French beans has grown steadily, especially in the North Eastern region, driven by heightened consumer interest in its nutritional benefits. Considering these factors, we initiated an induced mutagenesis program to enhance the genetic diversity of locally grown French bean genotypes, traditionally cultivated for their superior adaptability.MethodsTo achieve this, we initiated an induced mutagenesis program. Seeds from the village seed stock were subjected to treatments with varying doses of ethyl methane sulfonate (EMS) ranging from 0.1% to 0.4% and sodium azide (SA) from 0.1% to 0.4%. The objective was to increase yield potential and enhance genetic diversity.ResultsThe treatment with EMS and SA led to a non-specific, dosage-independent reduction in biophysiological characteristics in French bean mutants. Notably, the 0.4% SA treatment significantly inhibited germination and fertility, causing a decrease in chlorophyll (10.02 mg. g-1 FW) and carotenoid (1.57 mg. g-1 FW) levels. This suggests a disruption in genes associated with chlorophyll and carotenoid synthesis. However, in the M2 generation, the mutagenic treatments substantially improved yield and associated traits. The highest pod yield per plant was recorded at 79.50 gm for the 0.2% EMS treatment. A character association study revealed strong correlations (0.217 to 0.995) between pod yield and other agronomic traits.DiscussionThe results indicate that selecting mutants based on these traits in populations treated with EMS and SA can significantly increase crop yield. The 0.2% SA and 0.2% EMS M2 mutant populations exhibited the highest induced variability, making them ideal for selecting higher-yielding mutant lines for further breeding generations. The increased yields in these mutant lines, derived from a local cultivar, show promise for meeting the growing demand for French bean production through their widespread cultivation

Performance evaluation of induced mutant lines of black gram (Vigna mungo (L.) Hepper)

Article Details: Received: 2020-01-12      |      Accepted: 2020-03-02      |      Available online: 2020-06-30https://doi.org/10.15414/afz.2020.23.02.70-77 Present investigation was carried out to explore the possibility of inducing genetic variability for yield and yield contributing traits in well-adapted variety PU-19 of black gram (Vigna mungo (L.) Hepper) following mutagenesis with methyl methane sulfonate (MMS), sodium azide (SA) and hydrazine hydrate (HZ). A considerable increase in mean values for fertile branches per plant, pods per plant and total plant yield was noticed among the mutant lines in M4 and M5 generations. Estimates of genotypic coefficient of variation, heritability and genetic advance for yield and yield components were also recorded to be higher compared to control. MMS followed by SA and HZ showed highest mutagenic potential for improving total plant yield of black gram var. PU-19. Treatment concentration 0.3% was found to be most effective in generating significant increase in total plant yield of black gram var. PU-19. The increased genetic variability for yield and yield components indicates the ample scope of selection for superior mutants in subsequent generations due to preponderance of additive gene action.Keywords: black gram, mutagenesis, chemical mutagens, genetic variability, yield componentsReferences AHLOOWALIA, B., MALUSZYNSKI, M. and NICHTERLEIN, K.(2004). Global impacts of mutation derived varieties. Euphytica, 135, 187. ANNUAL REPORT (2016–2017). In: Government of India, Ministry of Agriculture and Farmers Welfare, Department of Agriculture, Cooperation and Farmers Welfare, Directorate of Pulses Development, Vindhyachal Bhavan, India. AUTI, S. G. (2012). Induced morphological and quantitative mutants in mungbean. Biorem. Biodiv. Bioavail., 6 (Special Issue), 27-39. BHATIA, C. R. and SWAMINATHAN, M. S. (1962). 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Mechanisms of Genome Maintenance in Plants: Playing It Safe With Breaks and Bumps

Maintenance of genomic integrity is critical for the perpetuation of all forms of life including humans. Living organisms are constantly exposed to stress from internal metabolic processes and external environmental sources causing damage to the DNA, thereby promoting genomic instability. To counter the deleterious effects of genomic instability, organisms have evolved general and specific DNA damage repair (DDR) pathways that act either independently or mutually to repair the DNA damage. The mechanisms by which various DNA repair pathways are activated have been fairly investigated in model organisms including bacteria, fungi, and mammals; however, very little is known regarding how plants sense and repair DNA damage. Plants being sessile are innately exposed to a wide range of DNA-damaging agents both from biotic and abiotic sources such as ultraviolet rays or metabolic by-products. To escape their harmful effects, plants also harbor highly conserved DDR pathways that share several components with the DDR machinery of other organisms. Maintenance of genomic integrity is key for plant survival due to lack of reserve germline as the derivation of the new plant occurs from the meristem. Untowardly, the accumulation of mutations in the meristem will result in a wide range of genetic abnormalities in new plants affecting plant growth development and crop yield. In this review, we will discuss various DNA repair pathways in plants and describe how the deficiency of each repair pathway affects plant growth and development

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

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

<div><p>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.</p></div

Interpopulation proximity matrix based on squared Euclidean distance in the different populations of cv. DPL 62 and cv. Pant L 406.

<p>Interpopulation proximity matrix based on squared Euclidean distance in the different populations of cv. DPL 62 and cv. Pant L 406.</p

Estimates of mean values, genotypic coefficient of variation (GCV %), broad sense heritability (<i>h</i>^<i>2</i><i>bs</i> %) and genetic advance as % of the mean (GA %) for six quantitative traits in the M₂ generation of lentil cultivar Pant L 406.

<p>Estimates of mean values, genotypic coefficient of variation (GCV %), broad sense heritability (<i>h</i>^<i>2</i><i>bs</i> %) and genetic advance as % of the mean (GA %) for six quantitative traits in the M₂ generation of lentil cultivar Pant L 406.</p

Estimates of mean values, genotypic coefficient of variation (GCV %), broad sense heritability (<i>h</i>^<i>2</i><i>bs</i> %) and genetic advance as % of the mean (GA %) for six quantitative traits in the M₃generation of lentil cultivars DPL 62 and Pant L 406.

<p>Estimates of mean values, genotypic coefficient of variation (GCV %), broad sense heritability (<i>h</i>^<i>2</i><i>bs</i> %) and genetic advance as % of the mean (GA %) for six quantitative traits in the M₃generation of lentil cultivars DPL 62 and Pant L 406.</p