Induction Of Genetic Variability Research Articles

Effect of X-rays on Seedling Pigment, Biochemical Profile, and Molecular Variability in Astrophytum spp.

Cacti are important in agricultural economies and one of the most popular horticultural plant groups. The genus Astrophytum is one of the most valuable and desirable cacti for growers and collectors around the world. By selecting the appropriate breeding methods to induce variations in combination with modern biotechnology tools for rapid change detection, it is possible to meet the challenges of the modern world in creating new variability in plants. However, there exists a lack of research concerning the impact of ionizing radiation on cacti. The aim of the study was to assess the effects of X-rays at different doses (0 Gy—control, 15, 20, 25, and 50 Gy) on the dynamics of seed germination in vitro, changes in the color of seedlings, biochemical changes in the content of metabolites and changes at the molecular level in Astrophytum spp. ‘Purple’. A significant effect of X-rays on the induction of genetic variation was observed. Remarkably high polymorphism rates were observed, ranging from 59.09% for primer S12 to a full 100.0% for S3 and S8, as determined by the SCoT (Start-Codon-Targeted) marker. In addition, a large variation in the content of plant pigments (anthocyanins, carotenoids, chlorophyll a, and chlorophyll b) was noted. Additionally, discernible alterations in the color of the tested cactus seedlings, assessed by the RHSCC catalog, were attributed to the impact of ionizing radiation. These findings hold promise for the application of radiomutation breeding in acquiring new cactus cultivars.

Induction of genetic variability with gamma radiation and detection of DNA polymorphisms among radiomutants using sequence-related amplified polymorphism markers in Gaillardia pulchella Foug. plants

Induction of genetic variability with gamma radiation and detection of DNA polymorphisms among radiomutants using sequence-related amplified polymorphism markers in Gaillardia pulchella Foug. plants

Induction of Genetic Variability in Cowpea Variety Videza for Extra Earliness and High Seed Yield using Gamma Irradiation Mutagenesis

Background: Cowpea yields are very low in the West African region due to the prevalence of drought periods. This work, therefore, aimed at developing cowpea genotypes that combine early maturity with high seed yield, through gamma irradiation mutagenesis. Methods: A farmer preferred cowpea variety Videza was improved via gamma mutagenesis. A determined lethal dose 50% (LD50) of 240 Gy was used to irradiate 2000 seeds of Videza by applying a Cobalt 60 source. Selected M1 generation plants exhibiting early maturity and high seed yield were advanced to M2 and further to M3 using Videza as parental control. Result: Compared to the control Videza, the number of days to 90% maturity significantly decreased in putative mutants in the M2 (from 71 days in the control to between 50 and 66 days in mutants) and further decreased in the M3 where mutants matured 10-22 days earlier than the control. Significant increment in 100-seed weight per plant occurred in the M3 mutants. In the M3, 100-seed weight increased from 15.28 g in Videza to 21.71 g, the highest in mutants. Twelve putative mutants were identified that combine early maturity with higher seed yield than the control.

Induction of Genetic Variability in Pusa Jwala and Pusa Sadabahar (Capsicum annuum L.) through Mutation via Sodium Azide and Hydroxyl Amine

The present study was carried out to determine the mutagenic effect of Sodium Azide and hydroxyl amine on the morphological features of Pusa Jwala and Pusa Sadabahar (Capsicum annuum L.) in M2 generation. Seed were pre-soaked in distilled water for 6hrs and later treated with different concentration w/v (0.1, 0.15, 0.20, 0.25) of sodium azide and hydroxyl amine mutagens for 6hrs. The experiment was planted Randomized block design, replicated three times. Observation on growth parameters of M2 mutants of Pusa Jwala and Pusa Sadabahar shown significant variation on the plant height, germination, primary secondary branches, length of fruit, test weight of seed, number of fruits per plant, days to first flower mortality and survival. Most of the parameters decreased with increase in concentration of sodium azide. The result of study shown that sodium azide significantly affects plant height, germination and days to first flowering. Sodium Azide is more effective as compared to the Hydroxyl Amine in inducing genetic variability. Keywords: Chilli, Mutant, Sodium Azide, Hydroxyl Amine, Pusa Jwala, Pusa Sadabahar, Variability

Transposable Elements: Major Players in Shaping Genomic and Evolutionary Patterns.

Transposable elements (TEs) are ubiquitous genetic elements, able to jump from one location of the genome to another, in all organisms. For this reason, on the one hand, TEs can induce deleterious mutations, causing dysfunction, disease and even lethality in individuals. On the other hand, TEs can increase genetic variability, making populations better equipped to respond adaptively to environmental change. To counteract the deleterious effects of TEs, organisms have evolved strategies to avoid their activation. However, their mobilization does occur. Usually, TEs are maintained silent through several mechanisms, but they can be reactivated during certain developmental windows. Moreover, TEs can become de-repressed because of drastic changes in the external environment. Here, we describe the ‘double life’ of TEs, being both ‘parasites’ and ‘symbionts’ of the genome. We also argue that the transposition of TEs contributes to two important evolutionary processes: the temporal dynamic of evolution and the induction of genetic variability. Finally, we discuss how the interplay between two TE-dependent phenomena, insertional mutagenesis and epigenetic plasticity, plays a role in the process of evolution.

MORPHOLOGICAL AND GENETIC DIVERSITY ANALYSIS IN CALENDULA (CALENDULA OFFICINALIS L.) INFLUENCED BY MUTAGENIC EFFECT OF COLCHICINE

Calendula officinalis L. (pot marigold) is one of the main aromatic and medicinal plants with many uses in food and medicines. This study was carried out to demonstrate the efficiency of six colchicine concentrations (0.025, 0.05, 0.1, 0.2, 0.4 and 0.8 per cent, w/v) for Calendula improvement and induction of genetic variation. Colchicine treatments had a positive effect on the number of branches/plant, number of inflorescences, fresh and dry weight of inflorescences, inflorescence diameter, total soluble carbohydrates and β-carotene except for plant height, while seed germination and plant height were reduced. Estimation of heritability, genetic advance, genetic variability and selection of superior genotypes will be an important object in crop breeding and genetic improvement programs, and selection of genotypes with higher desirable characters. Heritability was high and ranged from 48.64 to 90.81, respectively (inflorescence diameter and plant height, respectively). Molecular markers based on a RAPD-PCR study elucidate the classification of induced Calendula mutants into two clusters. The coefficient of genetic diversity was estimated at 30%. A combination of morphological and physiological responses with molecular data contained in the various colchicine treatments illustrated the utility of RAPD-PCR as a method for identifying useful mutants and could be used to detect the colchicine effect significantly. Findings recommend the 0.05 per cent colchicine for efficient breeding calendula mutation and genetic improvement.

Studies on induction of genetic variation through seed mutation in cowpea (Vigna unguiculata L. Walp.) by gamma irradiation

The present study was carried out to induce seed mutants in cowpea for getting desired mutants for increased yield, bold seed size. Dry seeds of cowpea varieties were exposed to gamma irradiation from cobalt 60 source at 250 Gy dosages. The non-irradiated parent was used as the control. Identification and selections were carried out at the second generation (M2). The treated and untreated plants were self-fertilized for five generations to observe different morphological characters in M6 generation. Several unique and interesting mutants were isolated in thisinvestigation. Cowpea mutants were screened for useful agronomic traits. These independent mutants have different phenotypes from control. The most distinct mutants included were different pod size, pod shapeshape and coat color of seeds were also observed. The mutants selected from 250 Gy population included plants with increased vegetative growth of plants, increased number of pods, increase in size of pods, curved pods, early maturing plants with broad leaflets, Plants resistant to thrips, black seed colourand bold seed size. The selected mutants were found to possess useful agronomic traits capable of conferring on them selection advantage for increased yield, easy harvesting and insect tolerance.

Induction of Genetic Variability by Colchicine Treatment in Stevia rebaudiana Bertoni.

Induction of Genetic Variability by Colchicine Treatment in Stevia rebaudiana Bertoni.

English

The objective of this study was to evaluate the induction of genetic variability and plant development of palisade grass (Urochloa brizantha L.) M2 mutants in acclimatization to subtropical climate condition. The mutagenic agent methyl methanesulfonate (MMS), at a dosage of 0.5%, was used to induce mutation in 4,000 seeds of the cultivar Marandu. Thirty five plants survived after the induction of MMS mutagen agent. These plants were isolated transplanted in experimental area to advance the generation. Seeds produced by plants were sown in pots allocated in Biosystems Organized Development incubator and subjected to cold stress at 0°C in seedling stage. Surviving seedlings per family were transplanted to field conditions in Southern Brazil. The plant development was evaluated in the M2 generation during the agricultural years of 2012-2013 and 2013-2014. Genetic variability analyzes were carried out with 21 traits, based on the average Euclidean distance and the relative contribution proposed by Singh (1981). Chemical mutation induction with MMS generates genetic variability in palisade grass, enhancing the selection of superior genotypes in subtropical climate conditions. The chemical induction of mutations with the MMS mutagen provided genetic variability in the population of U. brizantha with formation of 18 divergent groups during the research. Key words: Urochloa brizantha L., plant breeding, genetic recombination, forage, multivariate analyses.

English

English

Induction of genetic variability and isolation of mutants in tuberose (Polianthes tuberosa L)

The effect of various mutagenic treatments on vegetative and floral characters of different cultivars of tuberose (Polianthes tuberosa L) was studied and isolation of promising mutants were done. The experimental material comprised of four tuberose varieties viz., Kalyani Single, Kalyani Double, Suvasini and Prajwal, treated with two doses each of gamma rays viz., (0.5 Kr, 1.5 Kr), X-rays (0.6 Kr, 1.2 Kr) and Ethyl Methyl Sulphonate (0.1 per cent, 0.2 per cent) along with the untreated sample (control). Results indicated that the mutagenic treatments at lower doses had significant stimulative effect on some parameters i.e., sprouting percentage, days taken to sprouting, whereas most of the parameters showed a decrease from desired levels i.e., survival rate, leaf length, number of spikes/plant & florets/spike, flowering duration and vase life. Higher doses of all mutagens were detrimental for vegetative and floral characters. Six mutants were also obtained exhibiting variation in plant height (cv. Prajwal treated with EMS (0.2%)), increase in number of petals per floret (cv. Prajwal treated with 1.2 Kr X-rays), fusion of two floret into one (cv. Suvasini and cv. Prajwal treated with EMS (0.2%)), decrease in number of whorl per floret (cv. Suvasini with 1.2 Kr gamma rays treatment) and presence of stamen in double type cultivar (cv. Suvasini with plant treated with 1.2 Kr X-rays).

Study on EMS Induced Micro-mutational Variability in M2 Generation in Pigeon Pea(Cajanus Cajan L.)

Background/Objectives: To assess the effect of Ethyl Methyl Sulphonate (EMS) on induction of genetic variability in pigeonpea genotypes MA 156 and MAL 13. Methods/Statistical Analysis: Healthy, dried, pure line seeds of the crop were pre-soaked in distilled water for 6 hours and treated with 0.01M, 0.015M and 0.02M aqueous solution of EMS in phosphate buffer solution. Treated seeds were thoroughly washed in the running tap water for four hours and sown in rows along with without treated seeds of each variety as control (soaked in distilled water for nine hours). Results/Findings: Secondary branches, number of pods and yield per plant were higher variable at 0.015M concentration whereas 50 per cent plant flowered and matured earlier at lower concentration of mutagen. Genotypic coefficient of variation and phenotypic coefficient of variation were significantly higher for most of the traits studied i.e. Plant height, number of branches per plant, number of pods per plant, seed yield per plant and 100-seed weight. Conclusion/Application: All the mutagenic treatments were effective in inducing genetic variability in both the genotypes.

Using Chemical and Physical Mutagens for Induction of Genetic Variation in the Quantitative and Qualitative Traits of Three Cultivars of Faba beans (Vicia faba L.)

Using Chemical and Physical Mutagens for Induction of Genetic Variation in the Quantitative and Qualitative Traits of Three Cultivars of Faba beans (Vicia faba L.)

Developing stress tolerant plants through in vitro selection—An overview of the recent progress

Biotic and abiotic stresses impose a major threat to agriculture. Therefore, the efforts to develop stress-tolerant plants are of immense importance to increase crop productivity. In recent years, tissue culture based in vitro selection has emerged as a feasible and cost-effective tool for developing stress-tolerant plants. Plants tolerant to both the biotic and the abiotic stresses can be acquired by applying the selecting agents such as NaCl (for salt tolerance), PEG or mannitol (for drought tolerance) and pathogen culture filtrate, phytotoxin or pathogen itself (for disease resistance) in the culture media. Only the explants capable of sustaining such environments survive in the long run and are selected. In vitro selection is based on the induction of genetic variation among cells, tissues and/or organs in cultured and regenerated plants. The selection of somaclonal variations appearing in the regenerated plants may be genetically stable and useful in crop improvement. This review focuses on the progress made towards the development of stress-tolerant lines through tissue culture based in vitro selection. Plants have evolved many biochemical and molecular mechanisms to survive under stress conditions. The mechanisms of ROS (reaction oxygen species) generation and removal in plants under biotic and abiotic stress conditions have also been reviewed.

Optimization of Gamma Radiation Dose for Induction of Genetic Variation in Sugarcane (Saccharum spp) Callus and Regenerated Shoot Cultures

Callus cultures were established in three commercial sugarcane varieties viz., CoJ 64, CoJ 83 and CoJ 86 from spindle explants on MS + 2,4-D (4 mg l−1) + BAP (0.5 mg l−1) medium. Shoots were regenerated from two-month-old calli on MS + BAP (0.5 mg l−1) medium. Callus and callus derived shoots were treated with gamma (γ) radiation at 20, 40, 60 and 80 Gray (Gy). Per cent shoot regeneration from y-irradiated calli in the three varieties ranged from 90 to 93.8 at 20 Gy, 83.3 to 87.5 at 40 Gy, 30 to 36.4 at 60 Gy and 0 at 80 Gy. Upon irradiating shoots, subsequent shoot proliferation in the three varieties ranged from 90.9 to 93.1% at 20 Gy, 82.6 to 84.0% at 40 Gy and 27 to 32.3% at 60 Gy, whereas 80 Gy dose was 100% lethal. Thus, 60 Gy dose of y-radiation was found to be optimum for carrying out mutagenesis of both callus and callus derived shoots. In the field, different irradiated clones of the same variety exhibited huge variability with respect to number of canes, cane girth, cane height and sucrose content.

Induction of genetic variability in oat

Genetic variability in plants can be maximized through techniques of induction to make selection of genotypes with improved adaptation to cultivation conditions possible. For oat, these techniques are important for a sustainable development through plant breeding programs in southern Brazil. The effects of mutagens (one physical: 60Co gamma rays and two chemical agents: ethyl - methanesulfonate and methyl-methanesulfonate) were compared in the segregating M2 and M3 generations derived from artificial hybridization and induced mutation to compare mechanisms of widening the genetic variability of oat. The methodologies increased the genetic variability in the trait vegetative cycle effectively, by either increasing or reducing the number of days from emergence to full heading; both can be applied in oat breeding programs.

Induction of Genetic Variation in Cowpea (Vigna unguiculata L. Walp.) by Gamma Irradiation

Induction of Genetic Variation in Cowpea (Vigna unguiculata L. Walp.) by Gamma Irradiation

Mutagenesis of Embryogenic Cultures of Soybean and Detecting Polymorphisms Using RAPD Markers

Embryogenic suspension cultures of soybean (Glycine max L. cv. Iroquois) were subjected to mutagenesis using varying concentrations (1, 3, 10, and 30 mM) of ethyl methanesulfonate (EMS). Depending on the concentration of EMS used, the mean survival rate of embryogenic cultures decreased from 74 % (1 mM EMS) to 43 % after 30 mM EMS treatment. Random amplified polymorphic DNA (RAPD) analysis was used to determine whether induction of genetic variability in embryogenic cultures in response to the different EMS treatments may result in identification of polymorphic markers. Two of 35 ‘core’ primers tested revealed polymorphisms. One of the primers, OPO-01/1150, revealed polymorphism in tissue treated with 10 mM EMS, while the other primer, OPO-05/1200, revealed polymorphism in tissue treated with either 1 or 30 mM EMS. These results suggest that RAPD markers are useful in detecting mutations in embryogenic cultures of soybean.

Comportamento de somaclones de arroz derivados de híbridos da geração F1 para resistência à brusone

A indução de variabilidade genética em relação à resistência à brusone, utilizando cultura de tecidos como material, constitui uma das alternativas para a obtenção de novas fontes de genes de resistência. O objetivo deste estudo foi aumentar a freqüência de variantes usando como explante panículas imaturas da geração F1 de cruzamentos envolvendo fontes altamente suscetíveis e moderadamente resistentes à brusone como parentais. Somaclones de arroz derivados de plantas F1 dos cruzamentos Bluebelle/Araguaia e Maratelli/Basmati-370 foram avaliados, nas gerações avançadas, quanto à resistência à brusone e a algumas características agronômicas. Nos testes de inoculações em casa de vegetação, todos os somaclones, de ambos os cruzamentos, na geração R4, apresentaram alto grau de resistência aos patótipos IB-1 e IB-9. Alguns dos somaclones mantiveram-se resistentes na geração R5, em avaliações realizadas com alta pressão de brusone. No campo, os somaclones R5 e R6 mostraram alta freqüência de variação quanto à resistência à doença, altura da planta, produtividade, peso e tipo de grãos. Dois somaclones derivados do cruzamento Bluebelle/Araguaia e 31 somaclones derivados do cruzamento Maratelli/Basmati-370 foram identificados como novas fontes de resistência à brusone, e podem ser utilizados no programa de melhoramento de arroz irrigado.

In vitro induction of genetic variability in cotton (Gossypium spp.)

Through the in vitro culture of excised embryos and ovules, interspecific hybrids have been obtained from cultivated and wild species of Gossypium. The hybrids matured upon transfer to the field. The anthers, ovules and embryos from both the diploid (2n=26) and tetraploid (2n=52) species underwent proliferation, and this response was genotypic. The diploid species invariably showed profuse callusing in comparison with the tetraploid. The callus showed various chromosome numbers, ranging from haploids to hexaploids, and from high polyploidy to aneuploidy. Hybrid callus culture may augment the genetic variability by providing a means for obtaining genetic exchange in interspecific hybrids. The implications of the in vitro induction of genetic variability for cotton improvement are discussed.