Ethyl Methanesulphonate Mutagenesis Research Articles

Determination of optimal lethal dose for ethyl methane sulphonate (EMS) induced mutagenesis in castor (Ricinus communis L)

Castor, an indeterminate and perennial non-edible oilseed crop is unsuitable for mechanization over a large scale. Chemical mutagenesis using ethyl methane sulphonate (EMS) is resorted to exploit point mutations and induce monospike or synchronous maturity. In the present study, EMS mutagenesis dosage was standardized using combinations of concentration (0.5 %, 1 % and 1.5%) and duration (4, 8, 12 hours) of EMS treatment along with duration of pre-soaking with water (12 and 24 hours). Data on speed and percent germination of the seed along with root and shoot length at 7 days and 14 days after treatment indicated that 12 hours presoaking followed by 8 hours or 12 hours of treatment with 1.0% EMS treatment is the optimum lethal dose for EMS mutagenesis.

A LuALS Mutation with High Sulfonylurea Herbicide Resistance in Linum usitatissimum L.

The cultivation of herbicide-resistant crops is an effective tool for weed management in agriculture. Weed control in flax (Linum usitatissimum L.) remains challenging due to the lack of available herbicide-resistant cultivars. In this study, a mutant resistant to acetolactate synthase (ALS)-inhibiting herbicides was obtained by ethyl methanesulphonate (EMS) mutagenesis using an elite cultivar, Longya10. Whole-plant dose-response assays revealed that, compared to Longya10, the mutant was 11.57-fold more resistant to tribenuron-methyl (TBM) and slightly resistant to imazethapyr (resistance index (mutant/Longya10) < 3). In vitro acetolactate synthase assays showed that the relative resistance of the mutant was 12.63 times more than that of Longya10. A biochemical analysis indicated that there was a Pro197Ser (relative to the Arabidopsis thaliana ALS sequence) substitution within the LuALS1, conferring high resistance to sulfonylurea herbicides in the mutant. Additionally, two cleaved amplified polymorphic sequence (CAPS) markers, BsaI-LuALS1 and EcoO109I-LuALS1, were developed based on the mutation site for marker assistant selection in breeding. Moreover, the mutant did not cause losses in natural field conditions. We find a mutant with ALS-inhibiting herbicide resistance chemically induced by EMS mutagenesis, providing a valuable germplasm for breeding herbicide-resistant flax varieties.

The Analysis of Morphological Diversity and Polyphenols Content of Celosia cristata in M2 Population Induced by Ethyl Methane Sulphonate

Celosia cristata, an edible ornamental plant, is a potential floricultural commodity that needs further improvement to increase its agro-morphological characters and polyphenol content. Induced mutagenesis using ethyl methane sulphonate (EMS) is an effective tool to increase genetic diversity that has been applied in many plant species. This study aimed to assess the morphological diversity, polyphenol content, and antioxidant activities of C. cristata mutagenized by EMS in the M2 generation. A total of 230 M2 plants generated from the M1 generation were evaluated in this study and the polyphenols content and antioxidant activities analysis were conducted on fifteen selected M2 plants. Polyphenols content was analyzed using the Folin-Ciocalteu method and colorimetric method with slight modification, and the antioxidant activities investigated using 2,2’-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and ferric reducing antioxidant power (FRAP) assay with minor changes. There are six subpopulations with the highest diversity of quantitative characters in the M2 population in quantitative characters, i.e. C2-17-1.0%, C2-1-0.7%, C2-20-2.0%, C2-25-0.7%, C2-1-0.9%, and C2-1-0.7%. Changes in the shape and color of leaves, stems, and flowers of C. cristata were also observed in the M2 population. C2.1, C2.6, and C2.12. 2.1, C2.6, and C2.12 are potential plants derived from EMS mutagenesis with the highest polyphenol content and antioxidant capacity in the M2 population. In conclusion, induced mutation using EMS can enhance the agro-morphological diversity, polyphenols content along with the antioxidant activities of C. cristata, and demonstrate the successful mutation breeding program.

Protocol for ethyl methanesulphonate (EMS) mutagenesis application in rice.

Background: Non-transgenic chemical mutagen application, particularly ethyl methanesulfonate (EMS), is an important tool to create mutations and gain a new genetic makeup for plants. It is useful to obtain a sufficient number of mutant plants instead of working with a severe mutation in a few plants. EMS dose and exposure period have been previously studied in several crops; however, EMS used to create point mutations in presoaked rice seeds has not been sufficiently studied and there is no standard protocol for such treatment. The aim of this study is to establish a standard protocol for EMS mutagenesis application in rice. Methods: Two studies were conducted to evaluate the effect of four durations of rice seed presoaking (0, 6, 12, and 24 hours), four EMS concentration doses (0.0%, 0.5%, 1.0%, and 2.0%), and four EMS exposure periods (6, 12, 24, and 48 hours). Germination rate, plumula and radicle length, seedling survival,LD 50(Lethal Dose) determination, shoot length, root length and fresh seedling weight were evaluated. Results: Results showed that a 12-hour presoaking duration, 0.5% EMS dose, and six hours of EMS exposure were the best practices for the optimum number of mutant plants. Conclusions: In light of both this study and the literature, a standard application protocol was established. This application protocol, detailed in this article, contains the following guidelines: (1) Presoaking: 12 hours, (2) EMS application: 0.5% dose EMS and six hours, (3) Final washing: six hours, (4) Drying: 72 hours at 38°C. A user-friendly protocol has been presented for utilization by researchers.

CHEMICALLY INDUCED MUTAGENESIS IN THE KING OYSTER MUSHROOM Pleurotus eryngii TO GENERATE HIGH-TEMPERATURE TOLERANT STRAIN

In this study, a high-temperature-tolerant strain of the king oyster mushroom (Pleurotus eryngii) was generated by chemical mutagenesis. Cultivation of P. eryngii generally involves incubating the mycelia at 25°C and then moving the spawns for further incubation at 18°C for fruitification. However, in tropical countries, the temperature is a major concern in the production of oyster mushroom where the average temperature is 32°C. In the current study, the mycelia were treated with ethyl methane sulphonate (EMS) or methyl methane sulphonate (MMS) for chemical-induced mutation. Seven mutants (EMS 1, 2, 6, 26, 35, 36, and 38) from EMS mutagenesis exhibited higher growth rates than the wild-type strain at 32°C. However, mutant strains from MMS mutagenesis showed a low growth rate when compared with wild-type. On sawdust substrate, the spawn running conditions for these strains were performed at 32°C, and fruitification occurred at 18°C. The yield and biological efficiency of EMS 36 and 38 mutants were higher than those of the wild-type strain. The activities of cellulase and xylanase of EMS 36 and 38 mutants showed that both these mutants had higher activities than the wild-type strain which may influence mushroom production. Therefore, these EMS 36 and 38 mutants can be cultivated in tropical countries, which could provide a high yield and reduce the cost during spawn running step.

Protocol for ethyl methanesulphonate (EMS) mutagenesis application in rice

Background: Non-transgenic chemical mutagen application, particularly ethyl methanesulfonate (EMS), is an important tool to create mutations and gain a new genetic makeup for plants. It is useful to obtain a sufficient number of mutant plants instead of working with a severe mutation in a few plants. EMS dose and exposure period have been previously studied in several crops; however, EMS used to create point mutations in presoaked rice seeds has not been sufficiently studied and there is no standard protocol for such treatment. The aim of this study is to establish a standard protocol for EMS mutagenesis application in rice. Methods: Two studies were conducted to evaluate the effect of four durations of rice seed presoaking (0, 6, 12, and 24 hours), four EMS concentration doses (0.0%, 0.5%, 1.0%, and 2.0%), and four EMS exposure periods (6, 12, 24, and 48 hours). Germination rate, plumula and radicle length, seedling survival, LD50 (Lethal Dose) determination, shoot length, root length and fresh seedling weight were evaluated. Results: Results showed that a 12-hour presoaking duration, 0.5% EMS dose, and six hours of EMS exposure were the best practices for the optimum number of mutant plants. Conclusions: In light of both this study and the literature, a standard application protocol was established. This application protocol, detailed in this article, contains the following guidelines: (1) Presoaking: 12 hours, (2) EMS application: 0.5% dose EMS and six hours, (3) Final washing: six hours, (4) Drying: 72 hours at 38°C. A user-friendly protocol has been presented for utilization by researchers.

Development of Wheat (Triticum aestivum L.) Populations for Drought Tolerance and Improved Biomass Allocation Through Ethyl Methanesulphonate Mutagenesis

The narrow genetic variation for drought adaptive traits and biomass allocation in wheat (Triticum aestivum L.) presents a major bottleneck for breeding. Induced mutagenesis creates genetic variation and complements conventional breeding for drought tolerance improvement. The aims of this study were to induce mutations in wheat genotype LM43 using three ethyl methanesulphonate (EMS) treatments, and to develop mutant populations for improving drought tolerance, biomass allocation and agronomic performance. Experiments were conducted under controlled and field conditions at the University of KwaZulu-Natal. Data on percentage germination (%G), days to 90% maturity (DTM), plant height (PH), shoot biomass (SB), root biomass (RB), root-shoot ratio (RSR), spike length (SL), spikelet count (SPS), thousand seed weight (TSW), and grain yield (GY) were collected from M1 to M4 generations. Significant (p &amp;lt; 0.001) differences among individuals and generations were observed for all the assessed traits and the generation × population interaction effects were significant (p &amp;lt; 0.01) for SB, TSW, and GY due to EMS treatments. The differences among the generations showed that the mutagenic effects were cumulative and exhibited clear segregations in subsequent generations. The new selections with unique biomass allocation, drought response and agronomic performance will be useful for wheat improvement programs.

Protocol for ethyl methanesulphonate (EMS) mutagenesis application in rice

Background: Non-transgenic chemical mutagen application, particularly ethyl methanesulfonate (EMS), is an important tool to create mutations and gain a new genetic makeup for plants. It is useful to obtain a sufficient number of mutant plants instead of working with a severe mutation in a few plants. EMS dose and exposure period have been previously studied in several crops; however, EMS used to create point mutations in presoaked rice seeds has not been sufficiently studied and there is no standard protocol for such treatment. The aim of this study is to establish a standard protocol for EMS mutagenesis application in rice. Methods: Two studies were conducted to evaluate the effect of four durations of rice seed presoaking (0, 6, 12, and 24 hours), four EMS concentration doses (0.0%, 0.5%, 1.0%, and 2.0%), and four EMS exposure periods (6, 12, 24, and 48 hours). Germination rate, plumula and radicle length, seedling survival, shoot length, root length and fresh seedling weight were evaluated. Results: Results showed that a 12-hour presoaking duration, 0.5% EMS dose, and six hours of EMS exposure were the best practices for the optimum number of mutant plants. Conclusions: In light of both this study and the literature, a standard application protocol was established. This application protocol, detailed in this article, contains the following guidelines: (1) Presoaking: 12 hours, (2) EMS application: 0.5% dose EMS and six hours, (3) Final washing: six hours, (4) Drying: 72 hours at 38°C. A user-friendly protocol has been presented for utilization by researchers.

Protocol for ethyl methanesulphonate (EMS) mutagenesis application in rice

Protocol for ethyl methanesulphonate (EMS) mutagenesis application in rice

Morphological variations of wheat (Triticum aestivum L. em. Thell.) under variable ethyl methanesulphonate mutagenesis

Genetic gains in wheat yield have stagnated over the years due to genetic drift. There is a need to create new genetic variation for yield using various methods including ethyl methanesulphonate (EMS). The use of EMS mutagenesis is limited by variations in lethality, efficiency and effectiveness, which confound to selection. The objective of this study was to evaluate morphological variation in wheat after EMS mutagenesis. Wheat genotype LM43 was subjected to EMS mutagenesis under the following conditions: 0.1% v/v for 1 h at 25 °C, 0.1% v/v for 1 h at 30 °C and 0.7% v/v for 1.5 h at 25 °C. Some mutant plants in M1 had significantly (p < 0.05) higher spikelets per spike and kernels per spike. The number of tillers and kernels per spike increased significantly at M2 generation. EMS treatment with 0.1% v/v for 1 h at 30 °C was the most effective and efficient with the lowest biological damage. Macro-mutations were observed in spike, peduncle, awn and flag leaf morphology. The study identified early generation mutants that could be exploited for improving drought tolerance, yield and biomass, or for genetic analysis to identify quantitative trait loci in wheat.

Identification of a cold tolerant mutant in seashore paspalum (Paspalum vaginatum)

Seashore paspalum (Paspalum vaginatum Swartz) is a commonly used warm-season turfgrass with superior salt tolerance. Low temperature is one of the major abiotic stresses limiting its growth and plantation regions. A protocol for ethyl methane sulphonate (EMS) induced mutations from embryogenic callus and selection of seashore paspalum mutant line with enhanced cold tolerance was established in the study. Treatment of embryogenic callus with 5 h of 0.8% EMS resulted in an approximate 50% survival rate of callus, which was used for inducing mutations from embryogenic callus of seashore paspalum. One mutant line (A6) with enhanced cold tolerance was selected and identified from about 10,000 regenerated plantlets. A6 had lower TEL50 (the temperature resulted in 50% electrolyte leakage) and higher survival rate than its wild type (WT) plants after 7 days of cold acclimation. Antioxidant defense system was responsive to low temperature in both genotypes, while higher CAT activity was maintained in A6 than in WT after 3 days of cold treatment. Among four DREB1/CBF genes induced by cold treatment, higher levels of DREB1A, DREB1D, DREB1E transcripts were observed in A6 than in WT. Free amino acids concentrations in response to cold treatment also showed difference between A6 and WT. The results suggest that the response of DREB1/CBFs expression, CAT activity, and free amino acids concentrations to cold is differentially altered in A6 compared with WT, which is associated with the enhanced cold tolerance in A6. A mutant line with enhanced cold tolerance was selected by EMS mutagenesis in seashore paspalum. It had higher catalase activity and DREB1/CBFs transcripts with altered free amino acids than WT.

Seed oil content and fatty acid composition response to ethyl methanesulphonate mutagenesis in vernonia

Vernonia [Centrapalus pauciflorus (Willd.) H.Rob.] is a novel industrial oilseed crop that can be used to produce vernolic acid, a naturally epoxidised fatty acid. The study objective was to determine whether ethyl methylsulphonate (EMS) mutagenesis significantly altered seed oil content and fatty acid compositions in selected vernonia accessions. Seeds were harvested from mutant plants with and without visual chlorophyll mutations from the Vge-1 and Vge-4 vernonia accessions, subjected to seed oil content and fatty acid composition analyses and compared with untreated controls. Visual chlorophyll mutations confirmed EMS mutation in harvested plants. Ethyl methylsulphonate mutagenesis significantly reduced vernolic acid composition, and significantly increased linoleic, oleic, palmitic, stearic and arachidic acid composition in the Vge-1 accession. In Vge-4, palmitic acid composition was significantly increased. Results obtained suggested that the effect of EMS mutagenesis on fatty acid composition in vernonia could be accession-specific and influenced by mutation level. The significant but negative association between vernolic acid and other fatty acids indicates that there is potential to increase vernolic acid while at the same time reducing the contents of other fatty acids through EMS mutagenesis in vernonia. There is a need to assess EMS mutagenesis impact on seed oil over successive generations to confirm results from this study.

Optimising the dosage of ethyl methanesulphonate mutagenesis in selected wheat genotypes

Narrow genetic variation limits the success of crop improvement programs. Mutagenesis using ethyl methane- sulphonate (EMS) provides an opportunity to increase genetic variation to enhance selection in wheat improvement. This study aimed at establishing the optimum dosage and treatment conditions for EMS to induce genetic variation for drought tolerance and enhanced carbon sequestration in wheat. Seeds of three genotypes (LM29, LM43 and LM75) were treated with four EMS dosages (0, 0.1, 0.4 and 0.7% v/v) at three temperatures (25, 30 and 35 °C) for three exposure periods (1, 1.5 and 2 h) using three replicates. The ideal treatment conditions for effective mutagenesis were 0.7% EMS for 2 h at 35 °C for genotypes LM29 and LM43 and 0.4% EMS for 2 h at 25 °C for LM75. The estimated EMS dosages for LM43, LM29 and LM75 were 0.32%, 1.07% and 1.81% v/v EMS, respectively. This information can be used for large-scale mutation induction, exploration of new genetic variation, evaluation for genetic improvement and selection of mutant individuals for drought tolerance, high root–shoot biomass and carbon sequestration.

Physical and chemical mutagens improved Sporotrichum thermophile, strain ST20 for enhanced Phytase activity.

ObjectivePhosphorous is an essential micronutrient of plants and involved in critical biological functions. In nature, phosphorous is mostly present in immobilized inorganic mineral and in the fixed organic form including phytic acid and phosphoesteric compounds. However, the bioavailability of bound phosphorous could be enhanced by the use of phosphate solubilizing microorganisms such as bacteria and fungi. The phytases are widespread in an environment and have been isolated from different sources comprising bacteria and fungi.MethodologyIn current studies, we show the successful use of gamma rays and EMS (Ethyl Methane Sulphonate) mutagenesis for enhanced activity of phytases in a fungal strain Sporotrichum thermophile.ResultsWe report an improved strain ST2 that could produce a clear halo zone around the colony, up to 24 mm. The maximum enzymatic activity was found of 382 U/mL on pH 5.5. However, the phytase activity was improved to 387 U/ml at 45 °C. We also report that the mutants produced through EMS showed the greater potential for phytase production.ConclusionThe current study highlights the potential of EMS mutagenesis for strain improvement over physical mutagens.

Fine mapping of Aegilops peregrina co-segregating leaf and stripe rust resistance genes to distal-most end of 5DS.

Novel rust resistance genes LrP and YrP from Ae. peregrina identified on chromosome 5D and the linked markers will aid deployment of these genesin combination with other major/minor genes. Aegilops peregrina, a wild tetraploid relative of wheat with genome constitution UUSS, displays genetic variation for resistance to leaf and stripe (yellow) rust. The wheat Ae. peregrina introgression line, IL pau16058, harbouring leaf and stripe rust resistance, was crossed with wheat cv. WL711 to generate an F2:3 mapping population. Inheritance studies on this population indicated the transfer of dominant co-segregating resistance to leaf and stripe rust. Ethyl methane sulphonate mutagenesis of IL pau16058 identified independent loss-of-function mutants for leaf and stripe rust resistance, indicating that the leaf and stripe rust resistance is controlled by independent genes, herein designated LrP and YrP, respectively. A high-resolution genetic map of LrP and YrP was constructed using the Illumina Infinium iSelect 90K wheat array and resistance gene enrichment sequencing (RenSeq) markers. The map spans 4.19cM on the distal-most region of the short arm of chromosome 5D, consisting of eight SNP markers and one microsatellite marker. LrP and YrP co-segregated with markers BS00163889 and 5DS44573_snp and was flanked distally by the SNP marker BS00129707 and proximally by 5DS149010, defining a 15.71Mb region in the RefSeq v1.0 genome assembly.

OsACL-A2 negatively regulates cell death and disease resistance in rice.

Summary ATP‐citrate lyases (ACL) play critical roles in tumour cell propagation, foetal development and growth, and histone acetylation in human and animals. Here, we report a novel function of ACL in cell death‐mediated pathogen defence responses in rice. Using ethyl methanesulphonate (EMS) mutagenesis and map‐based cloning, we identified an Oryza sativa ACL‐A2 mutant allele, termed spotted leaf 30‐1 (spl30‐1), in which an A‐to‐T transversion converts an Asn at position 343 to a Tyr (N343Y), causing a recessive mutation that led to a lesion mimic phenotype. Compared to wild‐type plants, spl30‐1 significantly reduces ACL enzymatic activity, accumulates high reactive oxygen species and increases degradation rate of nuclear deoxyribonucleic acids. CRISPR/Cas9‐mediated insertion/deletion mutation analysis and complementation assay confirmed that the phenotype of spl30‐1 resulted from the defective function of OsACL‐A2 protein. We further biochemically identified that the N343Y mutation caused a significant degradation of SPL30N343Y in a ubiquitin‐26S proteasome system (UPS)‐dependent manner without alteration in transcripts of OsACL‐A2 in spl30‐1. Transcriptome analysis identified a number of up‐regulated genes associated with pathogen defence responses in recessive mutants of OsACL‐A2, implying its role in innate immunity. Suppressor mutant screen suggested that OsSL, which encodes a P450 monooxygenase protein, acted as a downstream key regulator in spl30‐1‐mediated pathogen defence responses. Taken together, our study discovered a novel role of OsACL‐A2 in negatively regulating innate immune responses in rice.

Genome-wide identification and expression profiling reveal tissue-specific expression and differentially-regulated genes involved in gibberellin metabolism between Williams banana and its dwarf mutant.

BackgroundDwarfism is one of the most valuable traits in banana breeding because semi-dwarf cultivars show good resistance to damage by wind and rain. Moreover, these cultivars present advantages of convenient cultivation, management, and so on. We obtained a dwarf mutant ‘8818-1’ through EMS (ethyl methane sulphonate) mutagenesis of Williams banana 8818 (Musa spp. AAA group). Our research have shown that gibberellins (GAs) content in 8818-1 false stems was significantly lower than that in its parent 8818 and the dwarf type of 8818-1 could be restored by application of exogenous GA3. Although GA exerts important impacts on the 8818-1 dwarf type, our understanding of the regulation of GA metabolism during banana dwarf mutant development remains limited.ResultsGenome-wide screening revealed 36 candidate GA metabolism genes were systematically identified for the first time; these genes included 3 MaCPS, 2 MaKS, 1 MaKO, 2 MaKAO, 10 MaGA20ox, 4 MaGA3ox, and 14 MaGA2ox genes. Phylogenetic tree and conserved protein domain analyses showed sequence conservation and divergence. GA metabolism genes exhibited tissue-specific expression patterns. Early GA biosynthesis genes were constitutively expressed but presented differential regulation in different tissues in Williams banana. GA oxidase family genes were mainly transcribed in young fruits, thus suggesting that young fruits were the most active tissue involved in GA metabolism, followed by leaves, bracts, and finally approximately mature fruits. Expression patterns between 8818 and 8818-1 revealed that MaGA20ox4, MaGA20ox5, and MaGA20ox7 of the MaGA20ox gene family and MaGA2ox7, MaGA2ox12, and MaGA2ox14 of the MaGA2ox gene family exhibited significant differential expression and high-expression levels in false stems. These genes are likely to be responsible for the regulation of GAs content in 8818-1 false stems.ConclusionOverall, phylogenetic evolution, tissue specificity and differential expression analyses of GA metabolism genes can provide a better understanding of GA-regulated development in banana. The present results revealed that MaGA20ox4, MaGA20ox5, MaGA20ox7, MaGA2ox7, MaGA2ox12, and MaGA2ox14 were the main genes regulating GA content difference between 8818 and 8818-1. All of these genes may perform important functions in the developmental processes of banana, but each gene may perform different functions in different tissues or during different developmental stages.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0809-1) contains supplementary material, which is available to authorized users.

Genetic improvement of two cultivars of Vicia faba L. using gamma irradiation and ethyl methanesulphonate mutagenesis

The present experiment was conducted to induce genetic variation using gamma irradiation and ethyl methanesulphonate mutagenesis and isolate and analyze the desirable mutant lines of Vicia faba L. var. Vikrant and PRT-12 in the M3 generation. The seeds of the mutant lines isolated from 3rd generation plants were analyzed for different parameters including total protein content, protein profiles and mineral content using Lowry method, Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and atomic absorption spectrophotometer, respectively. SDS-PAGE profile of mutants from variety Vikrant showed more polymorphism and expression of proteins than mutants isolated from variety PRT-12. Mutant seeds showed significantly higher protein content (0.18 to 1.29%) and mineral content (0.21 to 2.98 mg.g-1) compared to the controls. The mutants selected from variety Vikrant showed more increase in protein and mineral contents than the mutants selected from PRT-12. The selected mutant lines may serve as a valuable genetic material to breed for the improvement of protein and mineral contents in faba bean and other valuable crop plants.

Genome-wide comparison of ultraviolet and ethyl methanesulphonate mutagenesis methods for the brown alga Ectocarpus

Ectocarpus has emerged as a model organism for the brown algae and a broad range of genetic and genomic resources are being generated for this species. The aim of the work presented here was to evaluate two mutagenesis protocols based on ultraviolet irradiation and ethyl methanesulphonate treatment using genome resequencing to measure the number, type and distribution of mutations generated by the two methods. Ultraviolet irradiation generated a greater number of genetic lesions than ethyl methanesulphonate treatment, with more than 400 mutations being detected in the genome of the mutagenised individual. This study therefore confirms that the ultraviolet mutagenesis protocol is suitable for approaches that require a high density of mutations, such as saturation mutagenesis or Targeting Induced Local Lesions in Genomes (TILLING).

Agro-morphological variation among two selected wheat varieties after ethylmethanesulphonate mutagenesis

The study was aimed at investigating variations in agro-morphological traits of two selected wheat varieties after chemical mutagenesis using ethylmethanesulphonate (EMS). Two varieties (SST 56 and SST 875) were subjected to EMS mutagenesis using 0.5% v/v EMS at 32.5°C for 1 h. Field trials were carried out at Ukulinga Research Farm of the University of KwaZulu-Natal using a randomized complete block design with two replications. Data on nine important agro-morphological traits were collected and analyzed using the analysis of variance (ANOVA), correlation and principal component analysis (PCA) procedures. Significant variations were found among the agro-morphological traits between M1 individuals of the varieties after the mutagenesis compared to untreated checks. EMS significantly reduced seed germination in the field at 40% in both the varieties and significantly delayed days to heading by eight days. The mutagen caused a shortening of the days to maturity by 13 days in both the varieties. EMS treatment also significantly reduced plant height to 18 and 21cm in SST 56 and SST 875, respectively. The spike length was also reduced by ∼2.5 cm in both the varieties compared to control. 100-seed weight, flag leaf length and seeds per spike significantly increased in the treated seeds of both the varieties. Plant height had positive and significant correlation with number of tillers, number of seeds per spike, flag leaf length and 100-seed weight. However, it had negative correlation with the number of days to maturity. PCA revealed that three principal components (PC 1, PC 2 and PC 3) accounted to 57% of the total variations among the agro-morphological traits in both the varieties. PC 1 alone contributed to 27.7% of the variation which was correlated well with plant height (0.767), tiller number (0.812), number of seeds per spike (0.599) and seed yield (0.720). PC 2 explained 15.6% of the variation and well-correlated with germination percentage (0.784), spike length (0.554) and flag leaf length (0.772). PC 3 accounted to 12.4% of the variation and had negative correlation with days to maturity (−0.730). The study found that EMS had the potential to increase agro-morphological variations in wheat. This could be useful in selecting novel mutants with desired phenotypic traits.