Plant breeding relies on genetic variation to produce new and improved cultivars. One way to obtain novel traits is by inducing mutations. The present study aimed to create a Fusarium crown rot (FCR) and Fusarium head blight (FHB)-resistant mutagenized wheat population using ethyl methane sulphonate (EMS) and identify mutant resistance to FCR and FHB, which could provide a starting point for resistance breeding. The optimal mutagenesis conditions were determined based on the germination percentage. This study used six Chinese wheat cultivars, namely Jimai22, Hengguan35, Shixin828, Gaoyou2018, Keiwei20, and Keiwei18, to create a mutant population by treating them with EMS. For Shixin828, the optimal condition was 0.8% EMS with a 50-55% germination rate. For Hengguan35 and Jimai22, it was 0.6% EMS. For Gaoyou2018 and Kewei20, it was 0.8% and 0.4-0.6%, respectively. The FCR disease index of the mutant lines (M1) ranged from 10.00 to 77.67. For M2, the number of individual mutant plants demonstrating resistance to FCR varied from 76 to 102. In M3, 570 healthy plants were obtained using various EMS concentrations. The mutant line Kewei18 demonstrated the most resistance to FCR, FHB, and Deoxynivalenol (DON) infection. Kewei20 mutants had a higher FHB susceptibility than other mutants. Overall, mutants from the Kewei18 genetic background displayed better disease resistance to both diseases and DON contamination than natural plants. Mutants with or moderate resistance to FCR and FHB could be used in breeding and genetic studies to identify FHB and FCR-resistant Quantitative Trait Locus (QTL) in wheat.
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Mutation is an effective strategy not only for creating novel variation into crop genome but also for direct releasing adapted and high-yielding genotypes. The current work explores inducing genetic variability in bread wheat using physical and chemical mutagens. Three wheat cultivars were treated by three mutagens; gamma irradiation (five doses; 250, 300, 350, 400 and 450 Gray); laser ray (three treatments; 1, 1.5, and 2 hour exposure) and EMS (three concentrations; 0.2, 0.3 and 0.4%). Besides, a combination of physical (laser) and chemical (EMS) mutagens using middle range of each treatment (1.5 hour laser and 0.3% EMS) was attempted to be applied. The treated seeds were sown in the first season and 4050 M1 plants were harvested. The harvested seeds were sown in the second season, and 78750 M2 plants were obtained. The selection was performed in second season (M2) based on morpho-physiological and yield traits; flag leaf area, flag leaf chlorophyll content, plant height, spike length, grain yield per plant and its components. Based on evaluated traits fourteen mutants were selected to be evaluated in the third generation (M3). The results indicated that the used mutagens had direct impact and significantly improved agronomic traits in derivative mutants compared to their parent cultivars. Moreover, the maximum increment in yield related traits were obtained by 0.4% EMS, 1 and 2 hour-laser, 350-Gy, 1.5 hour × 0.3% EMS and 250-Gy. The obtained results highlighted the importance of these doses of applied mutagens to induce useful genetic variability in bread wheat for improving grain yield and contributing traits.
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The integration of advanced technologies into breeding programs in the 21st century can result in a powerful step change in crop productivity when aligned with components of genetic gain. Genetic gain depends upon four factors: accuracy, selection intensity, genetic variation, and time. It is a useful starting point, as it articulates the parameters breeders operate as part of the crop improvement process. This review article has compiled advanced breeding technologies such as phenomics, genotyping and se-quencing platforms, genome editing, and double haploid, which can be applied to each component of the genetic gain equation. In addition, it has explained the strategies, opportunities, and limitations in order to support breeders in making wise decisions in regard to the technologies and therefore increase efficiency with the breeding programs.
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In order to understand the genetic variation of the cultivated and weedy types of
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