Everbearing strawberry cultivars provide fruit during the summer–fall period when June-bearing strawberries are unavailable, but their breeding progress has been constrained by complex trait interactions. To characterize segregation patterns and evaluate phenotypic diversity, we developed an F₁ population from a cross between two everbearing cultivars, ‘Charlotte’ and ‘Flamenco’. Twenty selected progenies were evaluated for 30 quantitative traits encompassing vegetative vigor, inflorescence structure, fruit morphology, firmness, and biochemical composition. Substantial variation was observed among lines, with several individuals exceeding parental performance for key traits such as fruit size, soluble solids content, and sucrose accumulation. Principal component analysis revealed three major axes of variation: fruit composition (sugars and acids), vegetative vigor, and fruit size and morphology. K-means clustering grouped the progeny into three phenotypic classes, representing high-sugar, large-fruited, or vigorous growth types. Notably, some lines combined favorable attributes across classes, such as high sweetness and large fruit, indicating the potential to overcome typical trade-offs between yield and quality. These findings provide a practical framework for breeding selection and highlight superior progeny as immediate candidates for clonal advancement or as parents in future crossing. The results also establish a foundation for integrating phenotypic classifications with molecular tools to accelerate the development of high-value everbearing strawberries.
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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The genus
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Morphological variation was investigated among 31 maize landrace accessions collected from the fields of various farmers in South Sudan by examining 7 quantitative agronomic characteristics. A significant positive correlation was found between days to tasseling (DT) and days to silking (DS), between plant height (PH) and ear height (EH) and stem width (SW), and between EH and SW and leaf length (LL). First and second principal components accounted for 69% of the total variance (40.9% and 28.6%, respectively). PH, EH, SW, LL, and leaf width (LW) were clearly characterized in a positive direction on the first axis. DT and DS were clearly characterized in a positive direction on the second axis. A scatter plot based on phenotypic data revealed the existence of 3 groups based on the most discriminating characteristics: Group I included 5 maize landrace accessions, Group II comprised 14 maize landrace accessions, and Group III included 10 maize landrace accessions. In principal component analysis, generally the investigated genotypes were not clearly grouped into their geographical origins owing to a weak geographic relationship among the accessions. In conclusion, even though the morphological characterization studies were conducted in the South Korean climate, this study revealed significant phenotypic variation among the explored maize landrace accessions collected from South Sudan. Therefore, this information about phenotypic divergence may be very useful for future breeding research programs as well as for genetic improvement of South Sudan maize accessions.
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Rice (
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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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Thirty-six okra germplasms were grown and evaluated for yield and yield related traits at the Department of Plant Breeding and Genetics, Vellayani, Trivandrum, Kerala. The germplasms studied possessed sufficient variability for all the traits. High genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were noticed for almost all characters and narrow difference between GCV and PCV suggest that environmental influence is minimal for the traits studied. High estimates of heritability coupled with high to moderate genetic advance as percent over mean was recorded for all the characters considered. Yield had positive and significant association with number of fruits per plant, fruit weight, fruit girth and number of primary branches indicating that selection based on these characters may improve yield. Principal component analysis indicated that first three principal components contributed for sixty percent total variation among ten characters describing accessions. The cluster analysis revealed that hybridization of cluster I with cluster IV would be beneficial to develop promising varieties under diverse climatic conditions in India.
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In order to understand the genetic variation of the cultivated and weedy types of
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Phenotypic variation within organisms is driven primarily by genetic diversity. However, there is a growing appreciation that epigenetic variation, resulting from a multitude of diverse chemical modifications to the DNA and chromatin, can have profound effects on phenotype. Heritable epigenetic marks persist through meiosis and can be stably transmitted to the next generation, resulting in transgenerational epigenetic inheritance. Importantly, when epigenetic changes occur near coding genes, affecting their transcriptional state, heritable epigenetic variation can result in heritable phenotypic variation. Large-scale interrogation of epigenome inheritance in Arabidopsis has revealed that spontaneous variation in DNA methylation occurs at a rate that is orders of magnitude greater than genetic mutation, indicating the key importance of epigenetic variation during evolution. Thus, there is a potential for epigenetics to play a role in crop improvement, including regulation of transgene expression and creation of novel epialleles. Here, we review cases of naturally occurring and genetically induced epialleles, and discuss how the studies from two epigenetic populations are rapidly increasing our understanding of epigenetic diversity.
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