| 1. |
- Mulugeta, Behailu, et al.
(author)
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Harnessing genome-wide genetic diversity, population structure and linkage disequilibrium in Ethiopian durum wheat gene pool
- 2023
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In: Frontiers in Plant Science. - 1664-462X.
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Journal article (peer-reviewed)abstract
- Yanyang Liu, Henan Academy of Agricultural Sciences (HNAAS), China; Landraces are an important genetic source for transferring valuable novel genes and alleles required to enhance genetic variation. Therefore, information on the gene pool’s genetic diversity and population structure is essential for the conservation and sustainable use of durum wheat genetic resources. Hence, the aim of this study was to assess genetic diversity, population structure, and linkage disequilibrium, as well as to identify regions with selection signature. Five hundred (500) individuals representing 46 landraces, along with 28 cultivars were evaluated using the Illumina Infinium 25K wheat SNP array, resulting in 8,178 SNPs for further analysis. Gene diversity (GD) and the polymorphic information content (PIC) ranged from 0.13–0.50 and 0.12–0.38, with mean GD and PIC values of 0.34 and 0.27, respectively. Linkage disequilibrium (LD) revealed 353,600 pairs of significant SNPs at a cut-off (r2 > 0.20, P < 0.01), with an average r2 of 0.21 for marker pairs. The nucleotide diversity (π) and Tajima’s D (TD) per chromosome for the populations ranged from 0.29–0.36 and 3.46–5.06, respectively, with genome level, mean π values of 0.33 and TD values of 4.43. Genomic scan using the Fst outlier test revealed 85 loci under selection signatures, with 65 loci under balancing selection and 17 under directional selection. Putative candidate genes co-localized with regions exhibiting strong selection signatures were associated with grain yield, plant height, host plant resistance to pathogens, heading date, grain quality, and phenolic content. The Bayesian Model (STRUCTURE) and distance-based (principal coordinate analysis, PCoA, and unweighted pair group method with arithmetic mean, UPGMA) methods grouped the genotypes into five subpopulations, where landraces from geographically non-adjoining environments were clustered in the same cluster. This research provides further insights into population structure and genetic relationships in a diverse set of durum wheat germplasm, which could be further used in wheat breeding programs to address production challenges sustainably.
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| 2. |
- Mulugeta, Behailu, et al.
(author)
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Marker-trait association analyses revealed major novel QTLs for grain yield and related traits in durum wheat
- 2023
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In: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 13
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Journal article (peer-reviewed)abstract
- The growing global demand for wheat for food is rising due to the influence of population growth and climate change. The dissection of complex traits by employing a genome-wide association study (GWAS) allows the identification of DNA markers associated with complex traits to improve the productivity of crops. We used GWAS with 10,045 single nucleotide polymorphism (SNP) markers to search for genomic regions associated with grain yield and related traits based on diverse panels of Ethiopian durum wheat. In Ethiopia, multi-environment trials of the genotypes were carried out at five locations. The genotyping was conducted using the 25k Illumina Wheat SNP array to explore population structure, linkage disequilibrium (LD), and marker-trait associations (MTAs). For GWAS, the multi-locus Fixed and Random Model Circulating Probability Unification (FarmCPU) model was applied. Broad-sense heritability estimates were high, ranging from 0.63 (for grain yield) to 0.97 (for thousand-kernel weight). The population structure based on principal component analysis, and model-based cluster analysis revealed two genetically distinct clusters with limited admixtures. The LD among SNPs declined within the range of 2.02-10.04 Mbp with an average of 4.28 Mbp. The GWAS scan based on the mean performance of the genotypes across the environments identified 44 significant MTAs across the chromosomes. Twenty-six of these MTAs are novel, whereas the remaining 18 were previously reported and confirmed in this study. We also identified candidate genes for the novel loci potentially regulating the traits. Hence, this study highlights the significance of the Ethiopian durum wheat gene pool for improving durum wheat globally. Furthermore, a breeding strategy focusing on accumulating favorable alleles at these loci could improve durum wheat production in the East African highlands and elsewhere.
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| 3. |
- Ortiz Rios, Rodomiro Octavio, et al.
(author)
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Hydroponic optimization and screening of aluminum tolerance on finger millet (Eleusine coracana (L.) Gaertn.) accessions and cultivars
- 2023
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In: Agronomy. - 2073-4395. ; 13
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Journal article (peer-reviewed)abstract
- Finger millet (Eleusine coracana (L.) Gaertn.) is an annual allotetraploid that belongs to the grass family Poaceae subfamily Chloridoideae. Using less productive cultivars, biotic and abiotic stresses affect the yield and productivity of finger millet in Ethiopia. This research was aimed at investigating the acidity/Al tolerance of 328 finger millet accessions and 15 cultivars from Ethiopia and Zimbabwe. Prior to screening the accessions, optimization was performed on 15 cultivars and 15 accessions under three Al concentrations (0, 75, and 100 µM), and, afterward, 100 µM of Al concentration was selected as the threshold level. Root length (RL) and shoot length (SL) were recorded after 10 days of treatment. Accessions 215836, 215845, and 229722 and cultivars Urji, Bareda, and Axum were found Al-tolerant, while cultivars Tadesse, Padet, and Kumsa and accessions 212462, 215804, and 238323 were found Al-susceptible. ANOVA on RL indicated that the variance due to environment (42.3) was higher than genotypic variance (0.37). Whereas, the ANOVA on SL indicated the variance due to environment was not significant, and genotypic variance (0.18) was higher than environmental (0.02). RL was highly affected due to Al stress, while no distinct and visible symptoms were observed on SL. Furthermore, the screening of 328 accessions under 100 µM and the control resulted in Al-tolerant (n = 20), intermediate (225), and Al-susceptible (83). The results of the present study reveal that the presence of acid-tolerant accessions can be used as inputs for breeders to improve the productivity of finger millet in acidic areas.
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