Genetic diversity, population structure, and linkage disequilibrium of elite and local apple accessions from Belgium using the IRSC array

2017 ◽  
Vol 13 (6) ◽  
Author(s):  
Stijn Vanderzande ◽  
Diego Micheletti ◽  
Michela Troggio ◽  
Mark W. Davey ◽  
Johan Keulemans
BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Paul I. Otyama ◽  
Andrew Wilkey ◽  
Roshan Kulkarni ◽  
Teshale Assefa ◽  
Ye Chu ◽  
...  

Genes ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 676 ◽  
Author(s):  
Farahani ◽  
Maleki ◽  
Mehrabi ◽  
Kanouni ◽  
Scheben ◽  
...  

Characterization of genetic diversity, population structure, and linkage disequilibrium is a prerequisite for proper management of breeding programs and conservation of genetic resources. In this study, 186 chickpea genotypes, including advanced “Kabuli” breeding lines and Iranian landrace “Desi” chickpea genotypes, were genotyped using DArTseq-Based single nucleotide polymorphism (SNP) markers. Out of 3339 SNPs, 1152 markers with known chromosomal position were selected for genome diversity analysis. The number of mapped SNP markers varied from 52 (LG8) to 378 (LG4), with an average of 144 SNPs per linkage group. The chromosome size that was covered by SNPs varied from 16,236.36 kbp (LG8) to 67,923.99 kbp (LG5), while LG4 showed a higher number of SNPs, with an average of 6.56 SNPs per Mbp. Polymorphism information content (PIC) value of SNP markers ranged from 0.05 to 0.50, with an average of 0.32, while the markers on LG4, LG6, and LG8 showed higher mean PIC value than average. Unweighted neighbor joining cluster analysis and Bayesian-based model population structure grouped chickpea genotypes into four distinct clusters. Principal component analysis (PCoA) and discriminant analysis of principal component (DAPC) results were consistent with that of the cluster and population structure analysis. Linkage disequilibrium (LD) was extensive and LD decay in chickpea germplasm was relatively low. A few markers showed r2 ≥ 0.8, while 2961 pairs of markers showed complete LD (r2 = 1), and a huge LD block was observed on LG4. High genetic diversity and low kinship value between pairs of genotypes suggest the presence of a high genetic diversity among the studied chickpea genotypes. This study also demonstrates the efficiency of DArTseq-based SNP genotyping for large-scale genome analysis in chickpea. The genotypic markers provided in this study are useful for various association mapping studies when combined with phenotypic data of different traits, such as seed yield, abiotic, and biotic stresses, and therefore can be efficiently used in breeding programs to improve chickpea.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1116
Author(s):  
Vladimir Aleksandrov ◽  
Tania Kartseva ◽  
Ahmad M. Alqudah ◽  
Konstantina Kocheva ◽  
Krasimira Tasheva ◽  
...  

Genetic diversity and population structure are key resources for breeding purposes and genetic studies of important agronomic traits in crops. In this study, we described SNP-based genetic diversity, linkage disequilibrium and population structure in a panel of 179 bread wheat advanced cultivars and old accessions from Bulgaria, using an optimized wheat 25K Infinium iSelect array. Out of 19,019 polymorphic SNPs, 17,968 had а known chromosome position on the A (41%), B (42%) and D (11%) genome, and 6% were not assigned to any chromosome. Homoeologous group 4, in particular chromosome 4D, was the least polymorphic. In the total population, the Nei’s gene diversity was within the range 0.1-0.5, and the polymorphism information content ranged from 0.1 to 0.4. Significant differences between the old and modern collections were revealed with respect to the linkage disequilibrium (LD): the average values for LD (r2), the percentage of the locus pairs in LD and the LD decay were 0.64, 16% and 3.3 for the old germplasm, and 0.43, 30% and 4.1 for the modern releases, respectively. Structure and k-means clustering algorithm divided the panel into three groups. The old accessions formed a distinct subpopulation. The cluster analysis further distinguished the modern releases according to the geographic region and genealogy. Gene exchange was evidenced mainly between the subpopulations of contemporary cultivars. The achieved understanding of the genetic diversity and structure of the Bulgarian wheat population and distinctiveness of the old germplasm could be of interest for breeders developing cultivars with improved characteristics. The obtained knowledge about SNP informativeness and the LD estimation are worthwhile for selecting markers and for considering the composition of a population in association mapping studies of traits of interest.


2019 ◽  
Vol 12 (3) ◽  
pp. 180091 ◽  
Author(s):  
Desalegn D. Serba ◽  
Kebede T. Muleta ◽  
Paul St. Amand ◽  
Amy Bernardo ◽  
Guihua Bai ◽  
...  

2013 ◽  
Vol 126 (6) ◽  
pp. 1477-1486 ◽  
Author(s):  
Tobias Würschum ◽  
Simon M. Langer ◽  
C. Friedrich H. Longin ◽  
Viktor Korzun ◽  
Eduard Akhunov ◽  
...  

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 916-923 ◽  
Author(s):  
C. H. Bock ◽  
B. W. Wood ◽  
K. L. Stevenson ◽  
R. S. Arias

Fusicladium effusum causes pecan scab, which is the most destructive disease of pecan orchards in the United States. Conidia of the pathogen are spread by rain splash and wind. The fungus is pathogenically diverse; yet there is no information on its genetic diversity or population genetics. Universally primed polymerase chain reaction (UP-PCR) was used to investigate the genetic diversity and population structure on a hierarchical sample of 194 isolates collected from 11 orchard locations from Florida to Texas, consisting of three to four isolates from each of five to six trees at each location. Genetic variation was high throughout the region, with all but nine of the multilocus haplotypes being unique. Nei's average gene diversity ranged from 0.083 for a population from Mississippi to 0.160 for a population from Kansas. An analysis of molecular variance of the hierarchically sampled populations found that the majority of the genetic variability (82.6%) occurred at the scale of the individual tree and only relatively small amounts among populations in trees from an orchard (5.0%) or within groups (i.e., orchard location populations) (12.5%). The results suggest little population differentiation in F. effusum in the southeastern United States, although φpt values of genetic distance for pairwise comparisons indicated some populations could be differentiated from others. There was evidence of linkage disequilibrium in certain populations, and the common occurrence of asexual reproduction in F. effusum could lead to measurable linkage disequilibrium under certain circumstances. However, the degree of genetic diversity and the scale over which diversity is distributed is evidence that F. effusum undergoes regular recombination despite no known sexual stage.


2016 ◽  
Vol 15 (6) ◽  
pp. 515-526 ◽  
Author(s):  
Sofía E. Olmos ◽  
Verónica V. Lia ◽  
Guillermo H. Eyhérabide

AbstractKnowledge of linkage disequilibrium (LD) patterns is considered a prerequisite for effective association mapping studies. However, no LD analysis in the Argentine public temperate maize collection has been reported to date. In this study, a panel of 111 temperate maize inbreds genotyped at 74 single sequence repeats (SSRs) loci was used to assess LD, genetic diversity and population structure to evaluate the suitability of the panel for association mapping. Mini-core sets were also designed for in-depth phenotyping and allele mining purposes. The panel consisted of: (1) locally developed orange flint germplasm; (2) temperate inbred lines with Iowa Stiff Stalk Synthetic background; and (3) eight historic flint lines, some of them from the Cuarentín race. As a result, four subpopulations were defined. Joint analysis of population structure and combining ability allowed identifying two main heterotic patterns. High molecular diversity, a low extent of LD and a high ratio of linked to unlinked SSR loci pairs in significant LD were detected indicating the suitability of the entire collection for association mapping. The fact that the LD extent in the mini-core sets was similar to that observed in the entire collection and that only a small percentage of allelic richness was reduced suggests that these mini-core sets are suitable to capture diversity, exploit phenotypic variance and discover useful variants representative of the entire collection.


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