Genomic Regions Influencing Preharvest Sprouting Tolerance in Two Doubled-Haploid Wheat Populations (Triticum aestivum L.)

2021 ◽  
Author(s):  
Thobeka Philile Khumalo ◽  
Tsepiso Hlongoane ◽  
Annelie Barnard ◽  
Toi John Tsilo
Keyword(s):  
Climate Change ◽  
Single Nucleotide Polymorphism ◽  
Doubled Haploid ◽  
Triticum Aestivum L ◽  
Preharvest Sprouting ◽  
Economic Losses ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Dh Lines ◽  
Genomic Regions

The current and projected climate change that is represented by increasing temperatures, humidity levels and irregular rainfall patterns, promotes the occurrence of preharvest sprouting (PHS) in wheat. PHS results in significant economic losses, globally, which necessitates the need for high-yielding cultivars with increased PHS tolerance, hence this study was conducted. The current study evaluated two doubled-haploid (DH) wheat populations of Tugela-Dn × Elands and Elands × Flamink across six environments in the Free State Province of South Africa to select genotypes with increased PHS tolerance and further map the underlying loci. Significant effects of DH lines (194) and environments (6) were observed for PHS tolerance. The results of this study validate previous findings that PHS is only expressed when environmental conditions are conducive. Quantitative trait loci (QTL) mapping using single nucleotide polymorphism (SNP) and silicoDArT markers revealed three additive QTL with major effects on chromosomes 5B and 7B, and these QTL were detected more than once, when conditions were favourable. These QTL explained a phenotypic variation (PVE) varying between 10.08% and 20.30% (LOD = 2.73 – 3.11). About 16.50% of DH lines performed to the level of Elands (the PHS-tolerant parent) and are recommended for further selection in a pre-breeding or breeding programme. The findings of the study are expected to facilitate the on-going breeding efforts for PHS tolerance in winter wheat.

scholarly journals Genome-Wide Linkage Mapping for Preharvest Sprouting Resistance in Wheat Using 15K Single-Nucleotide Polymorphism Arrays

2021 ◽  
Vol 12 ◽  
Author(s):  
Lingli Li ◽  
Yingjun Zhang ◽  
Yong Zhang ◽  
Ming Li ◽  
Dengan Xu ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Linkage Mapping ◽  
Cost Effective ◽  
Wheat Breeding ◽  
Preharvest Sprouting ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Specific Pcr ◽  
Grain Color ◽  
Sprouting Resistance

Preharvest sprouting (PHS) significantly reduces grain yield and quality. Identification of genetic loci for PHS resistance will facilitate breeding sprouting-resistant wheat cultivars. In this study, we constructed a genetic map comprising 1,702 non-redundant markers in a recombinant inbred line (RIL) population derived from cross Yangxiaomai/Zhongyou9507 using the wheat 15K single-nucleotide polymorphism (SNP) assay. Four quantitative trait loci (QTL) for germination index (GI), a major indicator of PHS, were identified, explaining 4.6–18.5% of the phenotypic variances. Resistance alleles of Qphs.caas-3AL, Qphs.caas-3DL, and Qphs.caas-7BL were from Yangxiaomai, and Zhongyou9507 contributed a resistance allele in Qphs.caas-4AL. No epistatic effects were detected among the QTL, and combined resistance alleles significantly increased PHS resistance. Sequencing and linkage mapping showed that Qphs.caas-3AL and Qphs.caas-3DL corresponded to grain color genes Tamyb10-A and Tamyb10-D, respectively, whereas Qphs.caas-4AL and Qphs.caas-7BL were probably new QTL for PHS. We further developed cost-effective, high-throughput kompetitive allele-specific PCR (KASP) markers tightly linked to Qphs.caas-4AL and Qphs.caas-7BL and validated their association with GI in a test panel of cultivars. The resistance alleles at the Qphs.caas-4AL and Qphs.caas-7BL loci were present in 72.2 and 16.5% cultivars, respectively, suggesting that the former might be subjected to positive selection in wheat breeding. The findings provide not only genetic resources for PHS resistance but also breeding tools for marker-assisted selection.

scholarly journals Selection signatures in two oldest Russian native cattle breeds revealed using high-density single nucleotide polymorphism analysis

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242200
Author(s):  
Natalia Anatolievna Zinovieva ◽  
Arsen Vladimirovich Dotsev ◽  
Alexander Alexandrovich Sermyagin ◽  
Tatiana Evgenievna Deniskova ◽  
Alexandra Sergeevna Abdelmanova ◽  
...  
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Candidate Genes ◽  
High Density ◽  
Fixation Index ◽  
Nucleotide Polymorphism ◽  
Selection Signatures ◽  
Single Nucleotide ◽  
Cattle Breeds ◽  
Native Cattle ◽  
Genomic Regions

Native cattle breeds can carry specific signatures of selection reflecting their adaptation to the local environmental conditions and response to the breeding strategy used. In this study, we comprehensively analysed high-density single nucleotide polymorphism (SNP) genotypes to characterise the population structure and detect the selection signatures in Russian native Yaroslavl and Kholmogor dairy cattle breeds, which have been little influenced by introgression with transboundary breeds. Fifty-six samples of pedigree-recorded purebred animals, originating from different breeding farms and representing different sire lines, of the two studied breeds were genotyped using a genome-wide bovine genotyping array (Bovine HD BeadChip). Three statistical analyses—calculation of fixation index (FST) for each SNP for the comparison of the pairs of breeds, hapFLK analysis, and estimation of the runs of homozygosity (ROH) islands shared in more than 50% of animals—were combined for detecting the selection signatures in the genome of the studied cattle breeds. We confirmed nine and six known regions under putative selection in the genomes of Yaroslavl and Kholmogor cattle, respectively; the flanking positions of most of these regions were elucidated. Only two of the selected regions (localised on BTA 14 at 24.4–25.1 Mbp and on BTA 16 at 42.5–43.5 Mb) overlapped in Yaroslavl, Kholmogor and Holstein breeds. In addition, we detected three novel selection sweeps in the genome of Yaroslavl (BTA 4 at 4.74–5.36 Mbp, BTA 15 at 17.80–18.77 Mbp, and BTA 17 at 45.59–45.61 Mbp) and Kholmogor breeds (BTA 12 at 82.40–81.69 Mbp, BTA 15 at 16.04–16.62 Mbp, and BTA 18 at 0.19–1.46 Mbp) by using at least two of the above-mentioned methods. We expanded the list of candidate genes associated with the selected genomic regions and performed their functional annotation. We discussed the possible involvement of the identified candidate genes in artificial selection in connection with the origin and development of the breeds. Our findings on the Yaroslavl and Kholmogor breeds obtained using high-density SNP genotyping and three different statistical methods allowed the detection of novel putative genomic regions and candidate genes that might be under selection. These results might be useful for the sustainable development and conservation of these two oldest Russian native cattle breeds.

UTILIZATION OF DNA MARKERS FOR EVALUATING AMYLOSE CONTENT OF GRAIN IN RICE

2013 ◽  
Vol 83 (5) ◽  
Author(s):  
Dương Thanh Thủy ◽  
Taiichiro Ookawa
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Amylose Content ◽  
Waxy Gene ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Branching Enzymes ◽  
Wx Gene ◽  
High Amylose ◽  
Suitable Marker ◽  
Granule Bound Starch Synthase

The sensory and functional properties of rice are predominantly associated with its amylose content. Granule-bound starch synthase (GBSS) encoded by the Waxy (Wx) gene determines the synthesis of amylose, while starch branching enzymes encoded by Sbe genes are involved in the formation of amylopectin. Some studies have demonstrated that Wx gene is the major controller of amylose content but there are one or more modifying genes affecting the amylose content. Three markers,  microsatellite, Single – nucleotide – polymorphism (G/T SNP) in Wx gene and Single – nucleotide – polymorphism (T/C SNP) in Sbe1 gene, were tested for their association with amylose content using sixty-nine  rice accessions from twenty countries. Of the three markers, two markers in Wx gene are significantly associated with amylose content. The combination of two markers in Wx gene (haplotypes) explained 83.8% of the variation in amylose content and discriminated the three market classes of glutinous, low, intermediate and high amylose content of rice from each other. And T/C SNP in Sbe1 locus was not a suitable marker for amylose content. Keywords: marker, amylose content, Waxy gene.

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