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Sansaloni, C.

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Sansaloni
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Sansaloni, C.

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Now showing 1 - 10 of 15
  • GWAS to identify genetic loci for resistance to yellow rust in wheat pre-breeding lines derived from diverse exotic crosses
    (Frontiers, 2019) Ledesma-Ramirez, L.; Solís Moya, E.; Iturriaga, G.; Sehgal, D.; Reyes-Valdés, M.H.; Montero-Tavera, V.; Sansaloni, C.; Burgueño, J.; Ortiz, C.; Aguirre-Mancilla, C.L.; Ramirez-Pimentel, J.G.; Vikram, P.; Singh, S.
    Publication
  • A wheat chromosome 5AL region confers seedling resistance to both tan spot and Septoria nodorum blotch in two mapping populations
    (Elsevier, 2019) Wenjing Hua; Xinyao He; Dreisigacker, S.; Sansaloni, C.; Juliana, P.; Singh, P.K.
    Tan spot (TS) and Septoria nodorum blotch (SNB), caused by Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively, are important fungal leaf-spotting diseases of wheat that cause significant losses in grain yield. In this study, two recombinant inbred line populations, ‘Bartai’ × ‘Ciano T79’ (referred to as B × C) and ‘Cascabel’ × ‘Ciano T79’ (C × C) were tested for TS and SNB response in order to determine the genetic basis of seedling resistance. Genotyping was performed with the DArTseq genotyping-by-sequencing (GBS) platform. A chromosome region on 5AL conferred resistance to TS and SNB in both populations, but the effects were larger in B × C (R2 = 11.2%–16.8%) than in C × C (R2 = 2.5%–9.7%). Additionally, the chromosome region on 5BL (presumably Tsn1) was significant for both TS and SNB in B × C but not in C × C. Quantitative trait loci (QTL) with minor effects were identified on chromosomes 1B, 2A, 2B, 3A, 3B, 4D, 5A, 5B, 5D, 6B, and 6D. The two CIMMYT breeding lines ‘Bartai’ and ‘Cascabel’ contributed resistance alleles at both 5AL and 5BL QTL mentioned above. The QTL on 5AL showed linkage with the Vrn-A1 locus, whereas the vrn-A1 allele conferring lateness was associated with resistance to TS and SNB.
    Publication
  • Genetic contribution of synthetic hexaploid wheat to CIMMYT’s spring bread wheat breeding germplasm
    (Nature Publishing Group, 2019) Rosyara, U.; Kishii, M.; Payne, T.S.; Sansaloni, C.; Singh, R.P.; Braun, H.J.; Dreisigacker, S.
    Synthetic hexaploid (SH) wheat (AABBD’D’) is developed by artificially generating a fertile hybrid between tetraploid durum wheat (Triticum turgidum, AABB) and diploid wild goat grass (Aegilops tauschii, D’D’). Over three decades, the International Maize and Wheat Improvement Center (CIMMYT) has developed and utilized SH wheat to bridge gene transfer from Ae. tauschii and durum wheat to hexaploid bread wheat. This is a unique example of success utilizing wild relatives in mainstream breeding at large scale worldwide. Our study aimed to determine the genetic contribution of SH wheat to CIMMYT’s global spring bread wheat breeding program. We estimated the theoretical and empirical contribution of D’ to synthetic derivative lines using the ancestral pedigree and marker information using over 1,600 advanced lines and their parents. The average marker-estimated D’ contribution was 17.5% with difference in genome segments suggesting application of differential selection pressure. The pedigree-based contribution was correlated with marker-based estimates without providing chromosome segment specific variation. Results from international yield trials showed that 20% of the lines were synthetic derived with an average D’ contribution of 15.6%. Our results underline the importance of SH wheat in maintaining and enhancing genetic diversity and genetic gain over years and is important for development of a more targeted introgression strategy. The study provides retrospective view into development and utilization of SH in the CIMMYT Global Wheat Program.
    Publication
  • Tracking the adoption of bread wheat varieties in Afghanistan using DNA fingerprinting
    (BioMed Central, 2019) Dreisigacker, S.; Sharma, R.; Huttner, E.; Karimov, A.; Obaidi, M.Q.; Singh, P.K.; Sansaloni, C.; Shrestha, R.; Sonder, K.; Braun, H.J.
    Wheat is the most important staple crop in Afghanistan and accounts for the main part of cereal production. However, wheat production has been unstable during the last decades and the country depends on seed imports. Wheat research in Afghanistan has emphasized releases of new, high-yielding and disease resistant varieties but rates of adoption of improved varieties are uncertain. We applied DNA fingerprinting to assess wheat varieties grown in farmers’ fields in four Afghan provinces. Of 560 samples collected from farmers’ fields during the 2015–16 cropping season, 74% were identified as varieties released after 2000, which was more than the number reported by farmers and indicates the general prevalence of use of improved varieties, albeit unknowingly. At the same time, we found that local varieties and landraces have been replaced and were grown by 4% fewer farmers than previously reported. In 309 cases (58.5%), farmers correctly identified the variety they were growing, while in 219 cases (41.5%) farmers. We also established a reference library of released varieties, elite breeding lines, and Afghan landraces, which confirms the greater genetic diversity of the landraces and their potential importance as a genetic resource. Our study is the first in wheat to apply DNA fingerprinting at scale for an accurate assessment of wheat varietal adoption and our findings point up the importance of DNA fingerprinting for accuracy in varietal adoption studies.
    Publication
  • Genome-wide genetic diversity and population structure of tunisian durum wheat landraces based on DArTseq technology
    (MDPI, 2019) Robbana, C.; Kehel, Z.; Ben Naceur, M.; Sansaloni, C.; Bassi, F.; Amri, A.
    Tunisia, being part of the secondary center of diversity for durum wheat, has rich unexploited landraces that are being continuously lost and replaced by high yielding modern cultivars. This study aimed to investigate the genetic diversity and population structure of 196 durum wheat lines issued from landraces collected from Tunisia using Diversity Array Technology sequencing (DArTseq) and to understand possible ways of introduction in comparing them to landraces from surrounding countries. A total of 16,148 polymorphic DArTseq markers covering equally the A and B genomes were effective to assess the genetic diversity and to classify the accessions. Cluster analysis and discriminant analysis of principal components (DAPC) allowed us to distinguish five distinct groups that matched well with the farmer's variety nomenclature. Interestingly, Mahmoudi and Biskri landraces constitute the same gene pool while Jenah Zarzoura constitutes a completely different group. Analysis of molecular variance (AMOVA) showed that the genetic variation was among rather than within the landraces. DAPC analysis of the Tunisian, Mediterranean and West Asian landraces confirmed our previous population structure and showed a genetic similarity between the Tunisian and the North African landraces with the exception of Jenah Zarzoura being the most distant. The genomic characterization of the Tunisian collection will enhance their conservation and sustainable use.
    Publication
  • An informational view of accession rarity and allele specificity in germplasm banks for management and conservation
    (Public Library of Science, 2018) Reyes-Valdés, M.H.; Burgueño, J.; Singh, S.; Martinez, O.; Sansaloni, C.
    Germplasm banks are growing in their importance, number of accessions and amount of characterization data, with a large emphasis on molecular genetic markers. In this work, we offer an integrated view of accessions and marker data in an information theory framework. The basis of this development is the mutual information between accessions and allele frequencies for molecular marker loci, which can be decomposed in allele specificities, as well as in rarity and divergence of accessions. In this way, formulas are provided to calculate the specificity of the different marker alleles with reference to their distribution across accessions, accession rarity, defined as the weighted average of the specificity of its alleles, and divergence, defined by the Kullback-Leibler formula. Albeit being different measures, it is demonstrated that average rarity and divergence are equal for any collection. These parameters can contribute to the knowledge of the structure of a germplasm collection and to make decisions about the preservation of rare variants. The concepts herein developed served as the basis for a strategy for core subset selection called HCore, implemented in a publicly available R script. As a proof of concept, the mathematical view and tools developed in this research were applied to a large collection of Mexican wheat accessions, widely characterized by SNP markers. The most specific alleles were found to be private of a single accession, and the distribution of this parameter had its highest frequencies at low levels of specificity. Accession rarity and divergence had largely symmetrical distributions, and had a positive, albeit non-strictly linear relationship. Comparison of the HCore approach for core subset selection, with three state-of-the-art methods, showed it to be superior for average divergence and rarity, mean genetic distance and diversity. The proposed approach can be used for knowledge extraction and decision making in germplasm collections of diploid, inbred or outbred species.
    Publication
  • Mapping QTLs conferring additive resistance to Karnal bunt in bread wheat in two RIL populations
    (CIMMYT, 2018) Gurcharn S. Brar; Fuentes Dávila, G.; Xinyao He; Singh, R.P.; Sansaloni, C.; Singh, P.K.
    Publication
  • Genetic mapping of resistance in hexaploid wheat for a quarantine disease: karnal bunt
    (Frontiers, 2018) Gurcharn S. Brar; Fuentes Dávila, G.; Xinyao He; Sansaloni, C.; Singh, R.P.; Singh, P.K.
    Karnal bunt (KB) of wheat, caused by Tilletia indica, is one of the greatest challenges to grain industry, not because of yield loss, but quarantine regulations that restrict international movement and trade of affected stocks. Genetic resistance is the best way to manage this disease. Although several different sources of resistance have been identified to date, very few of those have been subjected to genetic analyses. Understanding the genetics of resistance, characterization and mapping of new resistance loci can help in development of improved germplasm. The objective of this study was to identify and characterize resistance loci (QTL) in two independent recombinant inbred lines (RILs) populations utilizing different wheat lines as resistance donors. Elite CIMMYT wheat lines Blouk#1 and Huirivis#1 were used as susceptible female parents and WHEAR/KUKUNA/3/C80.1/3BATAVIA//2WBLL1 (WKCBW) and Mutus as moderately resistant male parents in Pop1 and Pop2 populations, respectively. Populations were evaluated for KB resistance in 2015–16 and 2016–17 cropping seasons at two seeding dates (total four environments) in Cd. Obregon, Mexico. Two stable QTL from each population were identified in each environment: QKb.cim-2B and QKb.cim-3D (Pop1), QKb.cim-3B1 and QKb.cim-5B2 (Pop2). Other than those four QTL, other QTL were detected in each population which were specific to environments: QKb.cim-5B1, QKb.cim-6A, and QKb.cim-7A (Pop1), QKb.cim-3B2, QKb.cim-4A1, QKb.cim-4A2, QKb.cim-4B, QKb.cim-5A1, QKb.cim-5A2, and QKb.cim-7A2 (Pop2). Among the four stable QTL, all but QKb.cim-3B1 were derived from the resistant parent. QKb.cim-2B and QKb.cim-3D in Pop1 and QKb.cim-3B1 and QKb.cim-5B2 in Pop2 explained 5.0–11.4% and 3.3–7.1% phenotypic variance, respectively. A combination of two stable QTL in each population reduced KB infection by 24–33%, respectively. Transgressive resistant segregants lines derived with resistance alleles from both parents in each population were identified. Single nucleotide polymorphism (SNP) markers flanking these QTL regions may be amenable to marker-assisted selection. The best lines from both populations (in agronomy, end-use quality and KB resistance) carrying resistance alleles at all identified loci, may be used for inter-crossing and selection of improved germplasm in future. Markers flanking these QTL may assist in selection of such lines.
    Publication
  • Resistance to spot blotch in two mapping populations of common wheat is controlled by multiple QTL of minor effects
    (MDPI, 2018) Singh, P.K.; Xinyao He; Sansaloni, C.; Juliana, P.; Dreisigacker, S.; Duveiller, E.; Kumar, U.; Joshi, A.K.; Singh, R.P.
    Spot blotch (SB) is an important fungal disease of wheat in South Asia and South America. Host resistance is regarded as an economical and environmentally friendly approach of controlling SB, and the inheritance of resistance is mostly quantitative. In order to gain a better understanding on the SB resistance echanism in CIMMYT germplasm, two bi-parental mapping populations were generated, both comprising 232 F2:7 progenies. Elite CIMMYT breeding lines, BARTAI and WUYA, were used as resistant parents, whereas CIANO T79 was used as susceptible parent in both populations. The two populations were evaluated for field SB resistance at CIMMYT’s Agua Fria station for three consecutive years, from the 2012–2013 to 2014–2015 cropping seasons. Phenological traits like plant height (PH) and days to heading (DH) were also determined. Genotyping was performed using the DArTSeq genotyping-by-sequencing (GBS) platform, and a few D-genome specific SNPs and those for phenological traits were integrated for analysis. The most prominent quantitative trait locus (QTL) in both populations was found on chromosome 5AL at the Vrn-A1 locus, explaining phenotypic variations of 7–27%. Minor QTL were found on chromosomes 1B, 3A, 3B, 4B, 4D, 5B and 6D in BARTAI and on chromosomes 1B, 2A, 2D and 4B in WUYA, whereas minor QTL contributed by CIANO T79 were identified on chromosome 1B, 1D, 3A, 4B and 7A. In summary, resistance to SB in the two mapping populations was controlled by multiple minor QTL, with strong influence from Vrn-A1.
    Publication
  • Harnessing genetic potential of wheat germplasm banks through impact-oriented-prebreeding for future food and nutritional security
    (Nature Publishing Group, 2018) Singh, S.; Vikram, P.; Sehgal, D.; Burgueño, J.; Sharma, A.R.; Singh, S.K.; Sansaloni, C.; Joynson, R.; Brabbs, T.; Ortiz, C.; Solís Moya, E.; Velu, G.; Gupta, N.; Sidhu, H.S.; Basandrai, A.K.; Basandrai, D.; Ledesma-Ramires, L.; Suaste-Franco, M.P.; Fuentes Dávila, G.; Ireta Moreno, J.; Sonder, K.; Vaibhav K. Singh; Sajid Shokat; Shokat, S.; Mian A. R. Arif; Khalil A. Laghari; Puja Srivastava; Bhavani, S.; Satish Kumar; Pal, D.; Jaiswal, J.P.; Kumar, U.; Harinder K. Chaudhary; Crossa, J.; Payne, T.S.; Imtiaz, M.; Sohu, V.S.; Singh, G.P.; Bains, N.; Hall, A.J.W.; Pixley, K.V.
    The value of exotic wheat genetic resources for accelerating grain yield gains is largely unproven and unrealized. We used next-generation sequencing, together with multi-environment phenotyping, to study the contribution of exotic genomes to 984 three-way-cross-derived (exotic/elite1//elite2) pre-breeding lines (PBLs). Genomic characterization of these lines with haplotype map-based and SNP marker approaches revealed exotic specific imprints of 16.1 to 25.1%, which compares to theoretical expectation of 25%. A rare and favorable haplotype (GT) with 0.4% frequency in gene bank identified on chromosome 6D minimized grain yield (GY) loss under heat stress without GY penalty under irrigated conditions. More specifically, the ‘T’ allele of the haplotype GT originated in Aegilops tauschii and was absent in all elite lines used in study. In silico analysis of the SNP showed hits with a candidate gene coding for isoflavone reductase IRL-like protein in Ae. tauschii. Rare haplotypes were also identified on chromosomes 1A, 6A and 2B effective against abiotic/biotic stresses. Results demonstrate positive contributions of exotic germplasm to PBLs derived from crosses of exotics with CIMMYT’s best elite lines. This is a major impact-oriented pre-breeding effort at CIMMYT, resulting in large-scale development of PBLs for deployment in breeding programs addressing food security under climate change scenarios.
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