Person: Ogbonnaya, F.C.
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Ogbonnaya
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F.C.
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Ogbonnaya, F.C.
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0000-0002-8596-7362 9 results
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- Genome-wide analyses reveal footprints of divergent selection and drought adaptive traits in synthetic-derived wheats(Genetics Society of America, 2019) Afzal, F.; Huihui Li; Gul, A.; Subhani, A.; Ahmad Ali; Mujeeb-Kazi, A.; Ogbonnaya, F.C.; Trethowan, R.; Xianchun Xia; He Zhonghu; Rasheed, A.
Publication - Unravelling the complex genetics of karnal bunt (Tilletia indica) resistance in common wheat (Triticum aestivum) by genetic linkage and genome-wide association analyses(Genetics Society of America, 2019) Emebiri, L.C.; Singh, S.; Tan, M.K.; Singh, P.K.; Fuentes Dávila, G.; Ogbonnaya, F.C.Karnal bunt caused by Tilletia indica Mitra [syn. Neovossia indica (Mitra) Mundkur] is a significant biosecurity concern for wheat-exporting countries that are free of the disease. It is a seed-, soil-and air-borne disease with no effective chemical control measures. The current study used data from multi-year field experiments of two bi-parental populations and a genome-wide association (GWA) mapping panel to unravel the genetic basis for resistance in common wheat. Broad-sense heritability for Karnal bunt resistance in the populations varied from 0.52 in the WH542×HD29 population, to 0.61 in the WH542×W485 cross and 0.71 in a GWAS panel. Quantitative trait locus (QTL) analysis with seven years of phenotypic data identified a major locus on chromosome 3B (R2 = 27.8%) and a minor locus on chromosome 1A (R2 = 12.2%), in the WH542×HD29 population, with both parents contributing the high-value alleles. A major locus (R2 = 27.8%) and seven minor loci (R2 = 4.4–15.8%) were detected in the WH542×W485 population. GWA mapping validated QTL regions in the bi-parent populations, but also identified novel loci not previously associated with Karnal bunt resistance. Meta-QTL analysis aligned the results from this study with those reported in wheat over the last two decades. Two major clusters were detected, the first on chromosome 4B, which clustered with Qkb.ksu-4B, QKb.cimmyt-4BL, Qkb.cim-4BL, and the second on chromosome 3B, which clustered with Qkb.cnl-3B, QKb.cimmyt-3BS and Qkb.cim-3BS1. The results provide definitive chromosomal assignments for QTL/genes controlling Karnal bunt resistance in common wheat, and will be useful in pre-emptive breeding against the pathogen in wheat-producing areas that are free of the disease.
Publication - Decomposing additive genetic variance revealed novel insights into trait evolution in synthetic hexaploid wheat(Frontiers, 2018) Jighly, A.; Joukhadar, R.; Singh, S.; Ogbonnaya, F.C.Whole genome duplication (WGD) is an evolutionary phenomenon, which causes significant changes to genomic structure and trait architecture. In recent years, a number of studies decomposed the additive genetic variance explained by different sets of variants. However, they investigated diploid populations only and none of the studies examined any polyploid organism. In this research, we extended the application of this approach to polyploids, to differentiate the additive variance explained by the three subgenomes and seven sets of homoeologous chromosomes in synthetic allohexaploid wheat (SHW) to gain a better understanding of trait evolution after WGD. Our SHW population was generated by crossing improved durum parents (Triticum turgidum; 2n = 4x = 28, AABB subgenomes) with the progenitor species Aegilops tauschii (syn Ae. squarrosa, T. tauschii; 2n = 2x = 14, DD subgenome). The population was phenotyped for 10 fungal/nematode resistance traits as well as two abiotic stresses. We showed that the wild D subgenome dominated the additive effect and this dominance affected the A more than the B subgenome. We provide evidence that this dominance was not inflated by population structure, relatedness among individuals or by longer linkage disequilibrium blocks observed in the D subgenome within the population used for this study. The cumulative size of the three homoeologs of the seven chromosomal groups showed a weak but significant positive correlation with their cumulative explained additive variance. Furthermore, an average of 69% for each chromosomal group's cumulative additive variance came from one homoeolog that had the highest explained variance within the group across all 12 traits. We hypothesize that structural and functional changes during diploidization may explain chromosomal group relations as allopolyploids keep balanced dosage for many genes. Our results contribute to a better understanding of trait evolution mechanisms in polyploidy, which will facilitate the effective utilization of wheat wild relatives in breeding.
Publication - Genome-wide association for grain morphology in synthetic hexaploid wheats using digital imaging analysis(licensee BioMed Central Ltd, 2014) Rasheed, A.; Xianchun Xia; Ogbonnaya, F.C.; Mahmood, T.; Zhang, Z.; Mujeeb-Kazi, A.; He ZhonghuGrain size and shape greatly influence grain weight which ultimately enhances grain yield in wheat. Digital imaging (DI) based phenomic characterization can capture the three dimensional variation in grain size and shape than has hitherto been possible. In this study, we report the results from using digital imaging of grain size and shape to understand the relationship among different components of this trait, their contribution to enhance grain weight, and to identify genomic regions (QTLs) controlling grain morphology using genome wide association mapping with high density diversity array technology (DArT) and allele-specific markers.
Publication - Identification of novel quantitative trait loci linked to crown rot resistance in spring wheat(MDPI, 2018) Erginbas Orakci, G.; Sehgal, D.; Sohail, Q.; Ogbonnaya, F.C.; Dreisigacker, S.; Pariyar, S.R.; Dababat, A.A.Crown rot (CR), caused by various Fusarium species, is a major disease in many cereal-growing regions worldwide. Fusarium culmorum is one of the most important species, which can cause significant yield losses in wheat. A set of 126 advanced International Maize and Wheat Improvement Center (CIMMYT) spring bread wheat lines were phenotyped against CR for field crown, greenhouse crown and stem, and growth room crown resistance scores. Of these, 107 lines were genotyped using Diversity Array Technology (DArT) markers to identify quantitative trait loci linked to CR resistance by genome-wide association study. Results of the population structure analysis grouped the accessions into three sub-groups. Genome wide linkage disequilibrium was large and declined on average within 20 cM (centi-Morgan) in the panel. General linear model (GLM), mixed linear model (MLM), and naïve models were tested for each CR score and the best model was selected based on quarantine-quarantine plots. Three marker-trait associations (MTAs) were identified linked to CR resistance; two of these on chromosome 3B were associated with field crown scores, each explaining 11.4% of the phenotypic variation and the third MTA on chromosome 2D was associated with greenhouse stem score and explained 11.6% of the phenotypic variation. Together, these newly identified loci provide opportunity for wheat breeders to exploit in enhancing CR resistance via marker-assisted selection or deployment in genomic selection in wheat breeding programs.
Publication - Association analysis of resistance to cereal cyst nematodes (Heterodera avenae) and root lesion nematodes (Pratylenchus neglectus and P. thornei) in CIMMYT advanced spring wheat lines for semi-arid conditions(Japanese Society of Breeding, 2016) Dababat, A.A.; Gomez-Becerra, H.F.; Erginbas Orakci, G.; Dreisigacker, S.; Imren, M.; Toktay, H.; Elekcioglu, I.H.; Tesfamariam Mekete; Nicol, J.M.; Ansari, O.; Ogbonnaya, F.C.To identify loci linked to nematode resistance genes, a total of 126 of CIMMYT advanced spring wheat lines adapted to semi-arid conditions were screened for resistance to Heterodera avenae, Pratylenchus neglectus, and P. thornei, of which 107 lines were genotyped with 1,310 DArT. Association of DArT markers with nematode response was analyzed using the general linear model. Results showed that 11 markers were associated with resistance to H. avenae (pathotype Ha21), 25 markers with resistance to P. neglectus, and 9 significant markers were identified to be linked with resistance to P. thornei. In this work we confirmed that chromosome 4A (~90–105 cM) can be a source of resistance to P. thornei as has been recently reported. Other significant markers were also identified on chromosomal regions where no resistant genes have been reported for both nematodes species. These novel QTL were mapped to chromosomes 5A, 6A, and 7A for H. avenae; on chromosomes 1A, 1B, 3A, 3B, 6B, 7AS, and 7D for P. neglectus; and on chromosomes 1D, 2A, and 5B for P. thornei and represent potentially new loci linked to resistance that may be useful for selecting parents and deploying resistance into elite germplasm adapted to regions where nematodes are causing problem.
Publication - Genetic diversity of Pyrenophora tritici-repentis in Algeria as revealed by amplified fragement length polymorphism (AFLP) analysis(Academic Journals, 2013) Benslimane, H.; Lababidi, S.; Yahyaoui, A.; Ogbonnaya, F.C.; Bouznad, Z.; Baum, M.Tan spot caused by Pyrenophora tritici-repentis is a major wheat disease. DNA of 61 isolates of P.$$tritici-repentis from different cereal growing areas in Algeria were analyzed using amplified fragment$$length polymorphism (AFLP) in order to study the genetic diversity among this population. Initially, 78$$primer combinations were tested, of which 12 were selected and applied to the 61 isolates. There was a$$high genetic diversity in this population of P. tritici-repentis with 61 different haplotypes among the 61$$isolates selected. The Jaccard similarity index range was 1.43 to 68.37%. Cluster analysis showed that,$$clustering of isolates was independent of their race classification, geographic origin, or host plant.$$However, one isolate (Ptr24) that showed a new virulence pattern in our previous race analysis study$$was clearly distinguished from the rest of the population studied. This isolate had not only new$$virulence but also different genetic makeup to other P. tritici-repentis isolates and requires additional$$studies to decipher complete knowledge of host-pathogen interactions for tan spot of wheat.
Publication - The screening of wheat germplasm for resistance to stripe and leaf rust in Kazakhstan using molecular markers(David Publishing, 2012) Kokhmetova, A.; Yessenbekova, G.; Morgounov, A.; Ogbonnaya, F.C.Resistance to stripe and leaf rusts is the most important objectives in Kazakhstan, and they are the major factor that adversely affects wheat yield and quality and finally causes considerable economic damage. This study was aimed at characterizing elite wheat germplasm from Central Asia using molecular markers linked to the Lr34/Yr18 dual rust resistance gene and to identify new wheat germplasm resistant to leaf and yellow rust. In experiment with germplasm developed from Kazakhstan and Central and West Asia yellow rust trap nursery (CIMMYT), the frequency of the csLV34b-allele linked to Lr34/Yr18 (150 bp) was low and only seven of the 42 accessions had allele diagnostic of Lr34/Yr18. Two genotypes had high level of resistance, showing immune reaction to all three rusts. Disease severity from resistance to moderate susceptible was recorded in the lines having Lr34/Yr18 genes, which is comparable to the disease severity observed on the cultivar, Cook (20MS-30MS), carrying Lr34/Yr18 genes. The molecular screening of a set of additional 51 wheat genotypes, including commercial cultivars and breeding lines from different countries, showed that the csLV34 marker was present in 20 genotypes. This allowed us to select lines that could be used for future breeding work. In all, a total of 269 lines possessed effective Lr34/Yr18 gene complex: 28 lines of F4 Almaly/Opata-85, 34 lines of Almaly/Super Kauz, 26 lines of F4 Parula/(Almaly/Anza), 23 lines of F4 Babax 1/Opata 85, and 27 lines of Madsen/Cook populations. This further validates and confirms that the STS marker csLV34 and morphological marker leaf tip necrosis are reliable in the identification of carriers of effective slow rusting Lr34/Yr18 gene. The germplasms identified are further being tested for end-used quality and could be released by NARS as varieties in the various countries of Central Asia.
Publication - Progress in host plant resistance in wheat to Russian wheat aphid (Hemiptera: Aphididae) in North Africa and West Asia(Southern Cross Publishing Group, 2011) Bouhssini, M. El; Ogbonnaya, F.C.; Ketata, H.; Mosaad, M.M.; Street, K.; Amri, A.; Keser, M.; Rajaram, S.; Morgounov, A.; Rihawi, F.; Dabus, A.; Smith, C.M.Russian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is an important pest of wheat and barley in several countries of North Africa and West Asia, e.g., Morocco, Algeria, Tunisia, Ethiopia, Yemen, Turkey and Iran. Host plant resistance is the most economical and practical means of controlling this insect. Field and greenhouse screening of introduced and local wheat germplasm at ICARDA resulted in the identification of several sources of resistance which were subsequently incorporated into ICARDA elite wheat germplasm and distributed as RWA gene pool to NARS (National Agricultural Research Systems) in affected countries. Crosses were initiated in 1998 to introgress resistance into winter/facultative bread wheat and the segregating populations were evaluated for RWA resistance and agronomic performance at the ICARDA Experiment Station at Tel Hadya. Selected advanced lines were sent to North African, and West Asian countries for evaluation of RWA and disease resistance and agronomic adaptation under local conditions. Additional identified sources of RWA resistance are now in use in the ICARDA wheat breeding program. Haplotype analysis using molecular markers previously identified as diagnostic for Dn resistance genes revealed that some recently identified resistance sources are unrelated to previously described Dn1-Dn9 genes, and may represent new genes for deployment in RWA breeding. These apparent novel resistance gene(s) could be effective against some of the more virulent biotypes and could be deployed in breeding programs to increase the diversity of available genetic resistances. The reaction of wheat differentials containing different Dn genes indicates that the Syrian RWA biotype is less virulent than US RWA2 biotype.
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