Identification and Deployment of QTL for Fusarium Head Blight Resistance in U.S. Hard Winter Wheat PDF Download

Author: Nosheen Fatima
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Languages : en
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Fusarium head blight (FHB) is one of the most damaging diseases in wheat, which impacts both grain yield and quality drastically. Recently, the disease has become more prevalent in the hard winter wheat (HWW) grown areas of the United States including Oklahoma where FHB has not been reported before. Growing resistant cultivars is the most economical and effective strategy for disease management. To dissect quantitative trait loci (QTL) for FHB resistance in a moderately resistant hard winter wheat (HWW) cultivar, Overland, a population of 186 recombinant inbred lines (RILs) was developed from the cross between Overland and Overley, a susceptible HWW cultivar from Kansas. The RILs were evaluated for FHB type II resistance in one field and three greenhouse experiments and genotyped using genotyping-by-sequencing (GBS) markers. Three FHB resistance QTLs were mapped on Chromosomes 4DL, 4AL, and 5BL. The QTL on 4DL was the most consistent one and explained up to 13% of the phenotypic variation for type II resistance and 14 % for low Fusarium damaged kernels (FDK). Two GBS markers closely linked to the 4DL QTL were successfully converted to Kbioscience competitive allelic specific PCR (KASP) assays and can be used in marker-assisted breeding. In breeding, a single QTL may provide only partial resistance and pyramiding of several resistance QTLs in a cultivar can provide more protection in FHB epidemics. Fhb1 is a major QTL for FHB resistance from a Chinese source and Fhb3 is an alien gene from wild rye grass (Leymus racemosus). To study the effects of these QTLs individually and cumulatively in hard winter wheat backgrounds, they were transferred into two HWW cultivars Overland and Jagger. The results show that Fhb1 significantly increased FHB resistance, but Fhb3 did not. Thus, Fhb3 is not an effective gene for improvement of FHB resistance in HWW.

Author: Marshall Clinesmith
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Languages : en
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Fusarium head blight (FHB) is a fungal disease, mostly commonly associated with F. graminearum, which affects cereal crops such as wheat resulting in substantial yield losses and reductions in grain quality. The onset of the disease can occur rapidly when warm, wet or humid weather coincides with flowering in the spring. The pathogen also produces mycotoxins such as deoxynivalenol (DON) that accumulate in the grain and can be toxic to humans and animals. This results in additional economic losses as contaminated grain must be discarded or blended to reduce the amount of toxin in order to meet federal regulatory limits. Development and deployment of resistant cultivars has proved to be an effective method to combat the disease, and many resistant sources have been reported in the literature with the majority of major resistance coming from Chinese landraces. Transferring resistance from these sources into cultivars adapted to the U.S. has been a slow process due to linkage of FHB resistance genes with poor agronomic traits. Therefore, it is important for breeders to search for sources of resistance in native material adapted to their local conditions. In this study, we aimed to identify quantitative trait loci (QTL) for resistance to spread of FHB within the head (Type II resistance), accumulation of DON toxin in grain (Type III resistance), and resistance to kernel infection (Type IV resistance). Plant material consisted of 148 doubled haploid (DH) lines from a cross between the two moderately resistant hard red winter wheat (HRWW) cultivars Art and Everest. The study was conducted for two years using a point inoculation technique in a greenhouse in Manhattan, KS. Three QTL conferring resistance to FHB traits were detected on chromosomes 2D, 4B, and 4D. The QTL on chromosomes 4B and 4D overlapped with the major height genes Rht1 and Rht2, respectively. Plant height has shown previous associations with FHB, though the underlying cause of these associations is not well understood. The majority of results have reported increased susceptibility associated with shorter plant types; however, in this study, the haplotype analysis for the Rht-B1 and Rht-D1 loci showed an association between the dwarfing alleles and increased resistance to FHB. This suggests either pleiotropic effects of these loci or perhaps linkage with nearby genes for FHB resistance. Markers close to the peaks of the FHB resistance QTL have the potential for Kompetitive Allele Specific PCR (KASP) marker development and subsequent use in marker assisted selection (MAS) to help improve overall FHB resistance within breeding programs.

Author: Abdulrahman Hashimi
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Languages : en
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Fusarium head blight (FHB) is one of the devastating wheat diseases worldwide. It reduces not only yield, but also grain quality due to mycotoxins produced by the pathogen Fusarium graminearum. To identify consistent quantitative trait loci (QTLs) for FHB resistance in two US winter wheat 'CI13227' and 'Lyman', we genotyped a double haploid (DH) population from '' x 'CI13227' X 'Lakin' using Illumina wheat 90K single nucleotide polymorphism (SNP) chips and two recombinant inbred line (RIL) populations from 'Lyman'x 'Overley' and 'Lyman'x 'CI13227' using genotyping-by-sequencing (GBS) and evaluated the three populations for FHB type II resistance in greenhouse and field experiments. QTL mapping identified four QTLs on chromosomes 4BS, 5AL, 2DS and 7A in the 'CI13227' x 'Lakin' population, which explained 8-17% of the phenotypic variation in different experiments. The QTL on 4BS from CI13227 showed the largest effect among QTLs detected in the 'CI13227' x 'Lakin' population and were consistently detected in three experiments. 'CI13227' contributed the resistance alleles at QTLs on 2DS and 7A, whereas 'Lakin' contributed the resistance allele at 5AL QTL. The 7A QTL was detected in only one experiment. The QTLs on the chromosomes 4B and 2D showed a high correlation with plant height, suggesting a linked genes or pleiotropic effect of these QTLs. In the 'Lyman'/'Overley' population, six QTLs were located on the chromosomes 1A, 2A, 3A, 1B, 2B and 4B, and explained 5.5 -21% of the phenotypic variations for type II resistance. The QTL on 3A from 'Lyman' showed the largest effects and detected in two greenhouses experiments. Significant correlation was not detected between the PSS and plant height in this population. In the 'Lyman'/'CI13227' population, four QTLs were detected with two QTLs on chromosomes 1A and 7A from 'CI13227' and chromosomes 2B and 3A from 'Lyman' and QTLs on 7A from 'CI13227' and 2B and 3A from 'Lyman' confirmed the results from the previous two populations. Markers for the repeatable QTLs were converted into Kompetitive allele specific PCR (KASP) markers for marker-assisted breeding to pyramid these QTLs in U.S. winter wheat.

Author: Jin Cai
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Category :
Languages : en
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Fusarium head blight (FHB) is a devastating fungal disease in wheat, reducing not only grain yield but also quality. The pathogen produces the mycotoxin deoxynivalenol (DON) that induces severe toxicological problems in human and animals. Using host resistance has been the most efficient way to control the disease. To identify quantitative trait loci (QTLs) for FHB resistance in Chinese landrace Haiyanzhong (HYZ), a recombinant inbred lines (RILs) population derived from a cross between HYZ and Wheaton was developed. The RILs were evaluated for percentage of symptomatic spikelets (PSS) in three greenhouse experiments, and genotyped using simple sequence repeats (SSRs) and single nucleotide polymorphism (SNPs) developed from genotyping-by-sequencing (GBS). Eight QTLs were identified for type II (PSS) resistance on chromosomes 5A, 6B, 7D, 2B (2), 3B, 4B, and 4D, with 5A as the major QTL. Ten SNPs closely linked to 5A, 6B, and 2B QTLs were successfully converted to Kompetitave allelic specific PCR (KASP) assays. To identify common QTLs across different populations, we constructed high-density GBS-SNP maps in an additional four RIL populations derived from the Chinese landraces, Wangshuibai (WSB), Baishanyuehuang (BSYH), Huangfangzhu (HFZ), and Huangchandou (HCD) and conducted meta-analysis of the QTLs for FHB resistance using a consensus map developed from the five populations. We identified six MQTLs on chromosomes 3BS (2), 3A, 3D, 2D, and 4D and 23 tightly linked GBS-SNPs to the MQTLs. These GBS-SNPs were successfully converted to KASPs. The KASPs linked to MQTLs can be used for pyramiding these QTL in breeding programs. To quickly reduce FHB damage in U.S. hard winter wheat (HWW), we transferred Fhb1, a major QTL with stable effects on FHB resistance, from Ning7840 into three adapted HWW cultivars Overland, Jagger, and Overley, by marker-assisted backcross (MAB), and assessed the effect of Fhb1 on FHB resistance in these different backgrounds. The results showed that Fhb1 can significantly lower FHB severity, Fusarium-damaged kernel (FDK), and DON accumulation in the all the three HWW backgrounds. Some of the selected lines showed high levels of FHB resistance, but agronomically similar traits as recurrent parents, can be used as resistant parents to improve HWW FHB resistance.

Author: Umara Sahar Rana
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Languages : en
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Fusarium head blight (FHB), also known as 'scab', incited by Fusarium graminearum (Schw), is one of the most damaging fungal diseases in wheat. FHB reduces grain yield drastically, but also grain quality due to shriveled kernels, protein damage, and mycotoxin contamination caused by the fungal infection. Host plant resistance is the most effective and environmentally safe approach to combat this disease. To identify resistance genes from locally adapted cultivars, a population of 178 recombinant inbred lines (RILs) from Overland × Everest was genotyped using single nucleotide polymorphism (SNP) markers derived from genotyping-by-sequencing (GBS). The RIL population was phenotyped for resistance to the initial infection (type I), fungal spread within a spike (type II), mycotoxin (DON) accumulation in grains (type III) and Fusarium damaged kernel (type IV) in repeated greenhouse and field experiments. Seven QTLs were identified on chromosome arms 1AL, 3BL, 4BS, 4BL, 6AL, 6BL 7AS and 7BL for type I resistance. Hard winter wheat cultivar Everest contributes all the resistance alleles except two on chromosome arms 4BS and 6BL, which are contributed by hard winter wheat cultivar Overland. Six QTLs on chromosome regions of 1BL, 4A, 4BS, 5AL, 6BL and 7AS confer type II resistance with the resistance QTLs on 1BL, 4BS, 6BL and 7AS from Everest and on 4A, 4BS, and 5AL from Overland. The type II QTL on chromosome 4BS is overlapped with the reduced height gene Rht-B1. QTLs for type III resistance were mapped on 4BS and 5AL while QTLs for type IV resistance were mapped on chromosome 4BS, 5AL and 7AS and they overlapped with type II resistance in the corresponding chromosome regions. The haplotype analysis showed that genotypes containing multiple QTLs showed significantly higher resistance than those with fewer or no QTLs, indicating that these QTLs have additive effects on FHB resistance. Type I FHB resistance was poorly characterized in the literature. The current study demonstrated that Everest carries several QTLs for type I resistance, thus is a useful native source for type I resistance. Some SNP markers tightly linked with the QTLs for different types of resistance were successfully converted into Kompetitive allele-specific polymerase chain reaction (KASP) assays and could be used in marker-assisted breeding for FHB resistance in wheat.

Author: Jin Cai
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Category :
Languages : en
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Fusarium head blight (FHB) is one of the most devastative diseases in wheat. Growing resistant cultivars is one of the most effective strategies to minimize the disease damage. Huangcandou (HCD) is a Chinese wheat landrace showing a high level of resistance to FHB spread within a spike (type II). To identify quantitative traits loci (QTL) for resistance in HCD, a population of 190 recombinant inbred lines (RILs) were developed from a cross between HCD and Jagger, a susceptible hard winter wheat (HWW) released in Kansas. The population was evaluated for type II resistance at the greenhouses of Kansas State University. After initial marker screening, 261 polymorphic simple-sequence repeats (SSR) between parents were used for analysis of the RIL population. Among three QTL identified, two from HCD were mapped on the short arms of chromosomes 3B (3BS) and 3A (3AS). The QTL on the distal end of 3BS showed a major effect on type II resistance in all three experiments. This QTL coincides with a previously reported Fhb1, and explained 28.3% of phenotypic variation. The QTL on 3AS explained 9.7% of phenotypic variation for mean PSS over three experiments. The third QTL from chromosome 2D of Jagger explained 6.5% of phenotypic variation. Allelic substitution using the closest marker to each QTL revealed that substitution of Jagger alleles of two QTL on 3AS and 3BS with those from HCD significantly reduced the PSS. HCD containing both QTL on 3AS and 3BS with a large effect on type II resistance can be an alternative source of FHB resistance for improving FHB type II resistance in wheat. Besides, meta-analyses were used to estimate 95% confidence intervals (CIs) of 24 mapped QTL in five previously mapped populations derived from Chinese landraces: Wangshuibai (WSB), Haiyanzhong (HYZ), Huangfangzhu (HFZ), Baishanyuehuang (BSYH) and Huangcandou (HCD). Nineteen QTL for FHB type II resistance were projected to 10 QTL clusters. Five QTL on chromosomes 1A, 5A, 7A, and 3BS (2) were identified as confirmed QTL that have stable and consistent effects on FHB resistance and markers in these meta-QTL regions should be useful for marker-assisted breeding.

Author: Janet M. Lewis
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Category : Fusarium diseases of plants
Languages : en
Pages : 352

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Author: Harwinder Sidhu
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Languages : en
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Fusarium Head Blight (FHB) is a devastating disease of Wheat (Triticum aestivum L.) caused primarily by Fusarium graminearum Schwabe in Canada. Wheat FHB results in yield and produce quality losses. The clearest symptoms of FHB are premature bleaching of spikelets in the field, and fusarium damaged kernels in the harvested seed. Insufficient and costly disease control strategies make breeding for FHB resistance in wheat an ideal choice. There is a lack of FHB resistance sources in the Canadian wheat germplasm and Genome Wide Association Studies (GWAS) can be utilized to identify such sources. Furthermore, as no Quantitative Trait Loci (QTL) provides absolute resistance to FHB, identification of novel sources of resistance is desired. Genomic Selection (GS) has great potential in crop improvement, specifically for quantitative traits. A diversity panel that represents the genetic diversity of the Canadian, i.e., high latitude North American winter wheat was assembled for this thesis and the genetic diversity, population structure, and linkage disequilibrium of the germplasm was studied. To identify QTL associated with FHB, a GWAS study was conducted using the phenotypic data collected at three locations over two years. For understanding the role of number of genotypic markers, population structure, and choice of model in trait prediction modelling, a GS study was conducted. The Canadian Winter Wheat Diversity Panel is a diverse collection of winter wheat capturing diversity both in time and geography from Canada. The panel comprises of seven subpopulations with different LD, allele frequencies, and genetic diversity parameters. Multiple QTL associated with FHB related traits were identified on 13 chromosomes which may harbor genes involved in plant defense and stress response mechanisms. For FHB resistance improvement, the GS study demonstrated that the modelling parameters can be determined based upon the genotypic information available. Deoxynivalenol contamination was one of the traits with the highest prediction accuracy. GS can account for minor effect QTL, which is beneficial when breeding for quantitative traits. FHB resistant varieties are needed for an effective and economical disease control strategy in wheat and GS can complement current breeding efforts to develop FHB resistant wheat varieties.

Author: Santosh Nayak
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ISBN:
Category : Wheat
Languages : en
Pages : 152

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Fusarium head blight (FHB) is one of the most destructive diseases of wheat causing significant yield losses and quality reduction in the humid areas of the world. It is also an emerging wheat disease in Southeastern Idaho of the United States. Resistance to FHB is known to be a quantitatively inherited trait and highly influenced by confounding environmental factors. The objectives of this study were to map and characterize QTL associated with FHB resistance in 151 (F44:6 ) recombinant inbred lines (RILs) derived from the cross between a resistant cultivar 'UI Stone' and a moderately susceptible cultivar 'Alturas' The population was evaluated for type II FHB resistance by measuring disease severity expressed as a percentage of infected spikelets (PIS) in four greenhouse experiments over three years. Two major QTL for type II FHB resistance, QFhbuis.ab-2B and QFhbuis.ab-3B , were identified by both single marker and composite interval mapping (CIM) methods and together these QTL explained 23.6 to 24.8% of phenotypic variation. Four additional QTL, QFhbuis.ab-1D, QFhbuis.ab-2D·1, QFhbuis.ab-2D·2 , and QFhbalt.ab-4A , were identified by either the single marker or CIM methods and were associated with disease severity in specific experiments. The two major QTL identified in this study have potential application in marker-assisted breeding of FHB resistance. This study also identified 4 lines with better FHB resistance and higher grain yield than 'UI Stone' and these could be used as germplasm and/or released as new resistant cultivars after further testing.

Author: Sunil Kumar
Publisher:
ISBN:
Category : Wheat fusarium culmorum head blight
Languages : en
Pages : 158

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