Fusarium-damaged Kernels Research Articles

Digital Image Analysis Method for Estimation of Fusarium‐Damaged Kernels in Wheat

ABSTRACTFusarium head blight (FHB) of wheat (Triticum aestivum L.), or head scab, causes a reduction in grain yield and quality through the formation of shriveled, dull‐grey seeds called “tombstones” or Fusarium‐damaged kernels (FDK). Fusarium‐damaged kernels are commonly quantified on a percentage basis by visually separating damaged from healthy kernels following harvest, in a process that is both time consuming and labor intensive. The objective of this study was to evaluate an alternative method for quantifying FDK through the use of the digital image analysis program ImageJ. The ‘NC‐Neuse’ × ‘AGS 2000’ F5–derived recombinant inbred population of 172 lines and the NC‐Neuse בBess’ double haploid population of 112 lines were used in this study. NC‐Neuse and Bess were moderately resistant and AGS 2000 was susceptible to FHB. The populations were evaluated under moderate to heavy FHB epidemics in a total of five environments in North Carolina, Maryland, and Missouri with two to three replications per environment during the 2010 to 2011 and 2011 to 2012 seasons. Following hand harvest and grain processing, FDK was estimated by (i) visual separation of diseased kernels and (ii) digital image analysis using ImageJ on captured images of grain samples. The correlation between the two methods ranged from 0.72 to 0.80 over five environments. A lower correlation was observed in one environment due to cracked and broken kernels in the samples. Digital image analysis was three times faster than the visual method and estimated FDK on a larger scale per plot sample, whereas labor and time constraints limited the sample size for the visual method. Digital image analysis was consistent over samples and appears well suited as an alternative form to estimate percent of FDK in grain that is not damaged in other ways.

Erratum to: Differential influence of QTL linked to Fusarium head blight, Fusarium-damaged kernel, deoxynivalenol contents and associated morphological traits in a Frontana-derived wheat population

Erratum to: Differential influence of QTL linked to Fusarium head blight, Fusarium-damaged kernel, deoxynivalenol contents and associated morphological traits in a Frontana-derived wheat population

Field evaluation of resistance to kernel infection and mycotoxin accumulation caused by Fusarium head blight in western Japanese wheat (Triticum aestivum L.) cultivars

Fusarium head blight (FHB) remains a serious problem that causes yield and grain quality losses, and mycotoxin accumulation in wheat production in western Japan. A 3-year field trial with artificial FHB inoculation was conducted to evaluate varietal characteristics of FHB resistance among 31 wheat cultivars/lines cultivated in western Japan, including one standard line. Severity of FHB, frequency of Fusarium-damaged kernels (FDK), deoxynivalenol concentration (DON), nivalenol concentration (NIV), and grain yield showed significant differences among years and among cultivars/lines. Interaction between years and cultivars/lines was also significant in these traits, but F values were larger for cultivars/lines than for the interaction. Correlation analysis showed that cultivars/lines with lower FHB severities tended to have lower FDK, DON and NIV, and a higher yield. Resistance to kernel infection (RKI), residuals calculated by regressing FDK against FHB severity, and resistance to mycotoxin accumulation (RTA), residuals calculated by regressing DON + NIV against FDK, also differed significantly among cultivars/lines. These results indicated that varietal differences in response to FHB symptom development, RKI and RTA exist among wheat cultivars/lines in western Japan. Such information is important to aid producers in controlling the disease and for breeders to improve FHB resistance and reduce mycotoxin accumulation in commercial wheat cultivars.

Differential influence of QTL linked to Fusarium head blight, Fusarium-damaged kernel, deoxynivalenol contents and associated morphological traits in a Frontana-derived wheat population

The genetic background of Fusarium head blight (FHB) resistance in the moderately resistant wheat variety Frontana was investigated in the GK Mini Mano/Frontana DH population (n = 168). The plant material was evaluated across seven epidemic environments for FHB, Fusarium-damaged kernel (FDK) and deoxynivalenol (DON) contents caused by two Fusarium species (F. culmorum and F. graminearum). The effects of phenotypic traits such as plant height and heading date were also considered in the experiments. In the population, 527 polymorph markers (DArT, SSR) within a distance of 1,381 cM distance were mapped. The quantitative trait locus/loci (QTL) on chromosomes 4A and 4B demonstrated a significant linkage only with FHB, while QTL on chromosomes 3A, 4B, 7A and 7B were linked to DON accumulation alone. Regions determining all the investigated Fusarium resistance traits were identified on chromosomes 1B, 2D, 3B, 5A, 5B and 6B. The markers in these regions are of the greatest significance from the aspect of resistance breeding. Our results indicate that the genetic background of resistance against FHB, FDK and DON accumulation can differ, and all these traits should be taken under consideration during resistance tests. Moreover, this is the first report on the mapping of Frontana-derived QTL that influence DON accumulation, which is important since the level of DON contamination determines the actions of the food and feed industries. Selection should therefore also focus on this trait by using molecular markers linked to DON content.

Fusarium-Damaged Kernels and Deoxynivalenol in Fusarium-Infected U.S. Winter Wheat

Fusarium head blight (FHB) is a devastating disease that threatens wheat (Triticum aestivum) production in many areas worldwide. FHB infection results in Fusarium-damaged kernels (FDK) and deoxynivalenol (DON) that dramatically reduce grain yield and quality. More effective and accurate disease evaluation methods are imperative for successful identification of FHB-resistant sources and selection of resistant cultivars. To determine the relationships among different types of resistance, 363 (74 soft and 289 hard) U.S. winter wheat accessions were repeatedly evaluated for FDK and DON concentration in greenhouse and field experiments. Single-kernel near-infrared (SKNIR)-estimated FDK and DON were compared with visually estimated FDK and gas chromatography-mass spectroscopy-estimated DON. Significant correlations were detected between percentage of symptomatic spikelets and visual FDK in the greenhouse and field, although correlations were slightly lower in the field. High correlation coefficients also were observed between visually scored FDK and SKNIR-estimated FDK (0.72, P < 0.001) and SKNIR-estimated DON (0.68, P < 0.001); therefore, both visual scoring and SKNIR methods are useful for estimating FDK and DON in breeding programs.

Concentration and cultivar effects on efficacy of CLO-1 biofungicide in controlling Fusarium head blight of wheat

Fusarium head blight (FHB) is a destructive disease of wheat in Canada and Clonostachys rosea strain ACM941 has been identified as a promising biological control agent for managing FHB. In the present research the concentration and cultivar effects on the efficacy of CLO-1, a formulated product of C. rosea strain ACM941, in controlling FHB and deoxynivalenol (DON) contamination in wheat was studied. Of the eight concentrations ranging from 104 to 108cfumL−1 evaluated, significant effects were generally observed for concentrations at or above 106cfumL−1 in the greenhouse and field trials in 2009 and 2010. In the greenhouse, CLO-1 reduced the area under the disease progress curve (AUDPC) by 65–83%, Fusarium damaged kernels (FDK) by 68–92%, and DON by 51–95%. Under field conditions, CLO-1 reduced FHB index by 30–46%, FDK by 31–39%, and DON by 22–33%. These effects were numerically lower but not significantly different from those of the registered fungicide Folicur® (tebuconazole) used in these trials. When applied onto wheat cultivars differing in resistance to FHB in field trials in 2009 and 2010, CLO-1 was most effective on the moderately resistant cultivar AC Nass (representing the highest level of resistance commercially available) and least effective on the highly susceptible cultivar AC Foremost. Results of this study suggest that CLO-1 is a promising biocontrol product that may be used in combination with cultivar resistance for managing FHB in wheat.

Agressividade diferencial de espécies do complexo Fusarium graminearum em interação com o fungicida tebuconazole na redução do rendimento de trigo

No Brasil, a giberela em trigo é causada por espécies do complexo Fusarium graminearum, especialmente F. graminearum sensu stricto (Fgss) e F. meridionale (Fmer), as quais variam quanto ao potencial toxigênico. O objetivo deste trabalho foi avaliar a relação entre características fenotípicas e agressividade dessas duas espécies associadas ao uso do fungicida tebuconazole, da classe dos triazóis, com a redução de rendimento do trigo. Em dez isolados Fgss e nove Fmer, foram avaliados: esporulação total, taxa de germinação e sensibilidade ao fungicida tebuconazole. A inoculação, para cada isolado, foi feita por aspersão em espigas e as variáveis severidade da doença, incidência de grãos giberelados e o peso de grãos foram avaliados. O efeito de tebuconazole na redução da doença foi avaliado em ação protetora, seguida de inoculação na espigueta central de plantas da cultivar 'BRS Guamirim', com os seguintes tipos de inóculo: somente Fgss, somente Fmer ou a mistura de ambos (1:1). Isolados Fgss apresentaram maior esporulação total, maior taxa de germinação e foram menos sensíveis ao tebuconazole em comparação a Fmer. Grãos giberelados por isolados Fmer apresentaram 50% maior peso do que aqueles provenientes de inoculações com Fgss. O tebuconazole apresentou efeito fungistático e os grãos de espigas tratadas com o fungicida apresentaram peso 25% superior aos não tratados. Sugere-se que diferenças no potencial de dano aos grãos pelas duas espécies, assim como o efeito fungistático de triazóis, podem ajudar a explicar a co-ocorrência de diferentes micotoxinas, o que ainda necessita ser confirmado com dados de campo.

Molecular characterization of field resistance to Fusarium head blight in two US soft red winter wheat cultivars

In the soft red winter wheat (Triticum aestivum L.) regions of the US, Fusarium head blight (FHB, caused by Fusarium spp.) resistance derived from locally adapted germplasm has been used predominantly. Two soft red winter wheat cultivars, Massey and Ernie, have moderate resistance to FHB. Mapping populations derived from Becker/Massey (B/M) and Ernie/MO 94-317 (E/MO) were evaluated for FHB resistance and other traits in multiple environments. Eight QTL in B/M and five QTL in E/MO were associated with FHB variables including incidence, severity (SEV), index (IND), Fusarium damaged kernels (FDK), deoxynivalenol (DON), and morphological traits flowering time and plant height. Four QTL were common to both populations. Three of them were located at or near known genes: Ppd-D1 on chromosome 2DS, Rht-B1 on 4BS, and Rht-D1 on 4DS. Alleles for dwarf plant height (Rht-B1b and Rht-D1b) and photoperiod insensitivity (Ppd-D1a) had pleiotropic effects in reducing height and increasing FHB susceptibility. The other QTL detected for FHB variables were on 3BL in both populations, 1AS, 1DS, 2BL, and 4DL in B/M, and 5AL (B1) and 6AL in E/MO. The additive effects of FHB variables ranged from 0.4 mg kg−1 of DON to 6.2 % for greenhouse (GH) SEV in B/M and ranged from 0.3 mg kg−1 of DON to 8.3 % for GH SEV in E/MO. The 4DS QTL had epistasis with Ppd-D1, Qdon.umc-6AL, and Qht.umc-4BS, and additive × additive × environment interactions with the 4BS QTL for SEV, IND, and FDK in E/MO. Marker-assisted selection might be used to enhance FHB resistance through selection of favorable alleles of significant QTL, taking into account genotypes at Rht-B1b, Rht-D1a and Ppd-D1a.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-013-2149-y) contains supplementary material, which is available to authorized users.

Fusarium Damage in Small Cereal Grains from Western Canada. 2. Occurrence of Fusarium Toxins and Their Source Organisms in Durum Wheat Harvested in 2010

Samples of Canadian western amber durum harvested in 2010 were obtained as part of the Canadian Grain Commission Harvest Sample Program, inspected, and graded according to Canadian guidelines. A subset of Fusarium -damaged samples were analyzed for Fusarium species as well as mycotoxins associated with these species, including deoxynivalenol and other trichothecenes, moniliformin, enniatins, and beauvericin. Overall, Fusarium avenaceum and F. graminearum were the top two most frequently recovered species. Phaeosphaeria nodorum (a.k.a. Septoria nodorum ), F. culmorum , F. poae , F. acuminatum , and F. sporotrichioides were observed in samples as well. All samples analyzed for mycotoxins contained quantifiable concentrations of enniatins, whereas beauvericin, deoxynivalenol, and moniliformin were measured in approximately 75% of the samples. Concentrations in Fusarium -damaged samples ranged from 0.011 to 34.2 mg/kg of enniatins plus beauvericin, up to 4.7 mg/kg of deoxynivalenol, and up to 6.36 mg/kg of moniliformin. Comparisons of enniatins, beauvericin, and moniliformin concentrations to the occurrence of various Fusarium species suggest the existence of an infection threshold above which these emerging mycotoxins are present at higher concentrations. The current grading factor of Fusarium -damaged kernels manages concentrations of these emerging mycotoxins in grain; lower provisional grades were assigned to samples that contained the highest concentrations of enniatins, beauvericin, and moniliformin.

Fusarium Damage in Cereal Grains from Western Canada. 1. Phylogenetic Analysis of Moniliformin-Producing Fusarium Species and Their Natural Occurrence in Mycotoxin-Contaminated Wheat, Oats, and Rye

Harvest samples of common wheat (Triticum aestivum), oats (Avena sativa), and rye (Secale cereale) from producers in western Canada were analyzed for fungal infection by toxigenic Fusarium species and contamination by trichothecenes and moniliformin (MON). Fusarium graminearum and F. avenaceum were the two most frequently isolated species from samples of rye and wheat collected in 2010. F. poae and F. sporotrichioides were more commonly detected in randomly selected oat seeds. Other toxigenic Fusarium species including F. acuminatum, F. culmorum, and F. pseudograminearum as well as Phaeosphaeria nodorum (a.k.a. Septoria nodorum) were recovered primarily from fusarium-damaged kernels of wheat. Pure cultures of F. avenaceum, F. acuminatum, and other related species known to produce moniliformin were isolated from incubated seeds based on micro- and macromorphological criteria. The phylogenetic analysis inferred from partial DNA sequences of the acl1 and tef-1α genes revealed two major clades representing F. avenaceum and F. acuminatum, respectively. These clades comprised all Canadian isolates of the two species and a number of reference cultures studied earlier for their propensity to form moniliformin in vitro and in planta. However, some reference cultures previously reported to produce significant amounts of moniliformin formed minor phylogenetic lineages that represent rather distinct but closely related species. Concomitantly, cereal samples were analyzed for the presence of deoxynivalenol and moniliformin. These two Fusarium toxins were observed most frequently in common wheat, at concentrations up to 1.1 and 4.0 mg/kg, respectively. There was no apparent relationship between moniliformin concentrations and detection of F. avenaceum and F. acuminatum in rye and oat samples. Geographical analysis of the distribution of moniliformin and F. avenaceum and F. acuminatum across the Canadian Prairies also did not indicate a strong relationship.

Identification ofFusarium graminearuminfection severity of wheat grains by digitally aided spectroscopy

The Fusarium head blight caused mostly by Fusarium graminearum (F.g.) is the most important disease of wheat because it not only leads to yield loss, but the toxin contamination makes the yield harvested. First, visual assessment of the heads was made, then the ratio of Fusarium damaged kernels (FDK) becomes the attention, and since introduction of the toxin limits for wheat, the deoxynivalenol contamination has gained significance. However, the FDK has a greater practical significance, as the identification of Fusarium damaged kernels is the precondition of their separation.For this reason a more exact and more sensitive method was developed by using updated spectroscopy methods. The infection sensitive spectral index (ISSI) function has been developed to characterize spectral features of images of grains with different infection severities. The green and red color ranges could be best used in this analysis. It was also found that the way how different spectra from different grains or samples can be normalized and compared. This histogram analyzing method uses scanned images and it seems to be useful in describing the infection severity of heterogeneous samples better than available before.This might serve as scientific background to develop new instruments for rapid tests.

Fusarium graminearumInfection and Deoxynivalenol Concentrations During Development of Wheat Spikes

Fusarium head blight (FHB) affects whole spikes of small grain plants, yet little is known about how FHB develops following infection, or about the concentration or progression of the mycotoxin deoxynivalenol (DON) in non-grain spike tissues. Fusarium mycotoxin levels in whole small-grain spikes are of concern to producers of whole-crop silage, as well as users of straw containing chaff for animal bedding or winter livestock rations. A 2-year field experiment was performed in Kinston, NC to reveal the time course of FHB development. Eight winter wheat cultivars with varying levels of FHB resistance were used in the 2006 experiment, and four of them were used in 2007. Plots were spray-inoculated with Fusarium graminearum macroconidia at mid-anthesis. Four durations of post-anthesis mist were applied: 0, 10, 20, or 30 days. Spike samples were collected and bulked by plot at 15, 25, 35, 45, 55, and 65 days after anthesis (daa); samples were separated into grain, glume, and rachis fractions. Increasing durations of post-anthesis moisture elevated grain DON and reduced the effect of cultivar on DON, presumably by affecting the expression of resistance, in all spike tissues. Fusarium-damaged kernels increased from early kernel-hard to harvest-ripe in both years. Percent infected kernels increased from medium-milk to harvest-ripe. During grainfill, DON concentrations declined in grain but increased in rachises and glumes, peaking at early kernel-hard, before declining. Higher mean and maximum DON levels were observed in rachises and glumes than in grain. Estimated whole-spike DON peaked at early kernel-hard. In a high-FHB year, whole-plant harvest for forage should be conducted as early as possible. Straw that may be consumed by livestock could contain significant amounts of DON in chaff, and DON can be minimized if straw is sourced from low-symptom crops. Cultivar FHB resistance ratings and disease data should be useful in predicting whole-spike DON levels. Overall, associations between grain DON levels in harvest-ripe and prior samples were stronger the later the prior samples were collected, suggesting limits to the possibility of predicting harvest-ripe grain DON from earlier levels.

Single and sequential applications of metconazole alone or in mixture with pyraclostrobin to improve Fusarium head blight control and wheat yield in Brazil

Four fungicide trials were conducted in northern RS state during 2009. Six treatments, from the combination of one (flowering = F) or two applications (F + 10 days) of metconazole sprayed alone or in mixture with pyraclostrobin were tested. Fusarium head blight incidence (INC) and severity (SEV) were assessed at the pre-harvest period and Fusarium-damaged kernel (FDK), kernel infection (KI) and deoxynivalenol (DON) and nivalenol (NIV) trichothecenes were quantified on harvested kernels. Disease incidence ranged from 43.8% to 90% and from 7.3% to 31% respectively in the unsprayed check. Both INC and SEV were reduced in all fungicide treatments compared to the check across trials. Levels of FDK and KI were not affected by fungicides where susceptible and moderately resistant cultivars were used, respectively. The fungicide x cultivar susceptibility interaction was significant with the highest severity reduction (>70%) susceptible cultivars. Overall yield increased (+400 kg/ha) in fungicide-treated plots compared to the check; the mixture of fungicides led to higher increase (+275kg/ha) in yield. Yield increased modestly (+150 kg/ha) for two sprays compared to a single spray. Both DON and NIV were found in variable levels across trials but non significant effect of fungicides was found on mycotoxin levels.

Evaluation of different fungicides for control of fusarium head blight in wheat inoculated with 3ADON and 15ADON chemotypes of Fusarium graminearum in Canada

Fusarium head blight (FHB) continues to threaten the economic sustainability of many small grain producers in Manitoba by causing losses in grain yield and quality. In this 2-year study, four fungicides were tested on two spring wheat cultivars with different levels of resistance to FHB inoculated with 3ADON and 15ADON chemotypes of Fusarium graminearum. All fungicides (prothioconazole, tebuconazole, metconazole and prothioconazole+ tebuconazole) reduced FHB index, per cent Fusarium-damaged kernels (% FDK) and deoxynivalenol (DON) levels and increased yield compared with the non-sprayed control in the moderately resistant cultivar ‘Glenn’. In the highly susceptible cultivar ‘Roblin’, all fungicides reduced FHB index and increased yield compared with the non-sprayed control; however, inconsistent results were observed for FDK and DON. Differences were observed between the two chemotypes for all variables in both years except for FDK and yield in 2010. This study confirmed that host resistance plays an important role in host–pathogen–fungicide interaction. Therefore, the combined effect of growing moderately resistant cultivars with fungicide application can reduce damage caused by FHB even under high FHB severity.

CROP MANAGEMENT EFFECTS ON FUSARIUM HEAD BLIGHT, FUSARIUM-DAMAGED KERNELS AND DEOXYNIVALENOL CONCENTRATION OF SPRING WHEAT

Proper crop management is an important strategy in reducing Fusarium head blight (FHB) and deoxynivalenol (DON) concentrations in spring wheat (Triticum aestivum). A field study was conducted for three growing seasons to investigate FHB severity, Fusarium-damaged kernels (FDK), and DON concentrations and their inter-relationships as affected by planting and harvesting dates and nitrogen application. Cultivar ‘AC Brio’ was planted on three dates at approximately 10-d intervals starting from the last week of April. Five nitrogen (N) treatments were 0, 60 and 100 kg N ha−1 applied as starter, 60 (starter) + 40 kg N ha−1 as top-dress and 60 + 40 kg N ha−1 foliar spray at boot stage. Later planting increased FDK and DON concentration and the effects were greater in coarse-textured than in a fine-textured soil. DON concentration sometimes doubled when harvest was delayed after physiological maturity. Nitrogen treatments per se had no effects on FDK and DON.

Minor Differences in Anther Extrusion Affect Resistance to Fusarium Head Blight in Wheat

AbstractFusarium head blight (FHB) remains a serious problem due to yield loss and mycotoxin accumulation in wheat production worldwide. We previously reported that the closed‐flowering (no anther extrusion) characteristic was effective for increasing resistance to FHB infection. In this study, we investigated the relationships between the degree of anther extrusion (AE) and FHB damage using double haploid lines (DHLs), derived from F1 plants from crosses between closed‐flowering and opened‐flowering varieties. These DHLs exhibited various degrees of AE, and the degree of AE was significantly different among DHLs, regardless of the year and environment (pot‐ or field‐grown). FHB severity was the lowest in closed‐flowering DHLs, and DHLs with partially extruded anthers showed significantly higher FHB symptoms than those with closed‐flowering phenotypes. In general, DHLs with partially extruded anthers also had relatively severe FHB symptoms compared with those exhibiting full anther extrusion. FHB severity was significantly correlated with Fusarium‐damaged kernels and deoxynivalenol concentration. The results of this study showed that partially extruded anthers were considered to be a source of FHB infection. The closed‐flowering phenotype improved resistance to FHB infection. Meanwhile, phenotypes with rapid anther extrusion and ejection also could contribute to the avoidance of FHB infection.

β-D-glucan content of wheat kernels after inoculation With Fusarium culmorum Sacc

Winter wheat landraces and modern Slovak cultivars were inoculated with the pathogen Fusarium culmorum Sacc. by spraying in May 2008, in plot experiments under natural conditions in Piešťany, Slovakia. The objective was to examine the responses of the tested genotypes to inoculation with F. culmorum and to determine changes in the β-D-glucan content in the kernels. The area under the disease progress curve (AUDPC), Fusarium-damaged kernels (FDK) and the β-D-glucan and deoxynivalenol (DON) contents in the grains were determined using Megazyme and Ridascreen® Fast DON assay kits. Wheat landraces had lower AUDPC and FDK, and accumulated 67.4% less DON than modern cultivars. There were highly significant correlations (P &lt; 0.01) between AUDPC and DON content, between FDK and DON, and between AUDPC and FDK. The correlation between β-D-glucan content and AUDPC was also significant (P &lt; 0.05), but not correlations between β-D-glucan and other traits. The β-D-glucan content in the grain of wheat genotypes artificially inoculated with F. culmorum was lower than in grains without infection. The wheat landraces contained more β-D-glucan than modern cultivars and showed higher resistance to F. culmorum. The three wheat landraces had significantly lower spike and kernel infection compared to modern cultivars and could be used to breed elite cultivars with enhanced Fusarium head blight resistance.

Detection of fusarium damage in Canadian wheat using visible/near-infrared hyperspectral imaging

Fusarium damage in wheat may reduce the quality and safety of food and feed products. In this study, the use of hyperspectral imaging was investigated to detect fusarium damaged kernels (FDK) in Canadian wheat samples. More than 5,200 kernels, representing seven major Canadian wheat classes, with varying degree of infection symptoms ranging from sound through mild to severe were imaged in the visible-NIR (400–1,000 nm) wavelength range. Partial least squares discriminant analysis (PLS-DA) was used to segregate kernels into sound and damaged categories based on kernel mean spectra. A universal PLS-DA model based on four wavelengths was able to detect FDK in all seven classes with an overall accuracy of 90 % and false positives of 9 %.

Effect of 3B, 5A and 3A QTL for Fusarium head blight resistance on agronomic and quality performance of Canadian winter wheat

AbstractThe objectives of this study were to investigate (i) the correlations between Fusarium head blight (FHB) index, deoxynivalenol (DON) accumulation and percentage of Fusarium‐damaged kernels (FDK) with agronomic and quality traits and (ii) the effect associated with the presence of single QTLs for FHB resistance on agronomic and quality traits in winter wheat. The population was derived from the cross between ‘RCATL33' (FHB resistance derived from ‘Sumai 3’ and ‘Frontana’) and ‘RC Strategy’. Parental lines and recombinant inbred lines (RILs) were genotyped with SSR markers associated with the 3B, 5A and 3A QTLs. The population was planted in FHB‐inoculated nurseries and in agronomy trials. Lines in the 3B QTL class had the lowest FHB index, DON content and FDK level and did not have a significantly lower yield, thousand kernel weight or protein content compared with the lines grouped in other QTL classes (including no QTL class). Marker‐assisted selection of the 3B QTL for FHB resistance into high‐yielding FHB‐susceptible winter wheat is the recommended approach for the development of lines with increased FHB resistance without significant yield and quality penalties.

Molecular Characterization of Resistance to Fusarium Head Blight in U.S. Soft Red Winter Wheat Breeding Line VA00W‐38

ABSTRACTMany quantitative trait loci (QTL) in wheat (Triticum aestivum L.) conferring resistance to Fusarium head blight (FHB), caused by the Fusarium graminearium, have been mapped in diverse genetic sources. Use of nonadapted FHB resistant sources by breeding programs in the soft red winter (SRW) wheat region of the United States has not been very successful. Therefore, native sources of FHB resistance identified or validated in SRW wheat cultivars predominantly have been used. The breeding line VA00W‐38 has moderate FHB resistance and does not possess any previously identified exotic sources of resistance in its parentage. A set of 182 recombinant inbred lines (RILs) were developed from the cross VA00W‐38 × Pioneer brand ‘26R46’ and tested in field scab nurseries and natural conditions in two environments for each of 2 yr. Eight consistent QTL were identified on chromosomes 1BL, 2A, 2DL, 5B, 6A, and 7A and explained 6.5 to 21.3% of phenotypic variation of traits associated with FHB resistance. Their logarithm of odds (LOD) scores ranged from 2.5 to 6.7. Favorable alleles to decrease FHB are from VA00W‐38 except one QTL on chromosome 7A. Major QTL on chromosomes 2DL, 6A, and 5B decreased FHB index (IND), Fusarium damaged kernels (FDK), and deoxynivalenol (DON), respectively. Tightly linked markers identified for these consistent QTL can be used to select for favorable alleles associated with FHB resistance in breeding populations after validation in diverse genetic backgrounds.