Low Deoxynivalenol Content Research Articles

Reduction of Fusarium head blight and trichothecene contamination in transgenic wheat expressing Fusarium graminearum trichothecene 3-O-acetyltransferase.

Fusarium graminearum, the causal agent of Fusarium head blight (FHB), produces various mycotoxins that contaminate wheat grains and cause profound health problems in humans and animals. Deoxynivalenol (DON) is the most common trichothecene found in contaminated grains. Our previous study showed that Arabidopsis-expressing F. graminearum trichothecene 3-O-acetyltransferase (FgTRI101) converted DON to 3-acetyldeoxynivalenol (3-ADON) and excreted it outside of Arabidopsis cells. To determine if wheat can convert and excrete 3-ADON and reduce FHB and DON contamination, FgTRI101 was cloned and introduced into wheat cv Bobwhite. Four independent transgenic lines containing FgTRI101 were identified. Gene expression studies showed that FgTRI101 was highly expressed in wheat leaf and spike tissues in the transgenic line FgTri101-1606. The seedlings of two FgTri101 transgenic wheat lines (FgTri101-1606 and 1651) grew significantly longer roots than the controls on media containing 5 µg/mL DON; however, the 3-ADON conversion and excretion was detected inconsistently in the seedlings of FgTri101-1606. Further analyses did not detect 3-ADON or other possible DON-related products in FgTri101-1606 seedlings after adding deuterium-labeled DON into the growth media. FgTri101-transgenic wheat plants showed significantly enhanced FHB resistance and lower DON content after they were infected with F. graminearum, but 3-ADON was not detected. Our study suggests that it is promising to utilize FgTRI101, a gene that the fungus uses for self-protection, for managing FHB and mycotoxin in wheat production.

Bringing Barley Back: Analysis of Heritage Varieties for Use as Germplasm Sources to Improve Resistance against the Most Devastating, Contemporary Disease in Canada, Fusarium Head Blight (Fusarium graminearum)

Fusarium head blight (FHB), caused by Fusarium graminearum, is currently the most devastating disease for barley (Hordeum vulgare) in Canada. Associated mycotoxins can compromise grain quality, where deoxynivalenol (DON) is considered particularly damaging due to its frequency of detection. Breeding barley with a lower DON content is difficult, due to the poor adaptation and malt quality of resistance sources. A set of European-derived heritage varieties were screened in an FHB nursery in Charlottetown, PE, with selections tested at Brandon, MB, between 2018–2022. Genetic evaluation demonstrated a distinct clustering of Canadian varieties from the heritage set. At Brandon, 72% of the heritage varieties ranked lower for DON content than did the moderately resistant Canadian check ‘AAC Goldman’, but resistance was associated with later heading and taller stature. In contrast with Canadian modern malting variety ‘AAC Synergy’, general deficiencies were observed in yield, enzyme activity, and extract, along with higher protein content. Nonetheless, several resistant varieties were identified with reasonable a heading date and yield, including ‘Chevallier Chile’, ‘Domen’, ‘Djugay’, ‘Hannchen’, ‘Heils Franken’, ‘Moravian Barley’, ‘Loosdorfer’ with ‘Golden Melon’, ‘Nutans Moskva’, and ‘Vellavia’, these being some of the most promising varieties when malting quality characteristics were also considered. These heritage resources could be used as parents in breeding to develop FHB-resistant malting barley varieties.

Screening of an Ethyl Methane Sulfonate Mutagenized Population of a Wheat Cultivar Susceptible to Fusarium Head Blight Identifies Resistant Variants.

Fusarium head blight (FHB) primarily caused by Fusarium graminearum is a key disease of small grains. Diseased spikes show symptoms of premature bleaching shortly after infection and have aborted or shriveled seeds, resulting in reduced yields. The fungus also deteriorates quality and safety of the grain because of production of mycotoxins, especially deoxynivalenol (DON), which can result in grain being docked or rejected at the point of sale. Genetic host resistance to FHB is quantitative, and no complete genetic resistance against this devastating disease is available. Alternative approaches to develop new sources of FHB resistance are needed. In this study, we performed extensive forward genetic screening of the M4 generation of an ethyl methane sulfonate-induced mutagenized population of cultivar Jagger to isolate variants with FHB resistance. In field testing, 74 mutant lines were found to have resistance against FHB spread, and 30 of these lines also had low DON content. Subsequent testing over 2 years in controlled greenhouse conditions revealed 10 M6 lines showing significantly lower FHB spread. Seven and 6 of those 10 lines also had reduced DON content and fewer Fusarium-damaged kernels, respectively. Future endeavors will include identification of the mutations that led to resistance in these variants.

Characterization of QTL and eQTL controlling early Fusarium graminearum infection and deoxynivalenol levels in a Wuhan 1 x Nyubai doubled haploid wheat population

BackgroundFusarium head blight (FHB) is a major disease of cereal crops, caused by the fungal pathogen Fusarium graminearum and related species. Breeding wheat for FHB resistance contributes to increase yields and grain quality and to reduce the use of fungicides. The identification of genes and markers for FHB resistance in different wheat genotypes has nevertheless proven challenging.ResultsIn this study, early infection by F. graminearum was analyzed in a doubled haploid population derived from the cross of the moderately resistant wheat genotypes Wuhan 1 and Nyubai. Three quantitative trait loci (QTL) were identified: 1AL was associated with lower deoxynivalenol content, and 4BS and 5A were associated with reduced F. graminearum infection at 2 days post inoculation. Early resistance alleles were inherited from Wuhan 1 for QTL 1AL and 4BS and inherited from Nyubai for the 5A QTL. Cis and trans expression QTL (eQTL) were identified using RNA-seq data from infected head samples. Hotspots for trans eQTL were identified in the vicinity of the 1AL and 4BS QTL peaks. Among differentially expressed genes with cis eQTL within the QTL support intervals, nine genes had higher expression associated with FHB early resistance, and four genes had higher expression associated with FHB early susceptibility.ConclusionsOur analysis of genotype and gene expression data of wheat infected by F. graminearum identified three QTL associated with FHB early resistance, and linked genes with eQTL and differential expression patterns to those QTL. These findings may have applications in breeding wheat for early resistance to FHB.

Fusarium culmorum Tri genes and barley Hvugt13248 gene transcription in infected barley cultivars

The transcription activities of genes somehow associated with the mycotoxin deoxynivalenol (DON) biosynthesis, namely Fusarium Tri genes, and the barley gene coding for UDP-glycosyltransferase (HvUGT13248) on different genetic backgrounds were compared. Determining the amount of the pathogen DNA was used as a useful tool for evaluating the infestation of barley cultivars. Amounts of the pathogen DNA differed in six barley cultivars infected by F. culmorum. Transcription of HvUGT13248 was related to DON content in the samples. Low pathogenic infection and low DON content were accompanied by increased Fusarium Tri10 transcription in resistant cv. Amulet. This finding confirmed our recent results and makes us propose using this change as a possible marker of barley resistance against Fusarium.

Registration of Near-Isogenic Winter Wheat Germplasm Contrasting in Fhb1 for Fusarium Head Blight Resistance

The Chinese wheat germplasm Ning7840 (Triticum aestivum L.) contains Fhb1, a quantitative trait locus (QTL) for Fusarium head blight (FHB) resistance that explains as much as 53% of the phenotypic variation in segregating populations. Ning7840 has been widely used as a resistant parent in breeding programs worldwide, but because of its poor adaptation in the United States, its progenies usually exhibit reduced grain yield due to the transfer of undesirable genes from Ning7840. The development of five near-isogenic lines (NILs: ‘Clark’*7/Ning7840) (NIL75, Reg. No. GS-174, PI 668559; NIL78, Reg. No. GS-175, PI 668560; NIL80, Reg. No. GS-176, PI 668561; NIL90, Reg. No. GS-177, PI 668562; NIL98, Reg. No. GS-178, PI 668563) contrasting in Fhb1 alleles was intended to overcome this potential limitation. Marker-assisted backcrossing was used to develop the NILs. Approximately 2000 BC7F2 plants from the backcross of Ning7840 by Clark (recurrent parent) were screened with two Fhb1-flanking markers (Xgwm533 and Xgwm493), and selected BC7F3 families were evaluated for FHB resistance in greenhouses. Both genotypic and phenotypic data confirm the presence of Fhb1 in the four resistant NILs and absence in the one susceptible NIL. All resistant NILs had significantly higher FHB resistance and lower deoxynivalenol content than Clark and the susceptible NIL but yield similar to Clark (P = 0.295). Marker-assisted backcross efficiently transferred Fhb1 into U.S. hard winter wheat without transferring undesirable traits from Ning7840, and these Fhb1 NILs should be useful parents for effective use of Fhb1 in U.S. winter wheat.

Near‐Infrared Spectroscopic Method for Identification of Fusarium Head Blight Damage and Prediction of Deoxynivalenol in Single Wheat Kernels

ABSTRACTFusarium Head Blight (FHB), or scab, can result in significant crop yield losses and contaminated grain in wheat (Triticum aestivum L.). Growing less susceptible cultivars is one of the most effective methods for managing FHB and for reducing deoxynivalenol (DON) levels in grain, but breeding programs lack a rapid and objective method for identifying the fungi and toxins. It is important to estimate proportions of sound kernels and Fusarium‐damaged kernels (FDK) in grain and to estimate DON levels of FDK to objectively assess the resistance of a cultivar. An automated single kernel near‐infrared (SKNIR) spectroscopic method for identification of FDK and for estimating DON levels was evaluated. The SKNIR system classified visually sound and FDK with an accuracy of 98.8 and 99.9%, respectively. The sound fraction had no or very little accumulation of DON. The FDK fraction was sorted into fractions with high or low DON content. The kernels identified as FDK by the SKNIR system had better correlation with other FHB assessment indices such as FHB severity, FHB incidence and kernels/g than visual FDK%. This technique can be successfully employed to nondestructively sort kernels with Fusarium damage and to estimate DON levels of those kernels. Single kernels could be predicted as having low (<60 ppm) or high (>60 ppm) DON with ≈96% accuracy. Single kernel DON levels of the high DON kernels could be estimated with R2 = 0.87 and standard error of prediction (SEP) of 60.8 ppm. Because the method is nondestructive, seeds may be saved for generation advancement. The automated method is rapid (1 kernel/sec) and sorting grains into several fractions depending on DON levels will provide breeders with more information than techniques that deliver average DON levels from bulk seed samples.

Diallel Analysis of Fusarium Head Blight Resistance in Wheat

Fusarium head blight (FHB) negatively impacts grain yield and quality of wheat (Triticum aestivum L. em. Thell) worldwide, especially when warm, humid weather prevails during flowering and grain filling. Our objective was to determine the mechanism of genetic control of FHB resistance in selected winter and spring wheat germplasm. Six genotypes, ‘Nekota’ (A), ‘2137’ (B), ‘Harding’ (C), ‘Ning7840’ (D), ‘ND2710’ (E) and ‘BacUp’ (F), were included in a modified diallel. The F1 and F2 populations were evaluated in a greenhouse, whereas only F2 populations were evaluated in a mist-irrigated field nursery. Plants were artificially inoculated with Fusarium graminearum Schwabe isolates in both environments. Additive gene effects were more important than non-additive gene effects. General combining ability (GCA) effects were significant in both F1 and F2 populations in both environments. Specific combining ability (SCA) effects were significant only in the greenhouse environment for F2. Combining ability ratio (0.66 to 0.89) was high, and narrow-sense heritability (0.40 to 0.64) was moderate. Parents D and E had large positive GCA effects for resistance to FHB. Parent B had the largest negative GCA effect for susceptibility to FHB. Graphical analysis of data based on the biplot method was also used to visualize the data and showed that the D/E cross had the lowest percentages of uninfected kernels. Lines D and E had the best resistance to deoxynivalenol (DON) accumulation. Percentages of uninfected kernels and DON content were negatively and significantly correlated in the F1 (r = −0.71, P < 0.01) and F2 (r = −0.84, P < 0.01) greenhouse environments. Multiple field tests across years and locations are needed to confirm whether or not selecting for low disease index will identify genotypes with low DON content. Parents D and E, both ‘Sumai3’ derivatives, contributed resistance to FHB and were better than F, which is a ‘Nuy Bay’ derivative. Parent B must be avoided in FHB resistance breeding programs because of its susceptibility and undesirable negative GCA effect.

Trichothecene-mediated in vitro selection in wheat for reduced mycotoxin accumulation caused by Fusarium graminearum

Trichothecene, a factor of aggressiveness of Fusarium graminearum in wheat fusarium head blight (FHB), was evaluated in an anther co-culture assay for the regeneration of doubled haploid (DH) lines with reduced mycotoxin accumulation. A Fusarium graminearum culture filtrate and a defined mixture of purified trichothecenes were compared with a control treatment in two F1-derived microspores populations. Frontana and Katepwa were the FHB resistant and intermediate resistant sources, respectively, and the cultivar Norseman was the FHB susceptible parent. A preliminary evaluation of the subpopulations of DH lines, using the point inoculation method in the greenhouse, showed selection effects for FHB resistance in the trichothecene co-cultured Frontana/Norseman subpopulation only. Three years of field evaluation using the spray inoculation method revealed that the DH subpopulation from the F1 hybrid Frontana/Norseman co-culture in the presence of trichothecenes accumulated consistently less deoxynivalenol (DON) in the grain than the control subpopulation. The FHB symptoms were also significantly reduced for 1 yr (2001) in the same subpopulation. This subpopulation showed increased test weight, plant height and a 1.1-d delay in heading date when compared with the control subpopulation, under disease pressure. A trichothecene co-cultured DH subpopulation from Katepwa/Norseman also had a significantly lower DON content for 1 yr. Key words: Androgenesis, disease resistance, Gibberella zeae, mycotoxin, Triticum aestivum, wheat scab

New Fusarium Head Blight‐Resistant Sources from Asian Wheat Germplasm

Fusarium head blight (FHB) is an important disease of wheat worldwide. Severe infection can dramatically reduce grain yield and quality. Resistant cultivars have been identified from several countries. However, only a few sources of FHB resistance showed stable FHB resistance across environments and have been used as the major source of resistance in breeding programs. To diversify the wheat FHB‐resistance gene pool, new sources of FHB‐resistance are desired. Ninety‐four selected wheat landraces and cultivars, mainly from China and Japan, have been evaluated for FHB severity and deoxynivalenol (DON) content. Low DON content was correlated with resistance to the FHB symptom spread within an infected spike, but not with the resistance to FHB initial infection. Two‐thirds of the accessions were either resistant or moderately resistant to FHB. Among them, 26 highly resistant accessions mainly originated from China and Japan. Fifteen of them had less than 2 mg kg−1 DON in harvested grain, six of which showed all three types of resistance. Most of these resistant accessions lack known pedigree relations to Sumai 3, suggesting that some of them may carry genes for resistance to FHB and DON accumulation different from those in Sumai 3.

Response to Fusarium culmorum inoculation in barley

AbstractIn field tests replicated in 2004 and 2005, 32 cultivars of spring barley were assessed for resistance to Fusarium head blight (FHB) by single floret inoculation and spray inoculation with Fusarium culmorum (W. G. Smith) Sacc. It was found that the weather conditions in individual years affect to a large extent the progression of FHB and production of mycotoxin deoxynivalenol (DON). At the same time, in both years the cultivars reacted to F. culmorum infection similarly with respect to areas under disease progress curve (AUDPC) values and content of mycotoxin DON. Spraying inoculation led to stronger infection. The biggest differences in AUDPC values were observed between the cultivars Brise and Celinka, and weak reaction was found in the cultivars Kompakt and Madonna. The cultivars Kompakt and Tolar were most resistant towards FHB. In both monitored years the variety Ludan contained the lowest amounts of mycotoxin DON. Cultivars with high infection and low DON content (r = 0.78) showed weak positive relationship between resistance to FBH and accumulation of DON (concentration 70–200 mg/kg). This is the first information on FHB and in vivo concentrations of DON in certificated barley cultivars in Slovakia.

Quantitative Trait Loci Controlling Fusarium Head Blight Resistance and Low Deoxynivalenol Content in Hexaploid Wheat Population from ‘Arina’ and NK93604

ABSTRACTBreeding for Fusarium head blight (FHB) resistant wheat adapted to the Norwegian climatic conditions is one of the top priorities in the country. This study was conducted to characterize QTLs for FHB resistance and low deoxynivalenol (DON) content in a population of 93 double haploid lines from a cross between ‘Arina’ and NK93604. Both parents have moderate levels of resistance to FHB. The population was assessed for FHB resistance under field conditions for 3 yr (2001 to 2003), and DON content was analyzed from seed samples in the 2002 experiment. The two traits showed significant genetic variation and were significantly correlated with each other. Composite interval mapping (CIM) identified four QTLs using the 3 yr mean for FHB resistance on chromosomes 1AL, 1BL, 6BS, and 7AL. The QTLs on 1AL, 1BL, and 7AL were consistently detected in all 3 yr, and explained 27.9, 19.6, and 14.8% of the phenotypic variation, respectively. The QTLs on chromosomes 1BL and 6BS originated from Arina, whereas those on 1AL and 7AL were from NK93604. None of the QTLs for FHB resistance detected in this study were coincident with those previously reported in the Arina/‘Forno’ population. Two major QTLs, both derived from NK93604, on chromosomes 1AL and 2AS were identified for DON content that explained 27.9 and 26.7% of the variation, respectively. A major QTL for FHB resistance on 1AL coincided with a QTL for DON content. As far as we are aware, the QTL on chromosome 1AL is novel and not reported elsewhere. Data from the present study provides breeders with additional information on chromosomal regions associated with FHB resistance and DON content in European wheats and will help guide the development of FHB‐resistant wheat.

Deletion of a Chromosome Arm Altered Wheat Resistance to Fusarium Head Blight and Deoxynivalenol Accumulation in Chinese Spring.

Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe, is an important disease of wheat worldwide. Production of deoxynivalenol (DON) in infected wheat grain by F. graminearum is a major safety concern when considering use of the grain as feed for livestock or for human consumption. Determining chromosome locations of FHB-related genes may facilitate enhancement of wheat resistance to FHB and DON accumulation. In this study, a set of 30 ditelosomic lines derived from Chinese Spring, a moderately FHB-resistant landrace from China, were evaluated for proportion of scabbed spikelets per inoculated spike in the greenhouse and for DON contamination in harvested grain over 2 years. Significant variation in the proportion of scabbed spikelets was observed among ditelosomic lines, ranging from 13 to 95%. Seven ditelosomic lines exhibited a greater proportion of scabbed spikelets and three of these also had greater DON content than Chinese Spring (P = 0.01), suggesting that those missing chromosome arms may carry genes that contribute to resistance to FHB. Six ditelosomic lines had a reduction in proportion of scabbed spikelets, suggesting that susceptibility factors or resistance suppressors may be on these missing chromosomal arms. Selection for low proportion of scabbed spikelets in general will select for low DON content.

Evaluation of spring barley genotypes with different susceptibility to Fusarium head blight using molecular markers

One of cereal diseases that has gained a greater importance for growers, processing industry as well as for breeders in many regions of the world is Fusarium head blight (FHB) caused by fungi of the Fusarium genus. The objectives of this study were to test diversity among spring barley breeding lines exhibiting various sensitivity to FHB and to find RAPD markers and AFLP markers that will distinguish between susceptible and resistant and/or moderately resistant genotypes. A test of a set of spring barley genotypes artificially infected by fusaria in field trials was carried out. Based on the results from field and laboratory evaluation and deoxynivalenol (DON) content assessment, barley genotypes with different responses to FHB were selected. The genotypes were hybridized and doubled haploid (DH) lines were derived in F&lt;sub&gt;1&lt;/sub&gt; generation using the in vitro androgenesis method. Initial parental components and derived DH lines were tested for FHB infection and DON content. A set of parental genotypes of spring barley was tested with 80 RAPD markers. A RAPD marker (H30) was detected which enabled to distinguish between very susceptible parental genotypes and other resistant or moderately resistant spring barley genotypes based on the fragment of about 1300 bp. This specific product was screened in 23 DH lines derived from crosses of parental genotypes of spring barley and detected in 10 DH lines. During the study, some DH lines were selected that exhibited improved resistance to Fusarium infection. A low infection level and low DON content was found in the line DH&amp;nbsp;4/2 derived from CI 4196 &amp;times; Foster. The AFLP technique was used to analyse parental genotypes of spring barley. The detected markers can be further evaluated and employed to select breeding materials.

Quantitative trait loci for resistance to fusarium head blight and deoxynivalenol accumulation in Wangshuibai wheat under field conditions

Wangshuibai is a Chinese landrace wheat with a high level of resistance to fusarium head blight (FHB) and deoxynivalenol (DON) accumulation. Using an F7 population of recombinant inbred lines (RILs) derived from the cross between Wangshuibai and Annong 8455 for molecular mapping of quantitative trait loci (QTL) for FHB resistance, the proportion of scabbed spikelets (PSS) and DON content were assessed under field conditions. Composite interval mapping revealed that two and three QTL were significantly associated with low PSS and low DON content, respectively, over 2 years. QTL on chromosomes 3B and 2A explained 17 and 11·5%, respectively, of the phenotypic variance for low PSS, whereas QTL on chromosomes 5A, 2A and 3B explained 12·4, 8·5 and 6·2%, respectively, of the phenotypic variance for low DON content. The 3B QTL appeared to be associated mainly with low PSS, and the 5A QTL primarily with low DON content in Wangshuibai. The 2A QTL had minor effects on both low PSS and DON content. Microsatellite and AFLP markers linked to these QTL should be useful for marker‐assisted selection of QTL for low PSS and low DNA content from Wangshuibai.

Reaction of a Diverse Collection of Barley Lines to Fusarium Head Blight.

Fusarium head blight (FHB) is currently the primary disease of concern in barley in Canada and sources of FHB resistance need to be identified. A diverse collection of 77 two-rowed and 81 six-rowed barley lines was screened for resistance to FHB in inoculated, irrigated nurseries from 1995 to 1998. Barley spikes were spray inoculated with conidia of Fusarium graminearum and visual symptoms of FHB were scored to determine an FHB index. Deoxynivalenol (DON) content was determined from harvested seed samples during 1997 and 1998. Although there was variation in the average FHB index and DON content among the different years of testing, the rankings of the lines generally were correlated among the years of testing and the two measures of FHB. Based on the FHB index from 1995 and 1996, a subset of 18 lines with low FHB and 12 lines with high FHB were compared with 20 FHB resistance sources and 7 Canadian lines or cultivars during 1997 and 1998 in both inoculated and noninoculated nurseries. Lines Nepolegajuscij, Krasnojarskij, Nordic, Murakaki-mochi, Golozernyj 1, Maris Mink, Symko, Ussurijskij 8, Suvenir, and Canadian cultivars AC Sterling and Morrison were similar to the best resistance sources (Zhedar1, Seijo II, and Chevron) and had consistently low DON content.

Estimation of deoxynivalenol (DON) content by symptom rating and exoantigen content for resistance selection in wheat and triticale

Fusarium head blight (FHB) in wheat and triticale leads to contamination of the grain with the mycotoxin deoxynivalenol (DON) that is harmful to animal and man. A fast, low-cost, and reliable method for quantification of the DON content in the grain is essential for selection. We analysed 113 wheat and 55 triticale genotypes for their symptom development on spikes, Fusarium exoantigen (ExAg) and DON content in the grain after artificial inoculation with a highly aggressive isolate of F. culmorum in three (wheat) and six (triticale) location-by-year combinations. Additionally, in triticale the amount of Fusarium damaged kernels (FDK) was assessed. ExAg content was analysed by a newly developed Fusarium-specific plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA) and DON content by an immunoassay. A moderate disease severity resulted in an ExAg content of 0.87 optical density (OD) units in wheat and 1.02 OD in triticale. DON content ranged from 12.0 to 105.2 mg kg−1 in wheat and from 24.2 to 74.0 mg kg−1 in triticale. Genotypic and genotype-by-environment interaction variances were significant (P < 0.01). Coefficient of phenotypic correlation between DON content analysed by the immunoassay and ExAg content was r = 0.86 for wheat and r = 0.60 for triticale. The highest correlation between DON content and symptom rating was found by FHB rating in wheat (r = 0.77) and by FDK rating in triticale (r = 0.71). In conclusion, selection for reduced FHB symptoms should lead to a correlated selection response in low fungal biomass and low DON content in the grain.

Deoxynivalenol (DON) Content and Fusarium Head Blight Resistance in Segregating Populations of Winter Rye and Winter Wheat

Fusarium head blight (FHB), caused by Fusarium graminearum Schw. [teleomorph: Gibberella zeae (Schw.) Petch] and Fusarium culmorum (W.G. Sm.) Sacc., is a devastating disease in cereals, resulting in yield loss and contamination of harvested grains with mycotoxins, mainly deoxynivalenol (DON) and 3-acetyl DON (3-ADON). This study was undertaken to evaluate the possibility of selecting to reduced DON content and FHB resistance early in a breeding program. We estimated the genetic variance among F 3 lines in winter rye (Secale cereale L.) and winter wheat (Triticum aestivum L.) and the association between the two traits. In field experiments, four rye and one wheat populations with a total of 218 and 77 progenies, respectively, together with their parental lines were inoculated in four location-year combinations (environments) with an isolate of F. culmorum that produced high levels of DON. Grain DON and 3-ADON contents were determined by an enzyme immunoassay and head blight severity was assessed. Additionally, a total of 166 rye samples were analyzed by gas chromatography with mass spectrometry (GC-MS). The two methods were highly correlated (0.9). Mean DON contents ranged from 20 to 129 mg kg -1 , and mean disease severity from 3.8 to 6.8 on the 1-to-9 scale. The parental means generally resembled the means of their respective F3 progenies. Significant (P = 0.01) genotypic variance was detected, but genotype × environment interaction was also high (P = 0.01) for the two traits. Grain DON content, however, showed lower heritabilities than head blight rating, especially in rye. Coefficients of phenotypic correlation between FHB severity and DON content, therefore, were only in the medium range for rye (0.3-0.7) and higher for wheat (0.8). Genotypic correlation coefficients generally showed a tight association in both rye and wheat (0.8-0.9). Transgressive segregants for higher DON content were found in three rye populations and for higher FHB resistance in one rye population. Selection for lower grain DON content and FHB resistance can be effectively started by plant breeders as early as in the F 3 generation. Lines with low DON content can be indirectly achieved by selecting for reduced head blight severity across environments.

Deoxynivalenol (DON) Content and Fusarium Head Blight Resistance in Segregating Populations of Winter Rye and Winter Wheat

Fusarium head blight (FHB), caused by Fusarium graminearum Schw. [teleomorph: Gibberella zeae (Schw.) Petch] and Fusarium culmorum (W.G. Sm.) Sacc., is a devastating disease in cereals, resulting in yield loss and contamination of harvested grains with mycotoxins, mainly deoxynivalenol (DON) and 3-acetyl DON (3-ADON). This study was undertaken to evaluate the possibility of selecting to reduced DON content and FHB resistance early in a breeding program. We estimated the genetic variance among F3 lines in winter rye (Secale cereale L.) and winter wheat (Triticum aestivum L.) and the association between the two traits. In field experiments, four rye and one wheat populations with a total of 218 and 77 progenies, respectively, together with their parental lines were inoculated in four location–year combinations (environments) with an isolate of F. culmorum that produced high levels of DON. Grain DON and 3-ADON contents were determined by an enzyme immunoassay and head blight severity was assessed. Additionally, a total of 166 rye samples were analyzed by gas chromatography with mass spectrometry (GC-MS). The two methods were highly correlated (0.9). Mean DON contents ranged from 20 to 129 mg kg−1, and mean disease severity from 3.8 to 6.8 on the 1-to-9 scale. The parental means generally resembled the means of their respective F3 progenies. Significant (P = 0.01) genotypic variance was detected, but genotype × environment interaction was also high (P = 0.01) for the two traits. Grain DON content, however, showed lower heritabilities than head blight rating, especially in rye. Coefficients of phenotypic correlation between FHB severity and DON content, therefore, were only in the medium range for rye (0.3–0.7) and higher for wheat (0.8). Genotypic correlation coefficients generally showed a tight association in both rye and wheat (0.8–0.9). Transgressive segregants for higher DON content were found in three rye populations and for higher FHB resistance in one rye population. Selection for lower grain DON content and FHB resistance can be effectively started by plant breeders as early as in the F3 generation. Lines with low DON content can be indirectly achieved by selecting for reduced head blight severity across environments.