Oat Accessions Research Articles

Targeting sources of drought tolerance within an Avena spp. collection through multivariate approaches

In this study, we find and characterize the sources of tolerance to drought amongst an oat (Avena sativa L.) germplasm collection of 174 landraces and cultivars. We used multivariate analysis, non-supervised principal component analyses (PCA) and supervised discriminant function analyses (DFA) to suggest the key mechanism/s responsible for coping with drought stress. Following initial assessment of drought symptoms and area under the drought progress curve, a subset of 14 accessions were selected for further analysis. The collection was assessed for relative water content (RWC), cell membrane stability, stomatal conductance (g (1)), leaf temperature, water use efficiency (WUE), lipid peroxidation, lipoxygenase activity, chlorophyll levels and antioxidant capacity during a drought time course experiment. Without the use of multivariate approaches, it proved difficult to unequivocally link drought tolerance to specific physiological processes in the different resistant oat accessions. These approaches allowed the ranking of many supposed drought tolerance traits in the order of degree of importance within this crop, thereby highlighting those with a causal relationship to drought stress tolerance. Analyses of the loading vectors used to derive the PCA and DFA models indicated that two traits involved in water relations, temperature and RWC together with the area of drought curves, were important indicators of drought tolerance. However, other parameters involved in water use such as g (1) and WUE were less able to discriminate between the accessions. These observations validate our approach which should be seen as representing a cost-effective initial screen that could be subsequently employed to target drought tolerance in segregating populations.

Diversity of North European oat analyzed by SSR, AFLP and DArT markers

Oat is an important crop in Nordic countries both for feed and human consumption. Maintaining a high level of genetic diversity is essential for both breeding and agronomy. A panel of 94 oat accessions was used in this study, including 24 museum accessions over 100- to 120-year old and 70 genebank accessions from mainly Nordic countries and Germany, covering different breeding periods. Sixty-one polymorphic SSR, 201 AFLP and 1056 DArT markers were used to evaluate the past and present genetic diversity of the Nordic gene pool. Norwegian accessions showed the highest diversity, followed by Swedish and Finnish, with German accessions the least diverse. In addition, the Nordic accessions appeared to be highly interrelated and distinct from the German, reflecting a frequent germplasm exchange and interbreeding among Nordic countries. A significant loss of diversity happened at the transition from landraces and old cultivars to modern cultivars. Modern oat originated from only a segment of the landraces and left the remainder, especially black oat, unused. However, no significant overall diversity reduction was found during modern breeding periods, although fluctuation of diversity indices was observed. The narrow genetic basis of the modern Nordic gene pool calls for increasing genetic diversity through cultivar introduction and prebreeding based on neglected sources like the Nordic black oat.

Screening of parent material for breeding oat varieties resistant to Fusarium disease and accumulation of mycotoxins in grain

Oat accessions characterized by multicomponent resistance to Fusarium disease of grain from the collection of the Vavilov All-Russian Research Institute of Plant Industry (VIR) are selected. Resistance of the accessions is evaluated on the basis of three parameters: Fusarium damaged grain (FDG): percent of infected grain, quantity of mycotoxins, and DNA content of trichothecene-producing fungi. Five oat landrace accessions and two cultivars Argamak (Russia) and Kuromi (Japan) are the most resistant to infection of grain and accumulation of mycotoxins.

Characterisation of oat genetic resources using electrophoresis of avenins

The prolamin (avenin) patterns of  oat (Avena sativa L.) cultivars released in  the Czech Republic and in the former Czechoslovak Republic were analysed  by acid polyacrylamide gel electrophoresis (A-PAGE).  Forty-nine oat (Avena sativa L.) accessions of domestic origin, maintained in the Czech collection of oat genetic resources, were analysed. The evaluated set contained 18 modern  and 31 old cultivars. Thirty accessions showed a homogeneous prolamin pattern. The other accessions were heterogeneous with two or three different patterns, present at different percentages. Heterogeneity was present in 48% of the old cultivars, but  only in 22% of the modern cultivars. Identity indexes within the heterogeneous accessions were calculated. The index values ranged from 0.09 to 0.75. Only in two heterogeneous cultivars (Dětenický Bílý, Valečovský Bílý) the identity index between their components was higher than 0.6, indicating, that their components were most likely sister lines. All analysed cultivars could be unambiguously distinguished by their prolamin pattern. The obtained prolamin patterns will be used to complete descriptor data of the genetic resources  and might be useful also in oat breeding and research. 

Sterile oat (Avena sterilis L.) cross-resistance profile to ACCase-inhibiting herbicides in Greece

Sterile oat (Avena sterilis) is the most widely distributed, abundant and harmful weed in the winter cereals grown in Greece. Its effective control has relied for the past three decades upon the ACCase-inhibiting herbicides. However, recently many growers in northern and central Greece have experienced reduced sterile oat control after the application of fenoxaprop-p-ethyl or clodinafop-propargyl. Preliminary screening indicated that less than 80% of the treated plants in 36 and 43 out of 125 sterile oat accessions were killed (R, resistant) by the application of the four times the recommended dose of fenoxaprop-p-ethyl (R-Fx) or clodinafop-propargyl (R–Cd), whereas less than 80% of the treated plants in 29 of them were killed by both herbicides applied at four times the recommended dose. Also, more than 80% of the treated plants in 42 and 35 accessions were killed by the four times the recommended dose (r, partially resistant) of fenoxaprop-p-ethyl (r-Fx) or clodinafop-propargyl (r-Cd), respectively. Finally, more than 80% of the treated plants in 47 and 47 accessions were killed (S, susceptible) by the recommended dose of fenoxaprop-p-ethyl (S-Fx) or clodinafop-propargyl (S-Cd), respectively, whereas more than 80% of the treated plants in 36 of these accessions were killed by the recommended dose of both herbicides. The whole-plant dose-response method used to evaluate 17 R-Fx and five S-Fx accessions showed that 16, 17, 11, and two R-Fx accessions were cross-resistant to clodinafop-propargyl, diclofop-methyl, tralkoxydim, and pinoxaden, respectively. In particular, more than 50% of the treated plants in 12, 12, 17, and three accessions survived the respective application of the four times the recommended dose of fenoxaprop-p-ethyl, clodinafop-propargyl, diclofop-methyl, and tralkoxydim. Regarding pinoxaden, 3, 17 and 20% of the treated plants in three accessions survived its application at four times the recommended dose. All R and the S accessions were effectively controlled by the recommended dose of imazamox and mesosulfuron-methyl + iodosulfuron methyl-sodium. These results strongly suggest that cross-resistance to ACCase-inhibiting herbicides has been developed for sterile oat. Therefore, measures should be taken for crop rotation when possible or rotational use of the available ALS- and ACCase-inhibiting herbicides in order to reduce the potential for development of sterile oat multiple resistance. Regarding the accessions with cross-resistance to APP, CHD and PPZ, these could be effectively controlled by the application of mesosulfuron-methyl + iodosulfuron methyl-sodium.

Diclofop resistance in sterile wild oat ( Avena sterilis L.) in wheat fields in Greece and its management by other post-emergence herbicides

In 2009, a survey was conducted of cereal fields in five prefectures of Greece to establish the frequency and distribution of herbicide-resistant sterile wild oat ( Avena sterilis L.). In total, 104 sterile wild oat accessions were collected and screened in a field experiment (conducted in 2009 and repeated in 2010) with several herbicides commonly used to control this weed. Most of the sterile wild oat accessions (89%) were classed as resistant (or developing resistant) to the ACCase-inhibiting herbicide diclofop, while resistance to other ACCase-inhibiting herbicides was markedly lower. The results of the pot experiments showed that some of the sterile wild oat accessions were found to have a very high level of diclofop resistance (resistance index up to 28.6), while cross-resistance with other herbicides was common. The levels of resistance and cross-resistance patterns varied among biotypes with different amount and time of selection pressure, indicating either more than one mechanism of resistance or different resistance mutations in these sterile wild oat biotypes. LA14, which had the highest diclofop resistance level (28.6 resistance index), showed resistance to all APP herbicides applied and non-ACCase inhibitors. Alternative ACCase-inhibiting herbicides, namely tralkoxydim and pinoxaden remain effective on 86 and 92% of the tested sterile wild oat populations, respectively. For the ALS-inhibiting herbicide mesosulfuron + iodosulfuron, nearly all the sterile wild oat accessions were susceptible (97%), with only 3 of them classed as developing resistance. Therefore, there is an opportunity to effectively control sterile wild oat by selecting from a wide range of herbicides and other cultural practices. Early post-emergence herbicide application is strongly suggested, since it could decrease the number of resistant seeds in the field and slow down the dispersal of this major problem.

Assessment of distribution and diversity of Avena sterilis L. and Avena fatua L. in cereal crops of Greece based on a 3-year survey and selected morphological traits

Under the view of species genetic erosion and the need of better crops, wild species could become important germplasm sources for breeding. At present, several wild Avena species are used as donors of valuable characters in oat breeding. In this study, wild oat distribution and diversity in wheat, barley and oat fields of Greece was examined by means of a 3-year survey in some typical cereal producing regions in the central part of the country. Greenhouse experiments were also conducted in order to compare seedlings grown from wild oat accessions of these regions under the same conditions. A total of 151 fields were surveyed and 158 accessions of wild oats were studied in terms of some morphological traits. The occurrence and distribution of A. sterilis was very high, while a noticeable and first-time analytically reported presence of A. fatua was evident in some of the surveyed wheat fields. The high diversity of wild oat was furthermore indicated by means of the pot experiments. The high degree of phenotypic variation in A. sterilis could be attributed to the earlier introduction of this species in the sampling area, compared to A. fatua. Wild oat distribution and diversity in a region seems crucial for the cereal production and is an important parameter which must be considered in evaluating efficacy of weed control strategies, while genes controlling these characters could be potentially used to improve cultivated forms of oats or other cereals.

Hybrids of Avena sativa with two diploid wild oats (CIav6956) and (CIav7233) resistant to crown rust

Two diploid accessions of wild oat, CIav6956 and CIav7233, were identified as carrying seedling resistance to oat crown rust (caused by Puccinia coronata f. sp. avenae; Pca). Two vigorous interploidy F1 hybrids were generated from crosses involving the hexaploid oat cultivar Wintaroo and the diploid oat Avena strigosa Schreb. accession CIav6956. An additional interploidy F1 hybrid, designated “F1-Aa1”, was produced from a cross of Wintaroo and the diploid oat accession CIav7233. All three hybrids were more vigorous and taller than the cultivated parent Wintaroo. The three F1 hybrids contained full chromosome complements from both parents (2n = 4x = 28), but no seeds were obtained when the three F1 hybrids were selfed. Meiotic analyses of the hybrids indicated that they exhibited a high degree of inter-genome and intra-genome pairing. Trivalent configurations were detected in 95–96% of meiotic cells and a minimum of three bivalents was present in all cells. An average chiasma frequency of 7.2–7.9 per cell was observed for the three F1 hybrids. A fourth F1 hybrid was subsequently generated from a cross between the diploid oat accession CIav7233 and Wintaroo. One octaploid (2n = 8x = 56) was generated from this hybrid and progeny were resistant to two Pca races. The chromosome number of the octaploid progeny varied between 51 and 54 chromosomes. Development of a chromosome addition line(s) with the crown rust resistance should be possible from these partial-octaploids.

New DArT markers for oat provide enhanced map coverage and global germplasm characterization

BackgroundGenomic discovery in oat and its application to oat improvement have been hindered by a lack of genetic markers common to different genetic maps, and by the difficulty of conducting whole-genome analysis using high-throughput markers. This study was intended to develop, characterize, and apply a large set of oat genetic markers based on Diversity Array Technology (DArT).ResultsApproximately 19,000 genomic clones were isolated from complexity-reduced genomic representations of pooled DNA samples from 60 oat varieties of global origin. These were screened on three discovery arrays, with more than 2000 polymorphic markers being identified for use in this study, and approximately 2700 potentially polymorphic markers being identified for use in future studies. DNA sequence was obtained for 2573 clones and assembled into a non-redundant set of 1770 contigs and singletons. Of these, 705 showed highly significant (Expectation < 10E-10) BLAST similarity to gene sequences in public databases. Based on marker scores in 80 recombinant inbred lines, 1010 new DArT markers were used to saturate and improve the 'Kanota' × 'Ogle' genetic map. DArT markers provided map coverage approximately equivalent to existing markers. After binning markers from similar clones, as well as those with 99% scoring similarity, a set of 1295 non-redundant markers was used to analyze genetic diversity in 182 accessions of cultivated oat of worldwide origin. Results of this analysis confirmed that major clusters of oat diversity are related to spring vs. winter type, and to the presence of major breeding programs within geographical regions. Secondary clusters revealed groups that were often related to known pedigree structure.ConclusionThese markers will provide a solid basis for future efforts in genomic discovery, comparative mapping, and the generation of an oat consensus map. They will also provide new opportunities for directed breeding of superior oat varieties, and guidance in the maintenance of oat genetic diversity.

Duplication assessments in Nordic Avena sativa accessions at the Canadian national genebank

This study applied two methods to assess intra-collection duplication within 339 Nordic oat (Avena sativa L.) accessions preserved by Plant Gene Resources of Canada (PGRC). Putative duplicates, that is accessions carrying a similar accession name, were grouped into 52 duplication groups and included 230 of the 339 Nordic oat accessions. A field assessment based on visual inspection of field plots was conducted during two growing seasons to detect distinct phenotypes within each duplication group. Simultaneously, a descriptor assessment using seven characters with altogether sixteen character states was used in both years for the same purpose. The combined results of both assessments and both years indicated that among the 230 accessions in duplication groups only 118 could be identified as distinct. This would allow for a reduction of 33% of the Nordic oat accessions at PGRC. The field assessment method detected fewer (75%) distinct accessions than the descriptor assessment (84%), when considering all accessions identified as distinct as 100%. Repeatability between years was higher in the field assessment (70%) than in the descriptor assessment (64%). The field assessment requires an experienced germplasm evaluator, but allows for handling large numbers of germplasm accessions and for detecting functional, fitness related, and user-relevant diversity. Combining field assessment with descriptor assessment and more sophisticated methods on selected subgroups may be the most efficient method for determination of internal duplication in genebank collections. Bulking phenotypically similar accessions within duplication groups is preferable to eliminating duplicate accessions when collection rationalization is required, as it reduces the risk of loosing diversity.

Progress in assessing the impact of Fusarium head blight on oat in western Canada and screening of avena germplasm for resistance

Fusarium head blight (FHB) of oat in western Canada was determined to be caused by a complex of Fusarium species, the composition and proportions of which varied considerably among years, and between Manitoba and Saskatchewan, the two main oat production regions (provinces) in western Canada. The levels of deoxynivalenol (DON), associated with Fusarium graminearum infection, were considerably higher in oat than in wheat and especially in barley, when levels of DON were compared to those of F. graminearum on seed, suggesting that oat may stimulate production of the mycotoxin by this causal species during the infection process, compared to that in other cereals. Testing of oat cultivars and lines for reaction to FHB indicated that while differences existed, these were relatively small. ‘Naked’ oats, in general, were more resistant. Several of the exotic oat accessions tested appeared to have superior levels of resistance and these are being used as parents in crosses to improve resistance in adapted, high q...

Analysis of Oil Composition in Cultivars and Wild Species of Oat (Avena sp.)

Oil quality and content were analyzed in 33 accessions from 13 wild species and 10 accessions of cultivated oat. Wild oat species tended to have higher oil and 18:1 fatty acid (FA) contents and lower amounts of 18:2 and 18:3 FAs as compared to cultivated oats. In addition to common FAs, minor amounts of several hydroxy and epoxy FAs were also present in the oat oil and mainly confined to specific lipid classes. These unusual FAs included the previously reported 15-hydroxy 18:2 (Delta9,12) (avenoleic acid) mostly found among polar lipids and a novel 7-hydroxyhexadecanoic acid located to 1,2-diacylglycerol. The present study highlights the potential of making use of the existing germplasm, consisting of wild oat species, in breeding programs for achieving new oat varieties that produce a range of oils with different FA compositions as well as having high oil contents. However, in one matter, oats apparently lack genetic diversity and that is for oil qualities that are highly enriched in the omega 3 (omega-3) FA 18:3. Consequently, developing oat cultivars with highly unsaturated oils will need involvement of other techniques such as biotechnology.

Genetic resources of barley and oat characterised by microsatellites

Barley (&lt;i&gt;Hordeum vulgare&lt;/i&gt; L.) and oat (&lt;i&gt;Avena sativa&lt;/i&gt; L.) are important crop species. 1865 accessions of winter barley, 2707 accessions of spring barley and 1998 accessions of oat are maintained in RICP Gene bank. The expert core collection is used to be established as a tool for germplasm study, conservation of genetic variability and for the identification of useful genes. The main aim of this study was to evaluate genetic diversity of barley and oat genotypes within the expert core collections. Genetic variation of 176 barley accessions was analyzed using 26 microsatellite loci, covering all 6 chromosomes. 330 oat accessions were analyzed using 26 microsatellite loci that are mapped only into linkage groups. For 26 barley microsatellite loci, 328 alleles were detected. The average number of alleles per locus was 12.6. In oat, for 26 oat microsatellite loci, 353 alleles were detected. The average number of alleles per locus was 13.6. The average DI (diversity index) was 0.11 in barley and 0.09 in oat. Dendrogram and PCA (Principal Component Analysis) based on microsatellite data showed a different influence of the place of origin, age of variety and pedigree on grouping into clusters. PCA showed that the breeding process had a negative impact on the level of genetic diversity and therefore there is a necessity of barley and oat germplasm conservation.

Assessments of genetic diversity within a world collection of cultivated hexaploid oat (Avena sativa L.) based on qualitative morphological characters

A characterization of 10,105 accessions of hexaploid cultivated oat (Avena sativa L. sensu lato) from 85 countries of the Plant Gene Resources of Canada (PGRC) collection was conducted at Saskatoon, Saskatchewan, Canada. Eight environmentally stable morphological characters (panicle type, panicle erectness, panicle density, lemma colour, dorsal awn of lemma, ligula, major infraspecific group), differentiated into 18 character states, were used to define genetically distinct morphological groups. Comparisons of oat diversity from different countries, among the major infraspecific groups and among Canadian oat cultivars registered between 1886 and 2002 were possible. The 10,105 accessions represented 118 different morphological groups. The number of accessions in each morphological group was unevenly distributed with the 13 most frequent morphological groups including 90% of the accessions. The most frequent morphological groups in the PGRC collection were identical with the most frequent types of Canadian oat cultivars. The greatest richness of diversity was found in oat from countries with temperate climates and intensive oat breeding programmes. The oat accessions comprised 8,754 accessions of common hulled oat, 183 accessions of hull-less oat and 1,168 accessions of red oat. For red oat (A. byzantina C. Koch), West Asia was richest in diversity. The USA could be considered a secondary centre of diversity for red oat and Canada a secondary centre of diversity for hull-less oat. Morphological diversity of oat cultivars released in Canada increased during the twentieth century. The morphological groups were related to formal taxonomical infraspecific classifications of A. sativa. Applications of the concept of defining morphological groups for phenotyping a large germplasm collection are demonstrated discussed.

On evolutionary pathways of Avena species

This article presents literary review and results analysis of evaluation of representative set of oat accessions of all Avena L. species. Results of complex study of major morphological characters and utilization of the karyotype structure data confirmed by the results of RAPD and avenin spectrum analysis are presented. Relationships of genomes of different Avena species at each ploidy level are discussed. Two genomes form the base of all Avena species, namely the A and C genomes. Results of the evaluation of several characteristics of the oat species and their geographical distribution are analysed. Probable evolutionary pathway of Avena species are suggested. Most likely the centres of origin of genus Avena L. are determined.

Patterns of AFLP variation in a core subset of cultivated hexaploid oat germplasm

Many core collections have been developed from large collections of crop germplasm, but most of these have not been characterized, particularly using molecular techniques, for germplasm management and utilization. We have attempted to characterize a structured sample representing a world collection of 11,622 cultivated hexaploid oat accessions in the hope of understanding the genetic structure of the world collection. The amplified fragment length polymorphism (AFLP) technique was applied to screen 670 accessions representing 79 countries and one group of uncertain origin. For each accession, 170 AFLP polymorphic bands detected by five AFLP primer pairs were scored. Analyses of the AFLP data showed the effectiveness of the stratified sampling applied in capturing country-wise AFLP variation. The frequencies of polymorphic bands ranged from 0.11 to 0.99, with an average of 0.72. The majority (89.9%) of the AFLP variation resided within accessions of each country, and only 6.2% of the AFLP differences existed among accessions of major geographic regions. Accessions from the Mediterranean region were the most distinct, while those from Russia and the USA were the most diverse. The two distinct groups that were observed were separated largely on the basis of common oat and red oat. Red oat was genetically more diverse than its common and hull-less counterparts, and hull-less oat was more related to common oat than red oat. Landrace and non-landrace accessions displayed similar AFLP variation patterns. These patterns are significant for understanding the domestication of cultivated oat and are useful in classifying the intraspecific diversity of oat germplasm, developing specific core subsets of the oat collection, and exploring new sources of genes for oat improvement.

Genetic Variation Within Chinese and Western Cultivated Oat Accessions

Oat (Avena sativa L.) have been cultivated in China for approximately 2000 years. Little is known about the origin of Chinese oat, and Western access to this germplasm pool has been limited. The objective of this research was to compare the relative levels of genetic diversity in a sample of 119 Chinese hulled and hull-less accessions with a sample of 33 hulled Western A. sativa and A. byzantina C. Koch accessions using RAPD analysis. Seventy-two polymorphic fragments were amplified by 18 primers in the Chinese and Western accessions. The Chinese germplasm pool exhibited a lower level of diversity than the Western germplasm pool. Sixty-seven polymophic fragments were detected in Western germplasm versus 49 in Chinese germplasm. The polymorphic index for Chinese germplasm was one-half that observed for Western germplasm, and the probability of observing a phenotype in Chinese germplasm that was not present in Western germplasm was one- tenth the reciprocal probability. A 152 × 152 relationship matrix of all pairwise combinations of the Chinese and Western accessions was constructed based on Jaccard’s distance estimates. The results suggested that the Chinese accessions, especially the hulled types, had a greater affinity with the nineteenth century A. sativa germplasm pool of northern and central Europe than with recent North American spring- and fall- sown cultivars, or the A. byzantina cultivars of Mediterranean origin.

Bulking generated considerable bias in detection of amplified fragment length polymorphism variations in oat, fringed brome and smooth bromegrass

AbstractAmplified fragment length polymorphism (AFLP) variations in bulk and plant‐by‐plant (PBP) samples of five oat (Avena sativa L.) accessions, one fringed brome (Bromus ciliatus L.) accession and two smooth bromegrass (B. inermis Leyss.) accessions were compared. The proportions of AFLP bands detected in PBP, but lost in bulk, samples of oat, fringed brome, and smooth bromegrass ranged from 19 to 31%, 40 to 44%, and 22 to 33% of the total bands scored, respectively. These lost bands had occurred at frequencies ranging from 0.1 to 1 in the PBP samples. These findings demonstrate bulking can generate substantial bias in detection of AFLP variations.

Identification of Quantitative Trait Loci for Resistance to Crown Rust in Oat Line MAM17-5

Crown rust, caused by the fungus Puccinia coronata Cda. f. sp. avenae Eriksson, is the most damaging disease of oat (Avena sativa L.). Breeding for resistance to crown rust has been an efficient and economical means to control the disease. Most of the resistance genes in recently released oat cultivars have been introgressed from the hexaploid, wild oat species A. sterilis L. The number of effective resistance genes has been rapidly decreasing. Characterization and utilization of new resistance sources are needed to ensure adequate resistance in future oat cultivars. Crown rust resistance in diploid, wild oat accessions was transferred to the hexaploid, cultivated oat line MAM17-5. The objective of this study was to identify the number, position, and effect of quantitative trait loci (QTL) and digenic QTL epistasis controlling crown rust resistance in MAM17-5. A linkage map of 272 molcular markers was used for this analysis. Reaction type and rust severity data were collected on field-grown adult plants from 152 F5:6 recombinant inbred lines derived from the cross, ‘Ogle’/MAM17-5. Composite interval mapping was conducted to identify genomic regions associated with crown rust resistance. Overall, two QTL, Pcq1 on linkage group 28 and Pcq2 on 29, were consistently identified for crown rust resistance in different years. Pcq1 and Pcq2 explained 48.5 to 70.1% and 9.6 to 14.0%, respectively, of the total phenotypic variation for crown rust resistance. Significant digenic, epistatic interactions were detected for QTL controlling rust severity but not reaction type. Marker-assisted selection targeting the major QTL, Pcq1, should be useful for efficient selection of crown rust resistance.

Identification of Quantitative Trait Loci for Resistance to Crown Rust in Oat Line MAM17‐5

Crown rust, caused by the fungus Puccinia coronata Cda. f. sp. avenae Eriksson, is the most damaging disease of oat (Avena sativa L.). Breeding for resistance to crown rust has been an efficient and economical means to control the disease. Most of the resistance genes in recently released oat cultivars have been introgressed from the hexaploid, wild oat species A. sterilis L. The number of effective resistance genes has been rapidly decreasing. Characterization and utilization of new resistance sources are needed to ensure adequate resistance in future oat cultivars. Crown rust resistance in diploid, wild oat accessions was transferred to the hexaploid, cultivated oat line MAM17‐5. The objective of this study was to identify the number, position, and effect of quantitative trait loci (QTL) and digenic QTL epistasis controlling crown rust resistance in MAM17‐5. A linkage map of 272 molcular markers was used for this analysis. Reaction type and rust severity data were collected on field‐grown adult plants from 152 F5:6 recombinant inbred lines derived from the cross, ‘Ogle’/MAM17‐5. Composite interval mapping was conducted to identify genomic regions associated with crown rust resistance. Overall, two QTL, Pcq1 on linkage group 28 and Pcq2 on 29, were consistently identified for crown rust resistance in different years. Pcq1 and Pcq2 explained 48.5 to 70.1% and 9.6 to 14.0%, respectively, of the total phenotypic variation for crown rust resistance. Significant digenic, epistatic interactions were detected for QTL controlling rust severity but not reaction type. Marker‐assisted selection targeting the major QTL, Pcq1, should be useful for efficient selection of crown rust resistance.