Genetic variation and associations involving Fusarium head blight and deoxynivalenol accumulation in cultivated oat (Avena sativa L.)

Abstract

Resistance in oats (Avena sativa L.) to Fusarium graminearum was phenotyped in 424 spring oat lines from North America and Scandinavia and genotyped with 2974 SNP markers. Fusarium head blight (FHB), deoxynivalenol (DON) content, days to flowering (DTF) and days to yellow maturity (DTM) were scored in field trials in 2011–12. Trials with phenotypic ranges from 1 to 30 ppm, and sufficient accuracy were obtained by an augmented design and spawn inoculation. Discriminant analysis–PCA identified the different gene pools, with overlaps corresponding to known pedigrees and germplasm exchanges. Structure was negligible and GWAS (genomewide association study) was done using mixed linear models in TASSEL or partial least‐squares regression (PLSR). PLSR allows simultaneous analyses of several phenotypes (environments and/or traits) and is a promising tool for GWAS in plants and should be tested in species with sequenced genomes. FHB was associated with phenology QTLs, due to very susceptible early lines from the Midwest. Lines with consistently low DON (and early heading) were identified. Six QTLs for DON were not associated with earliness, including three QTLs reported previously.

Variation in Anther Extrusion and Its Impact on Fusarium Head Blight and Deoxynivalenol Content in Oat (Avena sativa L.)

“…Still, the correlations in oat appear weaker than in wheat, most likely due to the strong Type II resistance due to the pedicels in oat. Using selective phenotyping for high and low AE in wheat, like we did here in oat, genetic correlations between DON and AE increased to > 0.8 [5]. Thus, correlations will be expected to be weaker in random lines and crosses where the range in AE is limited.…”

“…This panel comprised 418 (mostly North American but some European) accessions previously analyzed for DON and FHB in 2011 and 2012 (for details, see [5]) using an un-replicated augmented design with 12 rows, 40 columns, and eight blocks, each containing the same set of two moderately resistant (Hurdal and Leggett) and four susceptible checks (Bessin, Gem, Ogle, and Horizon270). This gave eight independent values for each of the six checks.…”

“…However, in the past decade, the occurrence of mycotoxins in oat have received increasing attention, especially in the Nordic countries, where both shortage of certified seed due to reduced germination percentage and high toxin levels in harvested grains have been major issues. To overcome this, both the etiology of disease [4] and the resistance [5,6] have been studied. Breeding has reduced mycotoxin levels by 40% [7], but the mechanisms are not well understood.…”

Genome-wide Association Study and Genomic Prediction for Fusarium graminearum Resistance Traits in Nordic Oat (Avena sativa L.)

“…Worldwide, oat cultivation is concentrated to Russia, Canada, Australia, and Eastern and Northern Europe [2]. At least, in Finland [3,4], Norway [5][6][7][8], Russia [9], Sweden [10], Denmark [11], Germany [12,13], the UK [14,15], Canada [16][17][18] and the US [19], the occurrence of Fusarium head blight (FHB) in oats has been recorded. In most of the countries, deoxynivalenol (DON) is the predominant mycotoxin caused by Fusarium infection.…”

“…In European Union (EU) countries, legislation limits the use of unprocessed cereals with DON levels above 1250 µg/kg, unprocessed oat 1750 µg/kg and processed cereal foods 750 µg/kg [24]. In Norway, oat lots exceeding these limits are given a price penalty [8]. In Finland, oat lots for human consumption with toxin accumulation above the limits are discarded in the cereal trade.…”