Screening of Oat Accessions for Fusarium Head Blight Resistance Using Spawn‐Inoculated Field Experiments

Abstract

Use of resistant cultivars is one of the most important measures to reduce the risk of Fusarium head blight (FHB, caused by various Fusarium spp.) and mycotoxins in cereals. Research on resistance to FHB has mainly focused on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) and is very limited in oat (Avena sativa L.). In Norway, routine testing of cultivars and breeding lines has been performed in spawn‐inoculated field experiments with Fusarium graminearum Schwabe as part of a concerted research and breeding effort to improve FHB resistance in oat. Data on FHB symptom, days to flowering, and plant height have been collected during the field seasons. Together with the field data, deoxynivalenol (DON) content and germination capacity of harvested kernels are used to score resistance levels of genotypes. In this paper, results are presented from a combined analysis of data from 9 yr of field trials from 2008 to 2016. Consistent and highly significant differences in DON content and germination capacity were documented among the current oat cultivars on the Norwegian market. These two negatively correlated parameters are used as selection criteria in breeding since they are relevant for the different end uses of the grains: DON content for use as food and feed, and germination capacity for seed production. In the paper, we discuss the pros and cons of the various screening methods and parameters used in assessing FHB resistance in oat and present the progress made in resistance breeding based on an established field testing methodology.

Resistance against Fusarium head blight in oats

“…In our study, VSS was reliably evaluated in all years only 14 days after inoculation, and we found it difficult to assess these symptoms in oats in comparison with wheat. This finding is in agreement with other studies on oats resistance (Tekauz et al, 2008;Gagkaeva et al, 2011), because at later developmental stages it becomes difficult to differentiate between natural senescence and FHB symptoms (Tekle et al, 2018). Severe symptoms attributed to Fusarium infections in oats are generally rare, and these are mainly observed in Northern Europe (Tekle et al, 2013).…”

“…In the present study, we found no significant correlation between plant Table 3). The effect of passive resistance mechanisms apparently depends on the genotypes tested and also on inoculum pressure and environmental conditions that determine disease development on plants (Tekle et al, 2018).…”

“…Tekle et al (2012) have reported that oats are most susceptible to Fusarium infection during anthesis and that this susceptibility decreases as plants develop and mature. The duration of the risky flowering period is longer in oats compared with wheat and barley (Tekle et al, 2018). It has been demonstrated that oats are susceptible to primary infection during anthesis.…”

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

“…Spawn-inoculated field experiments were carried out in 2015 at the Vollebekk research farm, Norwegian University of Life Sciences (59 • 39 N, 10 • 39 E), as previously described in [7]. The RIL from each cross were tested in two separate experiments using an alpha lattice experimental design with two replications sown early May.…”

“…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.…”