The occurrence of Fusarium spp. on oat (Avena sativa L.) and susceptibility of seedlings of selected genotypes to infection with Fusarium graminearum Schwabe

Abstract

<p>The present study was carried out in the years 2010–2012 in the fields of the Strzelce Plant Breeding Company Ltd., belonging to the Plant Breeding and Acclimatization Institute in Radzików, and it included 39 oat genotypes. At the six-week seedling stage, the percentage of plants with root and leaf sheath necrosis symptoms was evaluated. In 2010 the percentage of seedlings with disease symptoms ranged from 6.5% to 25%, in 2011 it ranged from 17% to 34.5%, whereas in 2012 from 10% to 25%. In 2010 the disease index ranged from 1.4 to 5.7, in 2011 from 4.5 to 8.8, while in 2012 it was between 2.0 and 5.4.</p><p>Mycological analysis showed that large numbers of <em>Fusarium </em>spp. colonies were obtained both from the roots and leaf sheaths. Isolates of these fungi accounted for 63.48% of the total fungi isolated from seedlings. Seedlings grown under the conditions of central Poland were damaged by the species <em>F. culmorum</em>, <em>F. avenaceum, </em>and <em>F. solani</em>. The investigation of the susceptibility of 15 oat genotypes to infection with two <em>Fusarium graminearum </em>strains – Tz 56 and Tk 235 – was carried out under growth chamber conditions at a temperature of 22–23°C and relative air humidity of 85%. The <em>F. graminearum </em>strain Tz 56 proved to be the most pathogenic to seedlings of the breeding lines STH 0.9403 and POB 1316/08, for which the disease index was 80.5 and 75.5, respectively. The lowest pathogenicity of the a.m. strain was recorded in the case of the genotype DC 1832/05, for which the disease index was 26.5. The <em>F. graminearum </em>strain Tk 235 proved to be the most pathogenic to the genotypes STH 0.9403 and STH 0.9423, for which the disease index was 70.5 and 70.0, respectively, whereas this strain was least pathogenic to the breeding line DC 2112/05, in the case of which the disease index was 25.5.</p>