Resistance of Chinese asters (Callistephus chinensis Nees.) to Fusarium wilts (Fusarium oxysporum f. sp. callistephi (Beach) Snyder and Hansen) evaluated using artificial inoculations

The resistance of Chinese asters to Fusarium wilt was tested by artificially inoculating the root systems. A mixture of Fusarium isolates was prepared with a concentration of about 104-109 propagules per litre of the pathogen. 63 cultivars of both domestic and foreign origin were evaluated in the 1st year, 95 in the 2nd year and 89 in the 3rd year. Clear, statistically valid differences in mortality, both with experiments involving artificial inoculations and considering natural infections, make it possible to divide aster varieties into three groups based in their resistance to infections. The first set can be described as resistant. This includes the Matsumoto, Einf. Madeleine and Americká kráska series, and several others. The second set can be described as being moderately resistant. This includes the Chryzantémokvěté and Standy series, and the cultivars Matsumoto Pink, Princes Armida and Jitka. The third set can be described as sensitive. This includes the Průhonický trpaslík, Jehlicovité and Pastel series and several others. A statistical analysis of the results shows that the Einf. Madeleine series of cultivars is the most resistant to Fusarium wilt. This series is phenotypically similar to the original botanical species. Resistance was evaluated by recording the differences in mortality rates between artificially-inoculated plants and non-inoculated group (controls).