Martin Koudela
Assistant Professor,Czech University of Life Sciences Prague, Czech Republic
Title: Effect of selected factors on growth of Fusarium oxysporum f. sp. conglutinans and evaluation of cabbage cultivar resistance to Fusarium wilt
Biography
Biography: Martin Koudela
Abstract
Statement of the Problem: Fusarium wilt is an important disease of cruciferous vegetables caused by soil phytopathogenic fungus Fusarium oxysporum f. sp. conglutinans (Foc). The dangerous character of the pathogen stems from its persistence in the soil and the ability to attack plants at any stage of its development. The aim was to evaluate the effect of temperature and pH on the development of Foc and assess differences between genotypes (breeding line and cultivar) linked with the sensitivity to Fusarium wilt.
Methodology & Theoretical Orientation: Temperature is one of the factors that can significantly influence the occurrence of Fusarium wilt. At temperatures below 17 °C, the rate of the disease is low and explaines a lower risk of the occurrence of the disease in the summer period. The optimum temperature and pH for the development of Foc disease are between 20-25 °C (some sources mentioning even a range of 24-29 °C) and pH 8, respectively. As the curative treatment by fungicides is not efficient, the effective protection against this disease remains a prevention consisting in the selection of a suitable cultivar(s) resistant to the disease. In the experiments conducted at the Czech Agriculture University Prague in 2017, the effect of temperature and pH on the growth of Foc mycelium was measured. The differences between breeding lines and cultivars concerning the sensitivity to Fusarium wilt after inoculation with Foc were determined. The visual symptoms of the attack by Foc were confirmed by PCR using specific markers.
Findings: The experiments documented that the most intense growth of Foc was observed at 24 °C. The intensity of Foc development under in vitro conditions corresponded to the intensity of the attack in a situation when the conventional growing substrate was used at a temperature of 24/22 °C and the attack by the fungus resulted in a higher mortality of plants. Using various pH values, small differences in the mycelial colony growth were found. The lowest growth rate of the phytopathogen was observed at pH 5. The sensitivity of a total of 37 varieties and lines of head cabbage against Foc were tested. The following lines were claimed to be resistant to Foc: DC6, MX11, SU2/15, SU10/15. On the other hand, the lines sensitive to Foc included: DS, DP25, HO2, RM.
Conclusion & Significance: Selection of the agrotechnical term with temperatures outside the optimum range for the growth of Foc can help eliminate the development of the phytopathogen to some extent. On the other hand, the regulation of soil pH is not an efficient tool to control the development of the pathogen since cruciferous vegetables require a much higher pH, compared to the pH values that inhibit the growth of Foc. Preliminary results suggested the existence of significant differences in resistance to Fusarium wilt between various breeding lines and cultivars.
The work was supported by the project NAZV QJ1510088 (Ministry of Agriculture of the Czech Republic).