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Powdery Mildew (Blumeria Graminis F. Sp. Tritici) Infection and Amount of Key Defence Chemicals

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Powdery Mildew (Blumeria Graminis F. Sp. Tritici) Infection and Amount of Key Defence Chemicals Original scientific paper DOI: /10.5513/JCEA01/21.4.2655 Journal of Central European Agriculture, 2020, 21(4), p.741-750 Powdery mildew (Blumeria graminis f. sp. tritici) infection and amount of key defence chemicals - cyclic hydroxamic acids - of field cultivated wheat (Triticum aestivum L.) Lisztharmat (Blumeria graminis f. sp. tritici) fertőzöttség és a növényi védekezésben központi szerepet betöltő ciklikus hidroxámsavak mennyisége őszi búzában (Triticum aestivum L.) Péter MAKLEIT (✉), Lóránt SZŐKE, Szilvia VERES University of Debrecen, Faculty of Agricultural and Food Sciences and Environmental Management, Institute of Crop Sciences, H-4032 Debrecen, Böszörményi út 138, Hungary ✉ Corresponding author: [email protected] Received: 26 September, 2019; accepted: 31 May, 2020 ABSTRACT Cultivated wheat varieties have different degrees of resistance against powdery mildew. Cyclic hydroxamic acids are key defence chemicals of wheat. Examinations comprised the measurement of cyclic hydroxamic acid content and powdery mildew infection of three varieties (Lukullus, Lennox, Ispán) and a hybrid (Hystar) of field cultivated wheat, and the effectivity of two biological (Polyversum and Trifender) and one conventional fungicide (Sólyom) on powdery mildew. Sample collection and measurement of fungus infection were carried out on three occasions: at BBCH 23-24, BBCH 32-33 and BBCH 77-83 phenological phases. Variety/hybrid and sampling time has significant effect on cyclic hydroxamic acid content, but there was no direct correlation between hydroxamic acid content and powdery mildew infection. Differences were found amongst varieties/hybrid in powdery mildew infection too. Only the hybrid, Hystar, showed considerable infection at every sampling time. The conventional chemical out of fungicides alone proved to be effective, and its effectivity lasted for five weeks. Keywords: biotic stress, conventional and biological fungicides, defence chemicals ÖSSZEFOGLALÁS A termesztett őszi búza fajtáknak/hibrideknek eltérő lisztharmat fogékonysága van. A ciklikus hidroxámsavak az őszi búza károsítókkal szembeni védelmében központi szerepe töltenek be. Három őszi búza fajta (Lukullus, Lennox, Ispán) és egy hybrid (Hystar) ciklikus hidroxámsav-tartalmát és lisztharmat fertőzöttségét, valamint két biológiai (Polyversum and Trifender) és egy hagyományos gombaölő szer (Sólyom) lisztharmattal szembeni hatékonyságát vizsgáltuk szántóföldi körülmények között. A mintavételek és a lisztharmat fertőzöttség felmérése három fenológiai fázisban történt (BBCH 23-24; BBCH 32-33 és BBCH 77-83). A fajta/hybrid és a mintavétel időpontja szignifikánsan befolyásolta a ciklikus hidroxámsav-tartalmat, a lisztharmat fertőzöttség és a ciklikus hidroxámsav-tartalom között azonban nem volt megállapítható összefüggés. A fajták/hybrid között a lisztharmat fertőzöttség tekintetében szintén szignifikáns különbségeket figyeltünk meg. Kizárólag a Hystar hybrid mutatott mindhárom mintavételi időpontban számottevő fertőzöttséget. A gombaölő szerek közül csak a hagyományos, kémiai (Sólyom) bizonyult hatékonynak, öt hét tartamhatással. Kulcsszavak: biotikus stress, hagyományos és biológiai gombaölő szerek, vegyületek az önvédelemben 741 Original scientific paper DOI: /10.5513/JCEA01/21.4.2655 Makleit et al.: Powdery mildew (Blumeria graminis f. sp. tritici) infection and amount of key... INTRODUCTION of ammonium-nitrate were used on the two respective occasions. In April a micronutrients solution was sprayed The sowing area of wheat (Tricum aestivum L.) in (Omex – 2 liters/ha and Epsom salt (7 kilograms / Hungary in 2018 was almost 1 million hectares (Central hectare) were applied. On 24th April Gramma Extra (20 Bureau of Statistics, Hungary). Powdery mildew infects grams/hectare) and Mecomorn 750 SL (1 liter/hectare) wheat regularly, on 60-90% of the cultivated area, herbicides were sprayed. At the end of May, King resulting in a loss of crop of 5-25% (Horváth, 1995). 10EC (0.1 liter/hectare) insectiside was applied against Cyclic hydroxamic acids are self-protecting chemicals Oulema melanopus. The experimental treatments in three of most Poaceae family plants, like wheat, maize and rye repetitions were as follows: Trifender Pro (0.5 kilogram/ (Niemeyer, 1988; 2009). The correlation between their hectare), Polyversum (1.0 kilogram/hectare) and Sólyom quantity and plant disease susceptibility has been proved (0.6 liter/hectare). Plots without any treatment served in several cases (Niemeyer, 1988; Nakagawa et al., 1995; as control. Plots were 12 meters wide. There was no Zheng et al., 2005). There are scarce data in connection additional fungicide treatment in the experimental field. with the effects of cyclic hydroxamic acids on powdery Treatments were carried out on 11th April. At that time mildew susceptibility (Brandes and Heitefuss, 1971; the temperature was 15 degree celsius and the sky was Zheng et al., 2005). The purpose of the examinations cloudy. Polyversum, a biological fungicide, contains the were the determination of cyclic hydroxamic acid content fungus Pythium oligandrum, which parasitizes several in different phenological phases and the evaluation of pathogen fungi and stimulates the plants’ self-defence. powdery mildew infection of various field cultivated Trifender Pro includes the Trichoderma asperellum T34 wheat varieties. The examinations covered the evaluation strain, an antibiotics producing fungus-parasite. The of biological and conventional fungicides’ effectiveness specific feature of this experiment is the foliar application on powdery mildew and the effect of their application on of this plant stimulator. Sólyom is a traditional chemical cyclic hydroxamic acid content. fungicide with tebuconazole, triadimenol and spiroxamine active ingredients. MATERIALS AND METHODS Settling of the experiment, agricultural techniques Sample collection The experiment was set up on the fields of „Kurucz The first sampling was fulfilled 7 days after Farm Kft.”, near the parish of Ebes, which is located in experimental treatments, on 18th April, at BBCH 23-24, the north-east of Hungary. The area of the experimental with the second carried out on 16th May at BBCH 32- field was 11.22 hectares. Its soil is chernozem, with 33 and the third sampling performed on 14th June at considerable lime content with a flat and smooth surface. BBCH 77-83 phenological phase. At the first sampling After the harvesting of sunflower, the preceding crop, the youngest emerged leaf of the main shoot, at the 20 tons/hectare organic manure was used for basic second sampling the third emerged leaf on the main nutrition. After manure application, disc tiller was used. shoot (the still infected leaf on the highest level of the A cultivator was used to prepare the soil before sowing. shoots), and at the third sampling the flag leaf were Sowing was performed on the 1st of November 2017, selected for sampling. At first sampling, 10 samples were with special attention to the moisture content of the soil. collected per treatment, varieties/hybrid and repetitions, Three varieties and one hybrid were sowed (Lukullus, which amounts to 480 samples (4 varieties/hybrid x 4 Lennox, Ispán and Hystar) at right angles to the border of treatments x 3 repetitions x 10 samples). At second and the field, in two sowing-machine widths, in 300 m long third samplings, 8 samples were collected per treatment, distance rows. Additional fertilizations were performed varieties/hybrid and repetitions in each, providing us in February and in April. 100 and 150 kilograms/hectare 384 samples for each sampling. Altogether 1248 samples 742 Original scientific paper DOI: /10.5513/JCEA01/21.4.2655 Makleit et al.: Powdery mildew (Blumeria graminis f. sp. tritici) infection and amount of key... were cut out and prepared lately. Samples at the time of light/dark regime 10/14 h at 24/20°C, relative humidity sampling were temporarily stored in freezer bags. Until of 65–70% and a photosynthetic photon flux of 390 m processing, samples were stored at minus 80 centigrade E/m2/s. in the lab. Statistical analysis methods Evaluation of powdery mildew infection Statistical analyses were performed by using SPSS The weather in early spring of 2018 was not favourable version 23.0. For normal distribution of data, t-test or for fungal diseases. Monitoring of fungal infection was analysis of variance were used. For determination of carried out twice in the spring, on 16th March and 5th homogenous subjects Duncan’s test was applied. Where April. Powdery mildew appearance was noticed on the data distribution was not normal, nonparametric tests second occasion. Other fungal diseases did not appear were appropriate. Correlation analyses were carried out in the growing season. Powdery mildew infection was by generating and evaluating scatter plots. evaluated by surveying 20, randomly chosen plants from each plot. Evaluation was made on the same day as sample RESULTS collection. At the first sampling, the ratio of infested Comparison of cyclic hydroxamic acid content of plants, at the second sampling the ratio of infected part varieties/hybrid of the sampled leaves, and at the third sampling the ratio Comparison of all experimental data by varieties/ of infected plants and the ratio of infected area on flag hybrid revealed that Lukullus and Lennox had lower and leaves were determined. As at the third sampling only equal (Lukullus: 180.72±4.39; Lennox: 183.00±4.34 mg/ Hystar’s flag leaves were infected, only Hystar’s infection kg fresh weight), Ispán and Hystar
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