Abstract

Fungi representing Alternaria spp. are ubiquitous pathogens that may under certain conditions cause spoilage of various food crops. Several Alternaria species are known producers of toxic secondary metabolites in some fruits and vegetables, nevertheless, only limited knowledge is available on the occurrence of these mycotoxins in legumes and/or oilseeds used for human nutrition. In the first part of the presented study, the analytical method employing reversed phase high-performance liquid chromatography (HPLC) coupled with fluorescence detection (FLD) was implemented to enable the examination of these food commodities for the presence of altenuene (AE), alternariol (AOH), and alternariol monomethyl ether (AME); the limits of detection were 1, 3 and 2 µg/kg for AE, AOH, and AME, respectively. Altogether 122 flax and 84 pea seed samples grown under organic and/or conventional farming conditions were analysed in the years 2002–2003. AME was detected in 20 flax seed samples; AE and AOH were present in only 2 and 4 samples, respectively. More frequent incidence of Alternaria toxins was recognised in fibre flax seeds as compared to linseed samples. Compared to the crops from the conventional farming, the concentrations of these mycotoxins found in positive organic samples were higher. No Alternaria mycotoxins were detected in the pea samples, probably due to the presence of antifungal compounds in the respective crop.  

The yield potential, quality and level of resistance to powdery mildew (Erysiphe pisi DC.) of afila smooth seeded pea (Pisum sativum L.) were tested in the field trials. The cultivars and breeding lines Mozart, Consort-R, AGT-01, Cebeco 1171 and AGT-GH surpassed the control cv. Gotik in the yields of dry seed, in contrast the dry seed yields of Highlight, AGT-KR, Melfort and LU 390-R2 were about 12-27% lower than that of the control. The low seed yield was caused by virus infections (PEMV, BYMV), root diseases (Pythium, Fusarium), and a low level of thousand seeds weight (TSW). Material crossing with donors possessing high yield potential, a higher TSW, and a higher tolerance to root diseases had a positive effect on the dry seed yield. The main objective of the resistant pea breeding programme is afila smooth seeded pea resistant to powdery mildew, with a high tolerance to viruses, root diseases, and lodging, with the stem length of 60 to 75 cm, and with high yield potential.

The spectrum of diseases and their harmfulness to caraway has changed within the past few years. The importance of <I>Mycocentrospora acerina</I>, recently regarded as the most serious pathogen, has decreased while the severity of other fungi, such as <I>Erysiphe heraclei</I> or <I>Ascochyta carv</I>i, has increased. This work was undertaken to identify and determine the incidence of fungi which contaminate the seeds and to evaluate the effect of fungicidal treatment. Direct microscopic evaluation confirmed that <I>Alternaria alternata</I> and <I>Cladosporium cladosporiodes</I> were the most common fungi occurring on caraway seeds. <I>Cladosporium herbarum, Fusarium avenaceum, F. culmorum, F. equiseti, Fusarium</I> sp.,<I> Epicoccum nigrum, Trichothecium roseum</I> and <I>Aureobasidium</I> sp. were not so frequent. In field trials during 2005 and 2006, fungicide application at flowering of the crop affected mainly the pathogenic fungi <I>Ascochyta carvi</I> and <I>Septoria carvi</I>, but not the saprophytic fungi <I>A. alternata</I> or <I>Cladosporium</I> sp. In comparison with the control, in 2005 the yield increased (*&alpha; = 0.05) only with prothioconazole and dimoxystrobin + boscalid. There was no yield increase at the significance level &alpha; = 0.01 in either year. The fungicides had only a very small effect on the weight of thousand seeds, the germination rate and the essential oil content. The results of the trials showed that most of the tested preparations would be perspective for use in practice, especially under weather conditions that are more favourable for a higher incidence of severe fungal diseases. Application of fungicides reduced the occurrence of the fungi and had no negative effect on yield parameters and quality.

The incidence of fungi on caraway (Carum carvi L.), fennel (Foeniculum vulgare Mill.), coriander (Coriandrum sativum L.) and anise (Pimpinella anisum L.) was observed on several localities in the Czech Republic. Incidence of 26 parasitic and saprophytic fungi were found on fennel, 35 species on coriander, 21 species on anise and 34 species on caraway. Small plot trials of spices were evaluated during the whole growing season. The fungicides in caraway were applied in different growth stages. The test results showed high effectiveness of autumn and early spring applications on the most dangerous pathogen of caraway – Mycocentrospora acerina. Three fungicides were tested in fennel field trials showing sufficient force against pathogenic fungus Cercosporidium punctum. The complex of root fungi causes the serious damage of coriander. Foliar application of fungicides did not present adequate effect. Four growth regulators were tested, but all of them increased incidence of fungi Fusarium sp. and Alternaria alternata.