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Growth and sporulation of 20 single-spore isolates of Drechslera avenae grown on different agar media were investigated at 24oC and 11oC. Four different agar media were used – water agar (WA, 20 g agar x l-1), maltose-peptone agar (MPA, 20 g maltose from Difco, 2.5 g peptone, 20 g agar x l-1), potatodextrose agar (PDA, from Difco, 39 g x l-1), and rye agar (RA). The isolates were evaluated in respect of growth, colony colour, and formation of morphological structures. The study showed differences between isolates in respect of colony growth, depending on culture conditions. Comparing macroscopic features of all D. avenae isolates tested, three groups of strains formed equal colonies and four individual strains were separated. Generally, most strains, except strains number: 2, 4, 7, 9, 10, 13 and 17, grew faster on all agar media at 24oC than at 11oC. In case of D. avenae isolates, hyphal growth was the fastest on MPA medium and the slowest on WA. All strains investigated produced typical conidiophores and conidia both at 24oC and 11oC, but at 24oC earlier sporulation was observed. MPA and RA were the best media for the sporulation of D. avenae strains. Sporulation of this species was the latest on WA.
In Poland, cultivars belonging to three species of Tagetes are grown: T. erecta, T. patula, T. tenuifolia. Presented studies were conducted in 2015 in two localities of the Lublin region. Those studies included cultivars of Tagetes spp.: T. erecta (cv. ‘Alaska’, ‘Hawaii’, ‘Mann Im Mond’), T. patula (cv. ‘Bolero’ and ‘Carmen’) and T. tenuifolia (cv. ‘Lemon Gem’ and ‘Lulu’). Six weeks after the sowing and in flowering stage of analyzed marigold cultivars, the plants healthiness was assessed. The mean values of the disease index ranged from 16.25 to 29.0. The main cause of root infection at the seedling stage proved to be the species of Fusarium and Rhizoctonia solani. Proportion of plants with disease symptoms in flowering stage ranged from 1.25 to 5.5%. Regardless of the place of cultivation, species: A. alternata, F. culmorum and F. equiseti were the most often isolated from diseased plants in the flowering stage. Studies on the susceptibility of analyzed cultivars of marigold to infection by Fusarium culmorum, F. equiseti and F. sporotrichioides were conducted in a growth chamber. Significantly, the lowest value of the disease index of cultivar ‘Bolero’ (T. patula) allows to accept that cultivar as the least susceptible to infestation by Fusarium spp. under conditions of controlled temperature and humidity.
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. Mycological analysis showed that large numbers of Fusarium 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 F. culmorum, F. avenaceum, and F. solani. The investigation of the susceptibility of 15 oat genotypes to infection with two Fusarium graminearum strains – Tz 56 and Tk 235 – was carried out under growth chamber conditions at a temperature of 22–23oC and relative air humidity of 85%. The F. graminearum 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 F. graminearum 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.
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Fungi occurred on turfgrasses in lawn maintenance

51%
In recent years there has been an increasing interest in lawns and their appearance. Diseases affecting lawns, of which the causative agents can be various pathogens, reduce their quality. The study was conducted in two urban centers in the region of southeastern Poland – in the years 2006 and 2007 in Lublin and in 2007 in Zamość, both in sunny and in partly shaded places. The species composition of the grass sward and the severity of leaf infection were determined as well as mycological analysis of infected plants was carried out. In the case of the lawns in Lublin, the mean values of the disease indices for the leaves of the investigated turfgrasses were from 53.75 to 83.00 in the spring of 2006, while in spring of 2007 from 6.75 to 29.00. The mean values of the leaf disease indices determined in autumn of 2006 were from 16.00 to 86.25, whereas in autumn of 2007 from 4.50 to 21.25. The mean values of the disease indices for leaves of the turfgrasses studied in Zamość were from 24.50 to 48.25 in the spring of 2007, while in the autumn of that year they ranged from 28.00 to 54.75. Microdochium nivale was a great threat to turfgrasses in lawn culture in spring, whereas the cause of leaf spot of turfgrasses in the autumn were species B. sorokiniana and D. siccans. As far as the lawns in both cities are concerned, species of the genus Fusarium, in particular Fusarium culmorum, had a high percentage in root infection both in the spring and in the autumn.
One of the reasons lowering the esthetic appearance of a lawn are diseases caused by fungi. Studies were conducted on the sowing material of fifteen turfgrasses belonging to five species. Samples of seeds of the studied cultivars were from the harvest of 2007 and 2008. 573 fungi isolates belonging to 28 species and non-sporulating forms were obtained as a result of the mycological analysis during the two years of the experiment. In each year of studies, the greatest number of colonies belonging to Alternaria alternata. Within the group of pathogenic fungi: Fusarium culmorum, F. avenaceum, F. equiseti, F. solani, F. crookwellense, F. graminearum F. sporotrichioides, B. sorokiniana, D. siccans and Rhizoctonia solani were obtained. Studies on susceptibility of the seedlings of 8 cultivars of 4 grass species to infection by D. avenae No. 2, D. siccans No. 8 and B. sorokiniana No. 69 were conducted in a growth chamber. The statistical analysis of disease indexes for plants that grew in the experimental combination with artificial infection of the subsoil with above-mentioned strains as compared to the control indicated significant differences in all studied cultivars. Strain D. siccans No. 8 proved to be the most pathogenic towards cultivar Info of perennial ryegrass (92.20), and B. sorokiniana No. 69 towards wood bluegrass Pinokio cultivar (97.75). In the experimental combination with D. avenae the mean values of disease index ranged from 12.25 (Pinia) to 84.00 (Info).
Investigations were carried out in 1996 - 2000 in the Experimental Station of Cultivars Evaluation in Uhnin. Disease symptoms were recorded twice - in the seedling stage (18 in the Tottman's scale) and in milk ripe stage (77 in the Tottman's scale) of oat. The seedlings with root and sheath necrosis or plants with diseased stem base were obtained every year. The percentage of diseased seedlings ranged from 6.0 to 39.5, and percentage of older plants with necrotic stripes on lower intemodes ranged from 11.5 to 50.0. Results of mycological analysis of diseased plants showed that Fusarium spp., especially F. avenaceum and F. culmorum were isolated the most frequently, F. avenaceum was obtained in the seasons with different weather conditions. This indicates great tolerance of this fungus to temperature and humidity. In the seasons with high temperature F. culmorum was predominant. This species also can be tolerant to changing weather conditions. Warm and wet weather was favourable for oat infection by Bipolaris sorokiniana. Rhizoctonia solani was isolated from plants in milk ripe stage in each vegetation seasons, and from seedlings in years 1998 and 1999.
Field observations of oat panicles carried out in the fields of Danko Plant Breeding Company in the period 2006–2007 and in the fields of Strzelce Plant Breeding Company in 2008 showed the occurrence of panicles with Fusarium head blight symptoms in each growing season. In 2006 the percentage of such panicles ranged from 0.25 to 1.5%, in 2007 from 2.0 to 9.0%, whereas in 2008 from 0.5 to 8.0%. The species Fusarium poae was the main causal agent of Fusarium head blight. A study on inoculation of panicles of 12 genotypes of oats with Fusarium poae strain no. 35, which was conducted in 2008 in experimental fields near the city of Zamość, determined the number of kernels per panicle, grain yield from 40 panicles (4×10 panicles), and 1000-kernels weight (TKW) after the harvest of the crop at full grain maturity. Compared to the control, the lowest reduction in the number of kernels per panicle was found in the case of the cultivar ‘Krezus’ (88.69% of the control), while the highest one in ‘Szakal’ (22.46% of the control). As a result of inoculation of panicles with F. poae, the breeding line STH 8107 was characterized by the lowest decrease in kernels yield (69.76% of the control), whereas the highest decrease was found in the breeding line CHD 1430/02 (14.26% of the control). Compared to the control, the lowest reduction in TKW was observed in the breeding line STH 8107 (96.46% of the control), whereas the highest one in the breeding line CHD 1430/02 (45.06% of the control). The presence of secondary metabolites of F. poae and group A trichothecene compounds: HT-2 toxins (from 0 to 0.013 mg × kg-1), diacetoxyscirpenol (DAS) (from 0 to 0.002 mg × kg-1), T-2 tetraol (from 0.001 to 0.014 mg x g-1), and scirpentriol (from 0.008 to 0.074 mg × kg-1), was found in infected oat kernels. Group B trichothecenes: nivalenol (from 0 to 0.157 mg × g-1), deoxynivalenol (DON) (from 0 to 0.127 mg × kg-1) as well as its acetylated derivatives: 3-AcDON (from 0 to 0.059 mg × kg-1) and 15-Ac DON (from 0 to 0.288 mg × kg-1), were also present in oat kernels obtained from panicles artificially infected with Fusarium poae.
Drechslera leaf spot in the common oat (Avena sativa L.) is caused by D. avenae (syn. Pyrenophora chaetomioides, Helminthosporium avenae). Susceptibility of various oat cultivars and breeding lines to leaf infection by this pathogen was investigated in the field in 2001–2002 and in a growth chamber. After natural infection in the field, brown or brown-red spots caused by D. avenae were found in all oat genotypes and both years, but were less common in the drier and colder growing season (2001). Mean values of leaf infection index in the studied oat genotypes for the 2 years varied from 5.65 (CHD 2100) to 10.33 (Akt). After artificial inoculation in the growth chamber, symptoms were similar but leaf infection index was much higher – from 15.0 (Bajka) to 41.3 (STH 4699). High-performance liquid chromatography showed that anthraquinone derivatives produced by strain 1 of D. avenae include anthraquinone compaunds – cynodontin and helminthosporin. These compounds are known to limit the growth of some other pathogens and saprophytes.
One of the reasons lowering the esthetic appearance of a lawn are diseases caused by fungi. The study on seed material of 11 ornamental grass species was carried out in 2009 and 2010. 681 fungi isolates belonging to 22 species and non-sporulating forms were obtained over the two year study period. Among fungi pathogenic to grasses, species of the genus Fusarium were obtained especially in 2010. In that year, isolates of these fungi constituted 29.94% of all isolated colonies. Colonies of Alternaria alternata were also frequently isolated from the analyzed seed material of the ornamental grasses; in 2009 and 2010 its isolates accounted for respectively 25.36 and 12.57% of all isolates. The study on the health of ornamental grasses conducted in field conditions revealed the occurrence of plants with necrosis of the roots and lower stem internodes. The percentage of such plants ranged from 12% for Coix lacryma-jobi to 69% in the case of Festuca ovina. The mean values of the diseases indices were from 2.6 in the case of Coix lacrymajobi to 39.6 for Lagurus ovatus and they differed significantly. From the infected plants mainly species of genus Fusarium were obtained. Majority of isolates consisted F. oxysporum and also F. culmorum, F. crookwellense, F. graminearum, F. solani, F. avenaceum, F. sporotrichioides and species Bipolaris sorokiniana and Exserohilum pedicellatum were obtained. Studies on susceptibility of the seedlings of seven ornamental grass species to infection by Fusarium culmorum No. 34 and F. equiseti No. 62 were conducted in a growth chamber. The statistical analysis of disease indexes for plants that grew in the experimental combination with artificial infection of the subsoil with abovementioned strains as compared to the control indicated significant differences in all studied species in the case of F. culmorum and in 5 species in the experimental combination with F. equiseti. Strain Fusarium culmorum No. 34 proved to be the most pathogenic towards Festuca glauca (98.25), and F. equiseti No. 62 towards Phalaris canariensis (89.5).
This study was carried out in the period 2001-2005 in 10 winter rye plantations located in the Lublin region. The percentage of winter rye stems with necrosis symptoms on the lower internodes ranged from 32.5% to 71% in 2001, 38% to 68% in 2002, 21.5% to 56.5% in 2003, 35% to 70% in 2004, and 36% to 88% in 2005. The mean values of the disease index ranged from 7.5 to 46.75 and they differed significantly. The results of mycological analysis showed that the main pathogens infecting the roots and stem base of rye were the species Fusarium avenaceum (24% of all isolates) and F. culmorum (25% of all isolates).
Field inoculation experiments were performed during 2015–2017, in south-eastern part of Poland. The pathogenicity of F. crookwellense was estimated based on the kernels yield reduction of 10 selected oat genotypes. Panicles of oat were inoculated with conidial suspension of F. crookwellense strain No. 72 which caused a reduction in kernels yield by 28.54% and kernels number per panicle by 28.07%, compared to the control. The lowest yield reduction, as a result of the panicle inoculation with F. crookwellense, was found in the case of the cultivar ‘Pablo’ (18.73%), while the highest in the case of breeding line POB 961-1344/13 (36.4%) and cv. ‘Kozak’ (34.3%). Statistically the highest average yield reduction was observed in year 2016, when a higher amount of rainfall, especially in July (just after inoculation) and higher temperature, compared to the long-term standard, were observed. During the period between inoculation and harvest, F. crookwellense was able to produce nivalenol, fusarenone X and zearalenone in oat kernels at the average level of 0.065 mg∙kg⁻¹, 0.026 mg∙kg⁻¹ and 0.015 mg∙kg⁻¹ respectively.
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