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Acta Agrobotanica
|
2005
|
tom 58
|
nr 2
347-358
The objective of the study was to compare health status of harvested grain of spring barley cv. Rudzik, Rodos, Start and Maresi cultivated in organic system and cv. Damazy grown in an organic farm. Analyses showed that prevalent pathogen on grain was Bipolaris sorokiniana isolated from 48% of grains. Fungi from genus of Fusarium were obtained less numerously, from 27% of grains and were represented mainly by F. poae and F. avenaceum. Microscopic analysis of F. poae was confirmed by PCR analysis. All cultivars were intensively diseased by B. sorokiniana, thus it is impossible to show a cultivar especially recommended for this system, where B. sorokiniana can be serious problem. However cv. Damazy showed relatively the lowest infestation by B. sorokiniana and it also was not more intensively diseased by Fusarium spp. It is very important in nutrition aspect because these fungi can be dangerous for both human and animal health due to their abilities to produce mycotoxins.
Stem base health of spring barley cultivated under organic, integrated and conventional systems and fungal communities were studied. A worst plant health status was observed in the organic system. The macroscopic and subsequent mycological analyses revealed the occurrence of Bipolaris sorokiniana and Fusarium spp. The incidence of B. sorokiniana on stem bases was clearly dependent on a farming system, and the highest incidence of this pathogen was observed in the organic system. Also, in that system, Fusarium spp. were isolated more numerously in the beginning of tillering, but in dough stage B. sorokiniana was the most prevalent pathogen, and Fusarium spp. were more numerous in integrated and conventional systems. It is worth to note that organic conditions could be favourable to Gliocladium spp. Because of growing interest in ecology, excluding the use of pesticides and increasing popularity of biological disease control, these antagonistic fungi could be useful in organic systems.
Fusarium culmorum is an etiologic agent of barley foot rot. The identification and variability evaluation of F. culmorum isolates, originating from roots and stem bases of spring barley, was carried out using molecular methods. Species-specific SCAR primers were successfully applied to identify F. culmorum isolates from northern and south-eastern Poland. To determine DNA polymorphism on intraspecies level RAPD technique was used. Twenty three RAPD markers revealed DNA polymorphism suitable to assess genetic variation among isolates examined. Cluster analysis of RAPD data identified a few groups of isolates. In some cases grouping of isolates was correlated with their geographic origin.
Celem prowadzonych badań w latach 1997, 1998 i 2000 badań było określe­nie występowania Rhizoctonia solani na kiełkach, łodygach i bulwach oraz Streptomyces scabies i Fusarium spp. na bulwach ziemniaka uprawianego w systemie ekologicznym i konwencjonalnym. Stwierdzono, że w każdym roku nasilenie tych patogenów było stosunkowo duże. Jednak porażenie kiełków, pędów i bulw w okresie 3 lat w obu sposobach uprawy było na podobnym poziomie, a w jednym roku nawet wyższe w systemie ekologicznym. Świadczyć to może o braku mecha­nizmów obronnych w glebie tego systemu przed badanymi patogenami ziemnia­ka. Nie potwierdziły się powszechnie panujące przypuszczenia, że zaniechanie stosowania nawozów mineralnych i pestycydów wpływa korzystnie na rozwój sap­rofitycznych mikroorganizmów, które ewentualnie mogą zmniejszyć zagrożenie porażenia roślin przez gatunki patogeniczne.
The researched material was healthiness of roots and fungus composition of spring barley cultivated under organic, integrated and conventional farming systems. The studies were carried out in 1998-2001 on experimental fields in Osiny near Puławy, south-eastern Poland. In the emergence stage the roots health status was the lowest in organic system however in the end of vegetation season, in dough maturity stage the most disease symptoms were stated in conventional system. The mycological analyses revealed the occurrence of two important pathogens: Bipolaris sorokiniana and Fusarium spp. Despite of root healthiness macroscopic analyses showed their lower health status in organic system only in emergence stage and the most quantity of plants with disease symptoms in dough maturity stage were observed in conventional system, but pathogens like Bipolaris sorokiniana and Fusarium spp. were mostly isolated in organic system in both phases. It can suggest that disease symptoms in conventional system can be caused by different than fungus factors. The lowest percent of mentioned pathogens was stated in integrated system. It is worth to notice that organic conditions could be favourable to Gliocladium roseum. Because of growing interest in ecology, giving up of using pesticides and more and more popular biological disease control, these fungi of Gliocladium genus were used in this system due to their antagonistic properties.
The identification concerned 71 isolates obtained from potato tubers which were identified on the basis of morphological features as Fusarium sambucinum, and 46 isolates from wheat, barley rye, triticale and potato. Which were identified as F. culmorum. Molecular analyses using SCARPCR revealed incorrect identification of 5 isolates obtained from potato: two were earlier identified as F. sambucinum and 3 as F. culmorum. This indicates the fact that F. culmorum and F. sambucinum occurring on potato can be mistaken while using a traditional microscopic identification. The research confirmed the usefulness of species-specific primers in diagnostics of plant pathogens. It was stated that for obtaining fully reliable results, it is advisable to use, besides a microscopic method, a molecular analysis.
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