Two bacterial strains, Serratia fonticola ART-8 and Pseudomonas putida ART-9, were isolated from soil sown with rye in a monoculture. Although the S. fonticola strain produced more chitinase than the P. putida strain, P. putida produced more cellulase, lipase, HCN, and fluorescent siderophores. P. putida also solubilized more phosphate, and was the only strain to produce pyoverdine. Neither bacteria produced indoleacetic acid (IAA), nor did they produce siderophores on the CAS medium. Neither of the strains was highly effective at inhibiting Fusarium culmorum (~5%) or F. oxysporum (~24%). Wheat plants inoculated with these bacterial strains had higher (5.7-10.0%) thousand kernel weight and there appeared to be a positive association between thousand kernel weight and ear length.
The Fusarium graminearum species complex (FGSC) consists of phylogenetically distinct pathogenic species. Isolates from various regions display genetic variety worldwide. Three type B trichothecene chemotypes have been identified within the FGSC: nivalenol, 3-deoxynivalenol and 15-deoxynivalenol. The variations in morphological, genetic and virulence traits of FGSC fungi can be attributed mainly to their geographic boundaries. The geographic range of host plants, type of farming system and weather conditions also influence the prevalence of FGSC taxa. The geographic distribution of FGSC members may reflect not only their chemotype but also adaptive traits. While 15-acetyl-deoxynivalenol (15-ADON) chemotype is prevalent in most of Europe, the 3-acetyl-deoxynivalenol (3-ADON) chemotype has achieved greater prevalence in parts of North America. The Asian species F. asiaticum has spread into new territories. Isolates of F. asiaticum have been identified in North America and Europe, and the species has recently been reported to be infecting cereal crops in South America. The occurrence of numerous members of the FGSC in those regions and the introduction of F. asiaticum into new areas raise significant food safety concerns and indicate the need for monitoring mycotoxin concentrations in harvested grain.
3
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
Fungi diseases are the most serious threat to winter wheat crops in Poland causing losses of yield of up to 25%. Weather factors affect the types and intensity of disease outbreaks. The paper contains analysis of the impact of pre-onset as well as contemporaneous weather conditions such as temperature (both average and max/min), rainfall, and relative humidity on the frequency of infections caused by following pathogens: powdery mildew (Erysiph e graminis), septoria blotch (Mycosphaerella graminicola st. kon. Septoria tritici), glume blotch (Phaeosphaeria nodorum st. kon. Stagnospora nodorum , syn. Septoria nodorum), brown rust (Puccinia recondita f. sp. tritici), eyespot (Pseudocercosporella herpotrichoides), foot rot (Fusarium spp. and other). Several multiple stepwise (Backward Removal Method) regression models were estimated using linear functional form to examine how weather factors impact the wheat crop vulnerability to those pathogens. The results of this study contribute to our ability to forecast the magnitude and characteristics of disease outbreaks in the future based on observed meteorological data, thus enabling us to take optimal protective measures.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.