With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines....With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty two strains were further identified by Biolog, from which 133 were selected for fatty acid methyl ester (FAME) analysis together with 80 standard reference!strains. Sixteen species or types of Pseudomonas and 17 genera of non pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed were P. putida and P. fulva. About 17% of the strains of Pseudomonas and 2% of the non pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents.展开更多
Across all Russia global climate change is observed. Consequences of climatic changes, undoubtedly, will be reflected in distribution of harmful organisms, their injuriousness and will demand development of new approa...Across all Russia global climate change is observed. Consequences of climatic changes, undoubtedly, will be reflected in distribution of harmful organisms, their injuriousness and will demand development of new approaches in plant protection. Over the last 10 years, the spread of cereal crop diseases in the Northwest Russia has been monitored. The purpose of researches is to find new diseases in the Northwest region of Russia. Disease progression was mainly monitored 3 or 4 times during the growing season, from germination to crop maturity. As a result in this region the new diseases were found. In 2005-2007 the causal agent of yellow leaf spot Pyrenophora tritici-repentis was found on wheat. Fusarium graminearum historically has two areas in Russia： the North Caucasus and the Far East. However, since 2003 F. graminearum appeared on the territory of the North-West of Russia. Septoria tritici became the main pathogen of wheat in the North-Western Region.. In 2013 Ramularia collo-cygni was found in Arkhangelsk region. These observations suggest that global warming of climate leads to an expansion south species pathogen to the north regions of Russia.展开更多
Wheat ranks first among cereal crops cultivated in the world. In its production, diseases like powdery mildew, fusarium head blight and rusts caused by fungal pathogens represent a major problem. They produce differen...Wheat ranks first among cereal crops cultivated in the world. In its production, diseases like powdery mildew, fusarium head blight and rusts caused by fungal pathogens represent a major problem. They produce different symptoms that cause severe crop damage by infecting the spikes, leaves, roots, stems and grains. They are causing losses both by reducing the quantity of the harvested crop and the quality of the product. Quality problems of the harvested product can be due to shrivelled seed, which are frequently found as a consequence of the infection by leaf pathogens, such as mildews, rusts and Septoria. Fusarium head blight is the major culprit for mycotoxin contamination from the harvested grain, causing economic losses and in the worst casing human and animal health problems. In severe epidemics, all these fungal diseases can significantly reduce yield. Resistance to fungi is beneficial not only from a commercial point of view （yield）, but also because of the reduced levels of mycotoxins. The integration of transgenic approaches offers a potential chemical-free and environment-friendly solution for controlling fungal pathogens. This is an essential asset for wheat world food security.展开更多
文摘With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty two strains were further identified by Biolog, from which 133 were selected for fatty acid methyl ester (FAME) analysis together with 80 standard reference!strains. Sixteen species or types of Pseudomonas and 17 genera of non pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed were P. putida and P. fulva. About 17% of the strains of Pseudomonas and 2% of the non pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents.
文摘Across all Russia global climate change is observed. Consequences of climatic changes, undoubtedly, will be reflected in distribution of harmful organisms, their injuriousness and will demand development of new approaches in plant protection. Over the last 10 years, the spread of cereal crop diseases in the Northwest Russia has been monitored. The purpose of researches is to find new diseases in the Northwest region of Russia. Disease progression was mainly monitored 3 or 4 times during the growing season, from germination to crop maturity. As a result in this region the new diseases were found. In 2005-2007 the causal agent of yellow leaf spot Pyrenophora tritici-repentis was found on wheat. Fusarium graminearum historically has two areas in Russia： the North Caucasus and the Far East. However, since 2003 F. graminearum appeared on the territory of the North-West of Russia. Septoria tritici became the main pathogen of wheat in the North-Western Region.. In 2013 Ramularia collo-cygni was found in Arkhangelsk region. These observations suggest that global warming of climate leads to an expansion south species pathogen to the north regions of Russia.
文摘Wheat ranks first among cereal crops cultivated in the world. In its production, diseases like powdery mildew, fusarium head blight and rusts caused by fungal pathogens represent a major problem. They produce different symptoms that cause severe crop damage by infecting the spikes, leaves, roots, stems and grains. They are causing losses both by reducing the quantity of the harvested crop and the quality of the product. Quality problems of the harvested product can be due to shrivelled seed, which are frequently found as a consequence of the infection by leaf pathogens, such as mildews, rusts and Septoria. Fusarium head blight is the major culprit for mycotoxin contamination from the harvested grain, causing economic losses and in the worst casing human and animal health problems. In severe epidemics, all these fungal diseases can significantly reduce yield. Resistance to fungi is beneficial not only from a commercial point of view （yield）, but also because of the reduced levels of mycotoxins. The integration of transgenic approaches offers a potential chemical-free and environment-friendly solution for controlling fungal pathogens. This is an essential asset for wheat world food security.
