Svampsamhällen och svampsjukdomar på åkerböna samt svamparnas inverkan på grobarheten

Abstract: Broad beans are becoming a larger crop in Sweden. This is probably due to the current discussion about the cultivation of soya beans that are imported to be used as protein fodder. Broad beans are a good break crop in a small grain intensive crop rotation and works as a protein source for animals together with for example ley. At present little research has been done on broad beans and more knowledge is needed. This study is about fungal communities and diseases on broad beans and the impact of these fungi on seed germination. Broad beans from 14 fields were collected and used during the study, ten from the county of Östergötland and four from the county of Västergötland.Fungi on harvested broad beans were identified by using terminal restriction fragment length polymorphism, (T-RFLP), where the internal transcribed spacer (ITS) region in the fungal DNA, which is unique for each species, is used. For identification of fungal species a reference library was prepared from the ITS sequences of pure isolations of fungi on the beans and the inserted fungal ITS sequences in cloned Escherichia coli bacteria. The ITS regions were sequenced and identified to species or genus level using BLASTN at GeneBank in order to use them as a reference library. The results from the T-RFLP were then compared with the reference library. The fungi that were identified on the broad beans with this method were Ascochyta fabae, Alternaria infectoria, Botrytis cinerea, Hypocrea viridescens, Arthrinum arundinis, Phoma exigua var. exigua, Penicillum aurantiogriseum, Mucor circinelloides, Lichtheimia corymbifera, Cladosporium sp, Fusarium sp., Alternaria sp., Ascochyta sp., and Chaetomium sp. Four of these fungi are plant pathogens, one is a yeast fungus and the rest are saprophytes. By cloning Ascochyta sp. and Cladosporium sp. were identified. Of the 14 fungi in the reference library, ten could be found on the bean samples. The species that were only found among the pure isolates and not on the bean samples were Mucor circinelloides, Lichtheimia corymbifera, Alternaria sp. and Fusarium sp.A germination test showed that the germination rate was between 89-99 % for each field sample. The sample with the lowest percentage also had the highest number of identified fungi on the beans. This shows that the fungi may have an impact on the germination on broad beans.