Document Type : Research Paper
Authors
1
- M.Sc. of Plant Pathology Faculty of Agriculture, Vali-e-Asr University, Rafsanjan, Iran
2
Assistant Professor , Department of Plant Pathology, Faculty of Agriculture, Jiroft University, Jiroft Iran.
3
. Assistant Professor, Plant Protection Department, South Kerman Agricultural and Natural Resources Research and Education Center, AREEO, Jiroft, Iran
4
Plant Protection Research Department, South Kerman Agricultural and Natural Resources Research and Education Center, AREEO, Jiroft, Iran. , m.najafinia@areeo.ac.ir
5
Assistant Professor, Department of Agriculture, Payame Noor University, Tehran, Iran
6
Associate Professor, Department of Plant Pathology, Faculty of Agriculture, Vali-e-Asr University, Rafsanjan, Iran
10.22092/aj.2025.362441.1649
Abstract
Extended Abstract
Introduction:
Fusarium rot onion caused by Fusarium oxysporum is one of the most important onion diseases and is one of the main reasons for the reduction in yield of this product worldwide. In addition to the farm, this pathogen also damages the crop in the storage. The causal organism infects the basal stem plate of the bulb and eventually kills the entire plant through degradation of the basal plate. F. oxysporum infections in dormant bulbs during storage allow secondary infections to occur. Being Soilborne and its high host range has made it difficult to control. Biological control using antagonistic microorganisms is considered an alternative method for existing chemical treatments and a key component in the development of sustainable agriculture for suppressing phytopathogenicfungi. Arbuscular mycorrhizal fungi (AMF) are beneficial soil microorganisms establishing mutualistic symbioses with the roots of the most important food crops and playing key roles in the maintenance of long-term soil fertility and health. This study investigated the potential of the arbuscular mycorrhizal fungi (AMF) in both soil application and seed coating methods for the control of Fusarium onion rot and promotion of plant growth factors in lab and pot experiments.
Materials and Methods
Sampling:
First, sampling of onion fields in different areas of Jiroft city, which is one of the main onion growing areas in Iran, was done.
Isolation and Identification of Pathogens from Diseased Onion Plants:
After transferring infected plants to the laboratory, isolation and purification of fungi was done.
Pathogenicity test and selection of the most aggressive isolates:
After isolation and purification of isolates, and pathogenicity tests on seedlings and tubers, the most aggressive isolate was determined. Then the morphological identification of the harassed species based on the appearance characteristics using the identification keys of Nelson et al. (1983), Gerlach & Nirenberg (1982) and Leslie & Summerell (2008) was done.
Investigating the effect of mycorrhizae on fusarium rot disease of onion:
We evaluated the combined effect of four mycorrhizal species, Rhizophagus iranicus, R. intraradices, Funneliformis mosseae, and Glomus caledonium on Fusarium onion rot (the aggressive isolate) on a foreign hybrid cultivar (Minerva).
Staining and determination of root colonization percentage:
In order to prove the symbiotic relationship of arbuscular mycorrhizae with the roots of the selected plant species, the roots were stained according to the method of Phillips and Hayman (1970).
Pathogen inoculation and determination of disease severity percentage:
A six-point scale was used to evaluate the severity of the disease (Naseri, 2008).
Results & Discussion:
the most aggressive isolate was determined and after morphological and molecular studies, this isolate was identified as Fusarium oxysporum.
Root staining showed that: Evaluation of root mycorrhizal colonization indicated that these fungi had very good colonization in onion roots.
The results showed that the growth parameters increased significantly in the presence of mycorrhizal fungi. This was while the vegetative traits showed a decrease in the presence of fusarium contamination
Conclusion:
The most important goal of this research was to investigate the control effects of arbuscular mycorrhizal fungi on disease severity and growth indicators of onion plants. From the results of examining the severity of the disease in the treatments, it seems that mycorrhizal species are able to significantly control the fungus that causes this disease, F. oxyspurum.
Acknowledgements:
Thanks to Vali Asr University of Rafsanjan for permission to use the mycorrhizal collection in this research.
Keywords
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