Non-pathogenic Fusarium oxysporum contributes in the biological suppression of pea wilt in disease suppressive soil

Peas are growing all over the world as a leguminous crop due to high nutrients value. Fusarium wilt of peas is a destructive disease and causing deleterious loses in pea growing regions of the world. The fields were surveyed with disease incidence of Fusarium wilt in major pea growing areas. Fields with heavy pathogen infestation and natural disease suppressive were observed at District Sahiwal, Pakistan. The samples were collected to diagnose the disease and factors responsible in the suppression of disease. The results of soil physio-chemical properties showed no significant differences between diseased and suppressive soils. Pathogenicity assays both in-vitro and pot trial showed that suppressive soil has natural ability to suppress the disease. Furthermore, in-vitro and pot assays were designed with different soil treatments to investigate the factors responsible in the natural disease suppressiveness in suppressive soil. The results demonstrated that the mechanism involved in disease suppressive soil is biotic in nature. All isolated fungal strains from diseased and healthy roots of pea were subjected to biological assays to evaluate the virulence. The assays showed that isolate SAH09 is non-pathogenic Fusarium oxysporum which was isolated from the pea roots of suppressive soil. Isolate SAH09 was used in dual culturing technique and pot trial to evaluate the mycoparastism behavior against virulent pathogenic isolates SAH03, SAH05 and SAH10. Results concluded that isolate SAH09 of non-pathogenic Fusarium oxysporum has potential to suppress the growth of all isolates of pathogenic Fusarium and possibly play the role in natural disease suppression in suppressive soils