Evaluating pathogenicity of some isolates of fusarium oxysporum was carried out under greenhouse conditions. Healthy cucumber transplants hybrid Sina1 was used. Results showed that all isolates of F. oxysporum were pathogenic to tested plants and caused wilt symptoms. Fusarium oxysporum (1) was the highly virulent and caused 100% wilt while Fusarium oxysporum (3) was the least pathogenic fungus with 62.5 % wilt.
Five conidial concentrations (1x103, 1x104, 1x105, 1x106 and 1x107cfu) of F. oxysporum were used to Studying the influence of inoculum densities on infection cucumber transplants hybrid Sina1. The obtained results revealed that inoculum density at 1x107 showed the highest percentage of dead plants 100 % followed by 1x106 which caused (85.42%) dead plants. On the other hand, inoculum densities of 1x103 and 1x104 caused the least percentage of dead plants 12.5 and 27.5 % respectively. Generally the dead plants were significantly increased by increasing inoculum densities.
The host range of F. oxysporum was studied. Six plant i.e. cucumbers, squashes, cantaloupe, luffas, melons and watermelons were inoculated with F. oxysporum. Results revealed that, all tested plants were not host plants for F. oxysporum fungus except cucumber plants, which were very susceptible to the fungus and showed 100% wilt symptoms.
Five cucumber hybrids namely Hisham, Db 162, Db 164, Al-Zaem and Sina1 were evaluated for the resistance to fusarium wilt under greenhouses conditions. The obtained results showed that percentage of infection varied among the different tested cucumber hybrids. The reaction of the tested cultivars could be divided into four different groups (high resistant, moderately resistant, susceptible and high susceptible).
Sina1 is high susceptible 95.83 % plants were infected. Al-Zaem 83.3% and Hisham 75.0% were susceptible. Db 162 (50.0%), was moderately resistant and Db 164 (16.67%) was high resistant. |
