Table 4.
Effect of VCs produced by diverse F. oxysporum strains on the secretion of antifungal metabolites by four Trichoderma spp.
| F. oxysporum strains | Relative colony diameter (%)a | |||
|---|---|---|---|---|
| T. virens | T. viride | T. harzianum | T. asperellum | |
| NRRL26379 | 30.7 ± 2.6 (d) | 55.8 ± 2.4 (b) | – | – |
| NRRL38499 | 56.9 ± 1.9 (a) | 25.7 ± 3.1 (e) | – | – |
| NRRL54003 | 35.0 ± 2.2 (c) | 24.8 ± 0.6 (e) | – | – |
| 9605 | 15.2 ± 3.8 (g) | no growth (g) | – | – |
| W61 | 19.6 ± 1.3 (f) | no growth (g) | – | – |
| NRRL38272 | 24.1 ± 2.6 (e) | no growth (g) | – | – |
| NRRL38487 | no growth (h) | 27.0 ± 1.7 (d) | 59.6 ± 3.1 (a) | – |
| NRRL37611 | 25.0 ± 2.1 (e) | no growth (g) | – | – |
| NRRL37616 | no growth (h) | 27.0 ± 2.1 (d) | 61.4 ± 2.0 (a) | – |
| NRRL26029 | no growth (h) | 3.0 ± 1.8 (f) | 59.9 ± 1.5 (a) | – |
| NRRL36118 | 17.9 ± 3.1 (g) | no growth (g) | – | – |
| NRRL22518 | 34.0 ± 1.0 (c) | 40.0 ± 2.5 (c) | – | – |
| NRRL22519 | 37.5 ± 2.1 (b) | 68.0 ± 2.9 (a) | – | – |
After exposure of individual Trichoderma strains to VCs from the listed F. oxysporum strains and Control (Trichoderma co-cultivated with un-inoculated PDA plate), F. oxysporum strain NRRL54003 was used to assess the degree of growth inhibition caused by secreted Trichoderma metabolites. Relative colony diameter (%) after each treatment was calculated using (Dtreatment/Dcontrol) × 100, where Dcontrol and Dtreatment indicated the colony diameters of F. oxysporum in control and VC treatments, respectively. Values shown correspond to the mean ± standard deviation (SD) of data from three replicates. Different letters indicate significant differences between treatments, according to Fisher's test at P = 0.05. – indicates no induction.