Table 3. Morphological characters, morphometric data and temperature-growth relations on Carrot Agar of closely related Phytophthora species from Clade 6.
n.a., not available.
| P. crassamura | P. megasperma | P. ornamentata | P. mississippiae | P. gibbosa 1 | |
|---|---|---|---|---|---|
| Number of isolates examined | 5 | 4 | 4 | Yang et al. (2013) | Jung et al. (2011) |
| Sporangia | Ovoid, obpyriform, nonpapillate | Elongated, obpyriform, limoniform, nonpapillate | Ovoid, obpyriform, ellipsoid, nonpapillate | Ovoid, obpyriform, nonpapillate, some semipapillate | Ovoid, ellipsoid, nonpapillate, some semipapillate |
| Length x breath mean (μm) | 60.3 ± 6.0 × 37.4 ± 3.6 | 74.7 ± 9.5 × 32.0 ± 2.0 | 59.5 ± 6.2 × 36.8 ± 4.6 | 60.4 ± 6.0 × 31.3 ± 4.5 | 48.8 ± 9.6 × 30.8 ± 5.4 |
| Range of isolate means (μm) | 54.8–65.4 × 32.4–41.7 | 68.2–81.4 × 30.1–35.0 | 42.8–74.5 × 28.5–46.0 | 47.3–77.3 × 20.4–43.3 | 44.8–52.2 × 27.9–33.0 |
| Total range (μm) | 48.2–72.8 × 22.6–52.4 | 59.7–89.1 × 26.3–36.6 | 38.6–78.8 × 21.2–53.4 | n.a. | 24.8–71.1 × 17.4–48.0 |
| Length/breath ratio | 1.6 ± 0.1 | 2.3 ± 0.2 | 1.6 ± 0.1 | 1.96 | 1.58 ± 0.15 |
| Direct germination after 24-48h 2 | +++ | ++ | + | n.a. | n.a. |
| Proliferation | Internal nested and extended, external | Internal nested and extended, external | Internal nested and extended, never external | Internal nested and extended, external | Internal extended, external, never nested |
| Hyphal swellings | Globose, elongated, catenulate | Globose, elongated, catenulate | Globose, elongated, catenulate | Globose, elongated, catenulate | Subglobose, elongated, never catenulate |
| Breeding system | Homothallic | Homothallic | Homothallic | Heterothallic | Homothallic |
| Oogonia | Smooth-walled | Smooth-walled | Ornamented | Ornamented | Ornamented, smooth |
| Mean diameter (μm) | 45.4 ± 2.8 | 41.9 ± 4.4 | 34.2 ± 4.0 | 38.2 | 38.1 ± 5.4 |
| Range of isolate means (μm) | 43.8–47.1 | 39.8–43.5 | 31.8–38.1 | n.a. | 36.6–39.7 |
| Diameter range (μm) | 35.1–51.6 | 31.1–49.6 | 27.6–42.3 | n.a. | 27.0–49.9 |
| Oospores | Highly aplerotic | Slightly plerotic | Slightly aplerotic | Plerotic | Always aplerotic |
| Mean diameter (μm) | 38.2 ± 2.6 | 36.4 ± 4.0 | 34.2 ± 4.0 | 34.0 | 31.4 ± 4.6 |
| Diameter range (μm) | 27.8–44.8 | 25.2–46.9 | 26.8–43.4 | n.a. | 18.9–39.4 |
| Wall thickness (μm) | 4.8 ± 0.6 | 3.0 ± 0.9 | 4.3 ± 0.8 | n.a. | 3.17 ± 0.69 |
| Oospore wall index | 0.57 ± 0.04 | 0.41 ± 0.08 | 0.63 ± 0.08 | n.a. | 0.49 ± 0.06 |
| Abortion rate of isolates (%) | 26–44 | 12–25 | 13–22 | n.a. | 16–37 |
| Antheridia | Mostly paragynous | Mostly paragynous | Mostly paragynous | Amphigynous | Amphigynous |
| Length x breath mean (μm) | 12.5 ± 2.0 × 11.5 ± 1.5 | 12.6 ± 1.1 × 11.4 ± 0.7 | 15.7 ± 2.0 × 13.7 ± 2.6 | 19.5 × 14.3 | 13.6 ± 2.4 × 14.0 ± 2.0 |
| Total range (μm) | 8.3–15.8 × 7.6–13.9 | 8.2–15.6 × 7.8–13.6 | 10.6–19.8 × 9.3 ± 17.5 | n.a. | 10.6–24.9 × 7.6–17.8 |
| Maximum temperature (°C) | 32.5–< 35 | 30–32.5 | 32.5–< 35 | 35 | 32.5–< 35 |
| Optimum temperature (°C) | 25 | 25 | 25 | 25 | 30 |
| Growth rate at optimum (mm/day) | 7.1 ± 0.1 | 6.2 ± 0.1 | 6.0 ± 0.2 | n.a. | 6.3 ± 0.3 |
| Growth rate at 20°C (mm/day) | 5.8 ± 0.2 | 5.2 ± 0.1 | 5.0 ± 0.1 | n.a. | 5.2 ± 0.1 |
1Morphological characters and temperature-growth rates of Phytophthora gibbosa were examined on V8A.
2Presence of sporangia with direct germination: +++, abundant; ++, frequent; +, occasional.