Four isolates of Sclerotinia sclerotiorum (Lib.) de Bary were isolated from Centaurea cyanus (blue bottle, S1) and C. moschata (sweet sultan, S2) “ornamental plants- Compositae Family”, Cuminum cyminum (cumin, S3), and Phaseolus vulgaris (bean, S4). These isolates were pathogenic to different vegetable fruits tested and showed significant differences in their pathogenicity. In addition with mycelium of S. sclerotiorum isolates were more aggressive for inducing rot than their culture filtrates. S. sclerotiorum isolated from bean was more aggressive and caused higher percentage in weight losses of vegetable fruits. Bean and cumin isolates gave the highest yield of sclerotial formation in both number and weight of sclerotia/fruit, whereas, the blue bottle (S1) and sweet sultans (S2) isolates exhibited the highest sclerotial weight. Also, results indicated that, the eggplant fruit was more favourable for growth of S. sclerotiorum isolates and recorded the highest weight of sclerotia. Meanwhile, potato tubers and carrot roots were less susceptible to infection for all isolates and showed no/or slight growth and yield of sclerotia when they were compared with other vegetable fruits.
The total phenols (free and conjugate) increased in diseased more than in healthy fruits. While, sugars content (reducing and non-reducing) was completely in contrast.
Sweet sultans and bean isolates showed the highest growth and yield of sclerotia/plate (number and weight) than those of the other two isolates. On the other hand, NA, YDA, GFM and PDA media were the most favourable for the growth while, Czapek’s medium was the lowest one.
Sclerotia of bean isolate produced apothecia, asci and ascospores under laboratory conditions. Sclerotia of cumin isolate produced apothcia, curl of the edge and no asci or ascospores were formed. On the other hand, sclerotia of the two other isolates showed no germination under the same conditions.
Sweet sultans and cumin isolates have the highest content of total protein while, bean isolate gave the lowest values. Sclerotia and mycelia content of protein were higher than culture filtrates.
Key Words: S. sclerotiorum isolates, Vegetable fruits, Losses of weight, Apothecia development, Total protein.
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