ISHS Acta Horticulturae 307: IV International Symposium on Carnation Culture
SUSCEPTIBILITY REACTION OF CARNATION CULTIVARS TO FUSARIUM OXYSPORUM F.SP. DIANTHI IN AN INFESTED FIELD AND IN SPORE SUSPENSION * |
| Authors: | Y. Ben Yephet, M. Reuven, M. Lampel, Y. Szmulewich, Y. Nitzani, Y. Mor |
| Abstract:
Carnation wilt caused by Fusarium oxysporum f.sp. dianthi (F.o.d.) was compared in two methods of inoculation during 3 years. The first method consisted of immersing rooted stem cuttings in spore suspensions (106 spores/ml), planting them in pots filled with tuff, and rating the disease level 9–10 weeks after inoculation. The second method involved planting the candidate cultivars in an artificially infested field and recording wilt reaction seven times, 85–180 days after planting. Similar wilt reactions in pots and field were found only in the susceptible cvs. Fantasia and Raggio de Sole, where 90–100% of the plants wilted. In other cultivars of various degrees of field tolerance, the spore suspension test was not predictive. In the field, the wilt reaction of cvs. Lior, Galit, Pallas and Eveline was 90%, 43%, 19% and 7.2%, respectively; in the spore suspension test they were completely tolerant. Tolerance reaction of carnation cultivars to the pathogen in the field was expressed by differing percentages of plants wilted or by delaying disease progress as compared with the susceptible cultivars. When the cultivars inoculated in spore suspensions were planted in a mixture of tuff and peat (1:2 v/v) instead of in tuff alone, the wilt reaction was 90%, 5%, 50% and 25% in Lior, Galit, Pallas and Eveline, respectively, but still not similar to the wilt reaction observed in the field. In conclusion, by root dip inoculation in a spore suspension, it is possible to distinguish between highly susceptible and tolerant cultivars. However, in order to determine the degree of tolerance, it is necessary to test the cultivars in a field naturally or artificially infested with F.o.d. propagules. | |
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