INTERACTIONS BETWEEN RACES OF FUSARIUM OXYSPORUM F.SP. DIANTHI AND CULTIVARS OF CARNATION
Isolates of race 2 induced regular Fusarium wilt symptoms in most cultivars. At the end of the test period, only the cultivars Revada and Novada remained externally symptomless.
Histopathological investigations of some cultivars showed a heavy degradation of cell walls and xylem parenchyma cells, with dark brown discoloration of the surrounding tissue.
Isolates of race 4 induced similar, but less aggressive symptoms. However, some interactions were found: Lena was less susceptible to race 4 than to race 2, but Pallas, Alice and Sam's Pride showed severe or complete wilting.
The pathogenesis of race 4 isolates was similar to that of race 2, with less vascular browning.
Race 1 induced atypical Fusarium symptoms in some cultivars. Most of them remained resistant, but Niky, Elsy and Sam's Pride showed a rapid necrosis of leaves, followed by wilting. The vessels of these cultivars had assumed a pale brown colour and were colonized heavily. However, no degradation of cell walls was observed.