| dc.description.abstract | Vascular wilt of carnation in Kenya was found to be caused by
Fusarium oxysp orum f. sp. dianthi, Five isolates of this pathogen
whose cultural characteristics differed on half-strength PDA were
isolated from wilted carnation stems and arbitrarily designated B, E,
F, G, and H. Isolates Band E differed significantly from isolates F and
G with respect the maximum disease severity (Kmax). Isolate H was
found to be intermediate (alpha = 0.01). Fusarium av enaceum was
also isolated from the wilted carnations and caused stem and bud rot
of carnation upon re-inoculation.
The carnation cultivar Lolita developed a functional symbiosis
with Glomus intraradices and G. mosseae, but not with G.
dimorphicum. Inoculation with VAM fungi enhanced the severity of
Fusarium wilt in Lavender Lace, but depressed disease severity in
Portrait and Scania. Phosphorous content did not differ between the
VAM inoculated plants and the uninoculated plants (alpha = 0.01).
The dry weights of VAM inoculated plants differed significantly from
those of uninoculated plants for Lavender Lace, but not for Portrait
and Scania (alpha = 0.01).
The spores of G. mosseae, G. fasciculatum, G. intraradices and G.
dimorphicum were found to retain their viability and infectivity with
13 months of cryopreservation in liquid nitrogen. Viability staining
with 3 -( 4,5 -dime thylthi azol-yl) -2,5 -diphenyl-2H -tetrazoli urn
bromide (MTT) was found to successfully differentiate viable from
non-viable spores of G. mosseae and G. fasciculatum. This stain,
however, failed to differentiate between viable and non-viable
spores of G. intraradices and G. dimorphicum.
The carnation growing areas of Kenya were found to have wide
variety of VAM fungi species. Fifteen different species of VAM fungi
spanning the genera Glomus, Acaulospora, Entrophospora, and
Gigaspora were isolated and identified from the soil samples
collected from these regions. | en |
