engleski

Variability of Phomopsis spp. on croatian indigenous grapevine cultivars

Phytopathogenic fungi from genus Phomopsis are causal agents of Phomopsis cane and leaf spot, which is a disease of grapevine known in Croatia under name black spot. In recent years, knowledge about etiology of the disease has been updated with information that fungus Phomopsis viticola should not be regarded as the only cause of the disease, since also some other species are considered as possible causal agents. There are 16 species from genus Phomopsis/Diaporthe presently described from grapevine among which for four species (P. viticola, P. vitimegaspora, P. amygdali and D. viticola) various degree of pathogenicity on grapevine has been proven (Mostert et al., 2001 ; Niekerk et al., 2005). In order to obtain isolates of Phomopsis spp./Diaporthe spp. and determine their taxonomic identity and variability on Croatian indigenous grapevine cultivars, during winters of 2008. and 2009., grapevine cane samples from various grape growing regions of Croatia have been collected. After establishment of pure cultures, phenotypic characterization (morphological characters and vegetative compatibility grouping) and DNA sequence analysis (ITS-1, 5.8S, ITS-2) of the isolates was performed and their taxonomic status was determined, which was followed by testing of their pathogenicity on grapevine (Schilder et al., 2005). Additionally, in situ observations have been made regarding sensitivity of grapevine cultivars studied to P. viticola. Within large number of isolates from all wine growing regions of Croatia and on all indigenous cultivars, almost exclusive majority was identified as species P. viticola and proved to be highly pathogenic on grapevine. Also, considerable level of variability of these isolates with regard to belonging to 9 different vegetative compatibility groups, was found, which emphasizes variability of P. viticola on grapevine in general. Based on in situ observations, indigenous cultivars of grapevine differ with regards to sensitivity to P. viticola, with cultivars Plavac mali, Škrlet, Žilavka, Debit and other being sensitive, while Plavina, Babić, Žlahtina and other being relatively resistant.

Grapevine; Indigenosu cultivars; Phomopsis viticola; Varibility

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