Sweet cherry trees (Prunus avium L.) are susceptible to a range of diseases, but there have been no studies to date about the viral infection of sweet cherry trees in Spain. To determine the phytosanitary status of Spanish sweet cherry plantations, the incidence and leaf symptoms induced by Prune dwarf (PDV), Prunus necrotic ringspot (PNRSV) and Apple chlorotic leaf spot (ACLSV) viruses were investigated during 2009. Young leaf samples were taken from 350 sweet cherry trees, corresponding to 17 cultivars, and were analysed by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). To associate the leaf symptoms with the virus, 50 mature leaves from each infected tree were visually inspected during the summer. The ELISA results revealed that 72 % of sweet cherry trees were infected by at least one of the viruses. PDV occurred in all sampled cultivars and presented the highest infection rate, followed by ACLSV and PNRSV. A high number of trees showed asymptomatic, in both single and mixed infections. The leaf symptoms associated with the viruses involved generalized chlorosis around the midvein (PDV), chlorotic and dark brown necrotic ringspots on both secondary veins and intervein regions (PNRSV), chlorotic and reddish necrotic ringspots (ACLSV) and generalized interveinal chlorosis (PDV-PNRSV).
Extracts from young leaves of nine sweet cherry (Prunus avium L.) and eight sour cherry (Prunus cerasus L.) varieties, located in the germplasm collection of the 'Direção Regional de Agricultura da Beira Interior' (Fundão, Portugal), were analysed for five isozyme systems in order to characterise these varieties and detect problems of synonymies and homonymies that frequently present. The sweet and sour cherry varieties analyzed showed low isoenzymatic polymorphism, being PGM and PGI the systems with the highest discrimination power. These systems presented seven and five different zymogrames, respectively. IDH showed four patterns. SKDH and 6-PGD grouped the varieties only into two patterns. The evident and discriminant restrictions of this type of analysis had got results that have only been a complement for agronomical and morphological characterization.
Nove extratos de folhas com desenvolvimento encompleto foram obtidos de 9 variedades de cerejeira (Prunus avium L.) e 8 de ginjeira (Prunus cerasus L.), localizados no campo de germoplasma da "Direcção Regional de Agricultura da Beira Interior" (Fundão, Portugal). Esses extratos foram analisados para 5 sistemas isoenzimáticos a fim de caracterizar essas variedades e simultaneamente detectar sinonímias e homonímias, freqüentes neste tipo de estudos. As variedades de cerejeira e ginjeira analisadas mostraram baixo polimorfismo isoenzimático, sendo que os sistemas PGM e PGI mostraram maior poder de discriminação. Estes sistemas apresentaram 7 e 5 zimogramas diferentes, respectivamente. IDH mostrou 4 padrões. SKDH e 6-PGD agruparam as variedades em 2 padrões. Os evidentes limites discriminatórios desse tipo de análise serviram somente de complemento para a caracterização agronômica e morfológica.