Annotation: Powdery mildew Erysiphe alphitoides is one of the most important pathogenic fungus infecting pedunculate oak Quercus robur in Europe. As the identification of this species with morphologic markers is unreliable, the molecular markers development is necessary. In this work, we developed primers for PCR amplification of cytochrome b gene fragment. The results show high level of intraspecific variability of this mitochondrial gene and revealed the indistinct taxonomy relations within E. alphitoides s. lat group.

La hibridació natural a plantes és un fenòmen àmplement conegut. És una important font de variabilitat que accelera l'evolució de les espècies. Es creu que és l'origen de moltes angiospermes, entre elles endemismes locals. Per altra banda, també pot tenir efectes negatius per la supervivència d'aquests endemismes, diluint els seus trets direfencials. En aquesta tesi s'estudia la possible hibridació natural que afecta a tres endemismes baleàrics (Viola jaubertiana, Lotus fulgurans i Helichrysum crassifolium), des del punt de vista dels marcadors moleculars basats en ADN i de la morfologia. S'avalua el paper de la hibridació natural la variabilitat, l'origen i la conservació d'aquestes espècies endèmiques. / Natural hybridization is a widely known process in plants. It is an important source of variation promoting species evolution. It is likely to be the origin of many angiosperms, including local endemisms. Oppositely, it is also regarded as a potential threat for endemisms survivorship, diluting their differentail traits. This thesis deals with putative natural hybridization processes involving three Balearic endemics (Viola jaubertiana, Lotus fulgurans i Helichrysum crassifolium), from the points of view of the DNA molecular markers and the morphology. The role of natural hybridization in the variation, origin, and conservation of the above endemics is evaluated.

In this study, strawberry fruit was taken as the studied model. An attempt was carried on trying to identify a unique DNA fingerprint in each of the selected different strawberry cultivars of Fragaria x ananassa Duch species available in Turkey. The basis of the study was to examine the fruit characteristics at the molecular level rather than at the morphological level. It is of great importance to differentiate and trace the origin of any variety by examining its DNA by using a very sophisticated molecular technique. In this case, DNA fingerprinting technique depending on the Simple Sequence Repeats (SSRs) markers which are also called Microsatellite markers were used. DNA fingerprinting technique reveals the specific DNA profile which is unique as a fingerprint for a fruit specimen and this DNA profile is the same and constant throughout different parts of the fruit as well as its developmental stages. In this thesis work, nine primers flanking the SSR markers already available in the online databases were designed hoping to detect SSRs that could differentiate among the five selected cultivars of strawberry.