Morphological, anatomical and genetic differentiation of Cornus mas, Cornus officinalis and their interspecific hybrid
Cornus mas L., C. officinalis Sieb. et Zucc. and their putative interspecific hybrid specimens were examined in order to describe their morphological, anatomical and genetic differentiation. Petiole length, number of leaf veins, pedicel and bract length, stone size, thickness of pericarp layers, the size and number of locules and the number of cavities were measured. Pedicels and bracts were shown to be significantly longer for C. mas (7.22 and 6.95 mm) and for the putative hybrid (9.11 and 6.61 mm) than for C. officinalis (6.86 and 5.81 mm, respectively). Average values of stone width and thickness, exocarp and mesocarp thickness, the number of cavities in the endocarp obtained for the putative hybrid differed significantly in comparison to C. mas and were similar to C. officinalis. Genotypes of the examined species were evaluated for genetic relationships using random amplified polymorphic DNA (RAPD) markers. Initial screening of the bulks of C. mas and C. officinalis compared with their putative hybrid using 72 decamer random primers resulted in the identification of 24 primers differentiating both species and their putative hybrid and showing reliable polymorphisms. Among a total of 485 amplified fragments, 89.7% were polymorphic, 18.8% were specific to C. mas individuals, and 18.6% were specific to the individuals of C. officinalis. In obtained profiles of the examined hybrid individual specific products absent in the genotypes of both parents were observed. The phylogenetic tree revealed two separate clusters including C. mas and C. officinalis accessions, respectively. The biggest genetic distance was observed for hybrid specimens, although the hybrid belonged to the C. mas cluster.