Morphological, pomological and genetic variability of dog rose (rose hip) genotypes (Rosa canina L.) Wild or dog rose (Rosa canina L.) is widespread in the form of spontaneous populations and ecotypes throughout Croatia. It is also known as šipak, pasja drača, šipurak etc. It is taxonomically classified into the genus Rosa, the subgenus Rosa and the section Caninae which is the largest and most complex in Europe. Relations within this genus remain unclear due to the difficulty in marking species boundaries and taxonomy which is extremely complex and is still being researched in depth. These differences are mainly the result of difficulties in identifying roses due to heterogamous canina meiosis, intra-species variability, predominant matroclinal inheritance, polyploidy, and interspecific hybridization. Dog rose is evolutionarily young, and in agriculture a relatively new fruit species of great potential whose cultivation, as well as selection work, is still in its infancy. The adaptability to different ecological conditions and the ability to hybridize within and with related species with the creation of new genetic combinations and polyploidy have allowed it to spread in temperate climates of the northern hemisphere. Its phylogenetic development is not yet complete, so there are difficulties in marking species boundaries. Due to its nutritional value, it has the potential to be used in medicine, cosmetics and the food industry. Because of this, there is interest in developing varieties and hybrids and increasing production in conventional and organic farming. In dog rose breeding, the greatest attention is paid to the quality of the fruit which is the main key to greater market expansion. In addition, the lack of prickles, processing potential, adaptability and resistance to pests are important. It is possible to isolate genotypes of agronomically desirable properties (time and length of ripening, amount of antioxidants, fruit size and firmness, fruit flesh ratio, vitamin C content, etc.) based on the knowledge about the variability of biological and pomological properties and create varieties suitable for plantation cultivation by methods of classical selection. So far, no systematic research of botanical and agro-biological properties has been conducted in Croatia, nor has agro-biodiversity of this species been used for breeding. The objectives of this study are the following: determine the level of variability within and between dog rose populations from different regions based on morphological, pomological and genetic analyses; analyze morphological, pomological and genetic variability between and within offspring on three generative offsprings. In this study, 57 autochthonous wild rose accessions (Rosa spp.) were used to evaluate morphological, pomological and genetic variability. For part of the in situ study, 24 accessions from three regions were analyzed: mountainous, continental and Mediterranean. As part of the ex situ study, 33 accessions of three elite plants originating from Korčula (P1), Malešnica (P2) and Prigorje Brdovečko (P3) were analyzed. Materials and methods To assess the phenotypic and genotypic divergence, dog rose (R. canina L.) accessions representing natural populations of dog rose collected from 15 localities in different geographical areas were analyzed. Morphological analyses to measure prickliness were performed by sampling shoots in late August or early September 2008 and 2010. For pomological analyses fruits were collected by random selection within the populations from the selected accessions at the end of August or the beginning of September 2010 and 2012. The following pomological traits were measured: fruit length (mm), fruit width (mm), fruit weight (g), fruit flesh weight (g), fruit flesh ratio (%), fruit shape index and total dry matter (%). Sampling of shoots, flowers and fruits was carried out on all accessions except those that were destroyed in the meantime in the original locations which is why there are variations in the number of samples. Sampling of plant material for genetic analyses was carried out in August 2008, at the same time as sampling of plant material for morphological and pomological analyses. Young leaves were taken from the tips of the shoots on all DNA extraction genotypes and stored until lyophilization. Lyophilization was carried out by cold drying in a lyophilizer to prevent the degradation of the DNA of the plant material. Storage of liofilized samples until DNA isolation was performed at -80 °C. Isolation and purification of genomic DNA of dog roses was carried out under a protocol according to the Doyle & Doyle modified method (1990). The concentration and purity of the isolated DNA was determined by agarose gel electrophoresis and by comparison with standards of known concentrations. Microsatellites and SSR (Simple Sequence Repeat) markers developed and assigned for the purposes of this research by the „Stichting Dienst Landbouwkundig Onderzoek Foundation (DLO)“ - Praktijkonderzoek Plant & Omgeving/Plant Research International (PPO/PRI), Plant Breeding, Wageningen, The Netherlands, were used to identify genotypes and determine genetic diversity and were previously used for similar research. Twenty-three SSR primers were tested preliminary, and six were selected for the final analysis (RhO517, RhAB15, RhD201, RhEO506, RhP507, Rh1402). The method developed by M. Schuelke (2000) with the universal M13(-21) primer according to published temperature conditions was used to amplify the markers. The PCR reaction was performed according to the protocol of Esselink et al. (2003). A capillary sequencer and Gene Mapper 4.0 software were used to visualize and separate the amplified fragments. Results and Conclusion Morphological and pomological analyses revealed significant variability of in situ and ex situ populations for important agronomic properties. Great phenotypic plasticity of morphological and pomological properties is the result of the influence of ecological factors and hereditary characteristics. In the in situ genotype study, the greatest variability of properties was determined in the continental region. Most of the agronomically important properties stand out for the RC35 and RC52 genotypes. The analysis of the pomological characteristics of ex situ populations of generative offsprings only allowed complete separation of the P1 population of the Mediterranean origin. The highest variability as well as the most desirable agronomic properties was determined within the P3 population. Genetic analysis has proven the taxonomic status of Croatian dog rose genotypes and determined the level of polymorphism and the degree of genetic distance between Croatian genotypes. The results obtained are consistent with studies of this and related species and can be used as a basis for further breeding research for the development and cultivation of new dog rose varieties and hybrids.