## 3 Results and Discussion
### Within-Population Diversity  
The number of distinct multi-locus genotypes corresponded to the number of individuals analyzed, indicating that the sampling strategy used successfully avoided the sampling of clones. The pairwise genetic distance (\(D_{\text{psa}}\)) between 101 sampled individuals ranged from 0.292 (seven different alleles out of 24) to 0.917 (22 different alleles) with an overall average of 0.659. Average pairwise genetic distances within populations were high in all populations analyzed, ranging from 0.615 (P8 Novo Virje) to 0.669 (P4 Kalnik), suggesting that crosses between relatives and biparental inbreeding are rare in wild hop populations, presumably due to the anemophilic pollen dispersal mechanism [3]. Null alleles were detected in three population/microastellite locus combinations, out of a total of 96 tests (3.13%). The null allele frequencies ranged from 0.122 (M11) to 0.180 (M06). All the examined populations were in Hardy-Weinberg equilibrium (HWE) and therefore null alleles were considered unlikely to substantially impact on the results [80]. The main parameters describing the intrapopulation diversity of eight wild hop populations are presented in Table 2. The average number of alleles (\(N_{a}\)) ranged from 6.333 in P3 Varazdin to 7.250 P6 Ludbreg population. Allelic richness (\(N_{ar}\)) varied from 5.955 (P1 Ozali) to 6.619 (P6 Ludbreg). A large number of private alleles was detected (38 out of 152 in total; 30.4%) distributed across all populations. A single private allele was detected in population P2 Rugvica, while the highest abundance of private alleles was detected in population P7 Prelog (10). The high abundance of private alleles in wild accessions has been confirmed in several studies. [PERSON] et al. [39] reported that compared to cultivated European and North American hop varieties wild hop accessions contained a higher number of private alleles, and this was also confirmed in the study of 80 wild hop accessions from Northern Italy in which 15 private alleles were detected, notably more than in cultivated accessions (6) [41]. [PERSON] et al. [37] found 25 private alleles in 12 wild populations from Central Italy. Breeding activities, and thus the selection of desirable traits within the limited genetic base, could lead to a decrease in the number of alleles, especially in low-frequency private alleles in cultivated hop. Private alleles can serve as tools for effective population and cultivar discrimination [81] and help to identify genotypes that could be useful in breeding programs [82]. The data obtained revealed high level of genetic variability in wild hop populations (average \(H_{\text{O}}\) = 0.770; average \(H_{\text{E}}\) = 0.759). Populations shared similar values of observed heterozygosity (\(H_{\text{O}}\)) and expected heterozygosity (\(H_{\text{E}}\)). The lowest values of both observed and expected heterozygosity were found in population P1 Ozalj (\(H_{\text{O}}\) = 0.689; \(H_{\text{E}}\) = 0.725) and the highest in P6 Ludbreg (\(H_{\text{O}}\) = 0.840; \(H_{\text{E}}\) = 0.789). The slightly higher values of observed heterozygosity in comparison to expected were detected in some of the populations (P3, P6, P7, P8). High phenotypic and alpha-acid content diversity of these wild hop populations was also reported [22]. In a recent investigation of wild hop populations,