Juglans regia L. (English walnut) trees with cankers and dieback symptoms were observed in two regions in the Czech Republic. Isolations were made from diseased branches. In total, 138 fungal isolates representing 10 fungal species were obtained from wood samples and identified based on morphological characteristics and molecular methods: Cadophora novi-eboraci, Cadophora spadicis, Cryptovalsa ampelina, Diaporthe eres, Diplodia seriata, Dothiorella omnivora, Eutypa lata, Eutypella sp., Peroneutypa scoparia, and Phaeoacremonium sicilianum. Pathogenicity tests conducted under field conditions with all species using the mycelium-plug method indicated that Eutypa lata and Cadophora spp. were highly virulent to woody stems of walnut. This is the first study to detect and identify fungal trunk pathogens associated with diseased walnut trees in Europe.

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Molecular techniques (RAPD and i-PBS) were used to study genetic diversity within persimmon collection at Horticulture Faculty of Mendel University in Lednice. The aim of the work was to distinguish 14 known and 6 of unknown origin persimmon cultivars. The basic screening of 20 OPT primers was applied to 4 cultivars differring in the place of origin. Within the group of screened primers there were chosen those, which gave polymorphic repeatable strong and middle strong bands. Selected primers were used for the RAPD reactions within the whole persimmon collection. Three OPA primers previously described in the literature were also used for the RAPD reactions within the whole persimmon collection. Additional 16 i-PBS primers previously described in the literature were also used for i-PBS analysis of the whole group of cultivars. Amplification was successful with 12 i-PBS primers. The FreeTree software package was used to gen­erate a similarity matrix and then to produce a dendrogram using UPGMA analyses. The similarity dendrograms of all persimmon cultivars were created based on both approaches and also on combination of both analyses by program Tree View. All the dendrograms clearly separated the assessed cultivars into 4 clusters. There are cluster of American persimmons – Meader’ (1), ’Garretson’ (2) and ’Early Golden’ (3). They are representatives ofD. virginiana. Further part of dendrogram includes singleD. lotus(5), which is also clearly separated from other cultivars of the genusDiospyros. The third cluster includes interspecific hybrids ’Rossiyanka’ (10) and ’Nikitskaiya Bordovaiya’ (13), which arised from crosses ofD. virginianaandD. kaki. The last cluster is formed by cultivars of Japanese persimmon – ’Mikatani Gosho’, ’Zenjimaru’, ’Tone Wase’, ’Hiratanenashi’, ’Fuyu’, Chinese cultivar – ’Sansi’ and two Italian cultivars ’Vaniglia’ and ’Tipo’. They are clustered without significant distinction. The similarities and the differences revealed among incorporation of cultivars into groups were compared with the literature findings.

Wild edible fruits have been used centuries by local people mainly for nutrition purposes and they have attracted the attention of researchers in the last decade throughout the world. Among wild edible fruits, the strawberry tree (Arbutus unedo) is widely distributed mainly in Mediterranean countries. However, the lack of information about strawberry tree genetic resources in Mediterranean countries is a major cause of its low exploitation by breeders. For a practical use and exploitation of the strawberry tree native germplasm, phenological, morphological, and biochemical characterization of the plant is essential. In this study, some important phenological, morphological, and biochemical characteristics of sixteen local strawberry tree genotypes were determined. Significant variations (p < 0.05) were observed in most of the investigated phenological, morphological, and biochemical traits of the genotypes. The genotypes were harvested between 2–21 November. The fruit weight and the number of fruits per cluster of the genotypes varied from 3.89 to 6.86 g and 3.61 to 7.94, respectively. Vitamin C and total dietary fiber contents of genotypes were found quite variable, ranging from 58 to 93 mg/100 g and 7.04 to 12.36 g/100 g, respectively. The fruits of the strawberry tree include mainly fructose and glucose rather than sucrose. Local strawberry tree genotypes are found to be promising for further valorization through horticultural characteristics for breeding. Some genotypes had significantly higher fruit weight, vitamin C concentrations, total dietary fiber, and total phenolic concentration and may be good selections for producing health products.

Asian pears have become increasingly popular in the European market, but their cultivation history in Europe is rather short. Pear is a demanding species in terms of pollen -donor cultivar. The self-fertility phenomenon in Asian pear cultivars is not currently known. The study was conducted in a 6-year pear orchard (of 23 Asian and 5 European cultivars) at the Mendel University in Lednice (Czech Republic). The following traits were assessed: number of pollen grains, pollen viability, pollen grain germination, self-fertility and the pollen germination index (PGI). European cultivar -'Clapp's Favourite' and Asian cultivars -'Zao Su Li', and 'Shinko' were characterized by the highest number of pollen grains (over 50,000 grains). Asian cultivar 'Dangshansu Li' had the lowest number of pollen grains (less than 10,000 grains). The pollen viability of Asian pears ranged between 90 and 100%. Among European pears, 'Williams Bon Chrétien' and 'Clapp's Favourite' exhibited the highest pollen viability (90%), while the lowest viability was observed for the pollen of cultivars 'Beurré Bosc' and 'Alexander Lucas' pear (60-70%). Additionally, it was found that the germination capacity of the latter two cultivars was very weak (40-70%). After open-pollination all investigated cultivars exhibited greater pollen germination index (PGI) comparing to selfpollination. After the cross-pollination the percentage of pollen tubes below the 20% value at half the length of the pistil suggested a strong incompatibility between the crossed cultivars. The results clearly showed that none of the Asian cultivars are self-fertile, and they require a pollen -donor to produce fruits.