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Abstract [Objective] This study aims to evaluate the nut traits of the dominant varieties of Ping􀆳ou hybrid hazelnuts cultivated in the northern Anhui and analyze the suitability of the varieties for processing, to provide a basis for the selection and popularization of the hazelnuts. [Methods] Nine varieties were selected as the dominant varieties based on their adaptation and yield in the northern Anhui. These varieties were analyzed and evaluated from different processing and utilization perspectives, such as baking, kernel, oil, and fresh-eating. [Results] (1) The distribution ranges of single nut mass, nut size, nut shape index, kernel mass, shell thickness, and kernel mass percentage of 9 dominant varieties were 2.54-4.40 g, 18.99 -21.49 mm, 0.67-1.02, 1.00-1.66 g, 1.53-2.41 mm, and 34.36%-47.01%, respectively. The distribution ranges of fat, protein, and soluble sugar contents were 50.50-58.00 g/(100 g), 21.10- 25.10 g/(100 g), and 4.08%-4.94%, respectively. (2) 8 fatty acids were detected from the hazelnut kernels, among which oleic acid was the highest with a distribution range of 81.21%-88.53%. The content of unsaturated fatty acids was 92.19%-94.61% among the total content of fat in hazelnut kernels. For mineral nutrition, the content of potassium, phosphorus, calcium, and magnesium in hazelnut kernels was relatively rich. (3) As for the processing capacity, the distribution ranges of single plant yield, fat production, and protein production of 9 dominant varieties were 1.52-2.20 kg, 330.50-503.47 g, and 141.68-224.40 g, respectively. [Conclusion] According to different consumption patterns, ‘Liaozhen 3’ is best for baking market, ‘Liaozhen 3’, ‘Dawei’ and ‘Liaozhen 4’ are best for kernel market, and ‘Dawei’, ‘Liaozhen 3’ and ‘Ping􀆳ou 545’ are best for the fresh-eating market. ‘Liaozhen 4’ can be used as oil processing varieties, ‘Liaozhen 1’ as functional protein beverage processing varieties, and ‘Dawei’ and ‘Liaozhen 9’ as high calcium processing varieties.

Ping'ou hybrid hazelnut is one of the most profitable tree nuts in China, but economically important cultivars must first be genetically validated to meet industrial demand. Traditional approaches used for cultivar identification are mainly trait-based and unreliable. Previous approaches at the DNA level, focusing on the identification of species or/and varieties that originated in China, were not used widely in hybrid hazelnut because there was no proper standard sample. In this research, a multiplexed fingerprinting test was conducted to allow for hazelnut cultivar identification using SSR markers derived from European hazelnut. Twenty-seven SSR markers were used to fingerprint 57 genetically unique Ping'ou hybrid hazelnut and related wild species. All markers showed a high level of polymorphism, as indicated by mean values for observed heterozygosity (Ho = 0.84), expected heterozygosity (He = 0.80), and polymorphism information content (PIC = 0.78). A total of 301 alleles were detected, and the number of effective alleles varied from 6 for KG817 and GB818 to 18 for B654, with an average of 11.2 alleles per locus. Moreover, the Shannon's information index (I) ranged from 1.293 for BR215 to 2.385 for B654, with an average of 1.908. The neighbor-joining tree, principal coordinate analysis, and Bayesian analysis revealed clear separation between hybrid cultivars and wild forms (Cluster/group I), as well as the differentiation within hybrid genotypes (Clusters/groups II and III). Additionally, the NJ dendrogram demonstrated a further split within Clusters/group III (III a and III b). Altogether, with the comparable SSR information of the European hazelnut cultivar 'Barcelona', the newly developed marker sets can assist in the germplasm identification of hazelnut cultivars and reproductive materials. Importantly, these combined SSR loci can be applied to characterize the genetic relationships and population structures among wild genotypes and hybrid cultivars, which will then provide information to guide hazelnut breeding based on their genetic background. [ABSTRACT FROM AUTHOR]

Corylus L. is an economically and phylogenetically important genus in the family Betulaceae. Taxonomic and phylogenetic relationships of Corylus species have long been controversial for lack of effective molecular markers. In this study, the complete chloroplast (cp) genomes of six Corylus species were assembled and characterized using next-generation sequencing. We compared the genome features, repeat sequences, sequence divergence, and constructed the phylogenetic relationships of the six Corylus species. The results indicated that Corylus cp genomes were typical of the standard double-stranded DNA molecule, ranging from 160,445 base pairs (bp) (C. ferox var. thibetca) to 161,621 bp (C. yunnanensis) in length. Each genome contained a pair of inverted repeats (IRs), a large single-copy (LSC) region and a small single-copy (SSC) region. Each of the six cp genomes possessed 113 unique genes arranged in the same order, including 80 protein-coding, 29 tRNA, and 4 rRNA genes. C. yunnanensis contained the highest number of repeat sequences, and the richest SSRs in six cp genomes were A/T mononucleotides. Comparative analyses of six Corylus cp genomes revealed four hotspot regions (trnH-psbA, rpoB-trnC, trnF-ndhJ, and rpl32-trnL) that could be used as potential molecular markers. Phylogenetic analyses of the complete chloroplast genomes and 80 protein-coding genes exhibited nearly identical topologies that strongly supported the monophyly of Corylus and simultaneously revealed the generic relationships among Betulaceae. The availability of these genomes can offer valuable genetic information for further taxonomy, phylogeny, and species delimitation in Corylus or even Betulaceae plants. [ABSTRACT FROM AUTHOR]