Supporting data for "A chromosome-level reference genome of the hazelnut, <i>Corylus heterophylla</i> Fisch."

<i>Corylus heterophylla</i> Fisch. is a species of the Betulaceae family native to China. As an economically and ecologically important nut tree, <i>C. heterophylla</i> can survive in extremely low temperatures (-30 to -40 C). To deepen our knowledge of the Betulaceae species and facilitate the use of <i>C. heterophylla</i> for breeding and its genetic improvement, we have sequenced the whole genome of <i>C. heterophylla</i>.<br>Based on over 64.99 Gb (~175.31 x) of Nanopore long reads, we assembled a 370.75 Mb <i>C. heterophylla</i> genome with contig N50 and scaffold N50 sizes of 2.01 Mb and 31.33Mb, respectively, accounting for 99.23% of the estimated genome size. Furthermore, 361.9 Mb contigs were anchored to 11 chromosomes using Hi-C links data, representing 97.61% of the assembled genome sequences. Transcriptomes representing four different tissues were sequenced to assist protein-coding gene prediction. A total of 27,591 protein-coding genes were identified, of which 92.02% (25,389) were functionally annotated. The phylogenetic analysis showed that <i>C. heterophylla</i> is close to <i>Ostrya japonica</i>, and they diverged from their common ancestor approximately 52.79 million years ago. <br>We generated a high-quality chromosome-level genome of <i>C. heterophylla</i>. This genome resource will promote research on the molecular mechanisms of how the hazelnut responds to environmental stresses and serves as an important resource for genome-assisted improvement in cold and drought resistance of the <i>Corylus</i> genus.