A review of research progress on evolutionary history and genomics in Juglans

The genus Juglans (walnut) consists of about 22 species, which are relic of the Tertiary period, with a widely global distribution. This genus is rich in germplasm resources and has significant value for food, timber, ecology, economy, and medicine. Persian walnut (Juglans regia L.) is the most important with a long history of cultivation. In this article, the evolutionary history and progress in genomic research of walnuts were reviewed. The speciation, phylogeny, biogeography, and genomics were discussed in genus Juglans. The prospects for research on the genetic diversity and domestication history of these plants are also discussed. With the rapid development of molecular biological technology and the next generation sequencing techniques, the genomics, transcriptomics, metabolomics, whole genome resequencing, DNA methylation sequencing, organelle genomes, genome-wide association studies, and other omics would be useful tools in studying the evolutionary history, genomics, and breeding of Juglans.