Research progress on genetic improvement of
Suk. is one of the most widely distributed species of , the fourth most valuable timber species in north-eastern China and also a common tree species for landscaping. Over the past 30 years, effective progress has been made in genetic improvement and molecular breeding of . There has been extensive research on breeding techniques, including the collection and conservation of germplasm resources, provenance trials, intensive breeding techniques, crossbreeding and asexual propagation techniques, ploidy breeding and mutation breeding technology, genome sequencing, gene cloning, transgenic and molecular mechanisms of wood formation. A germplasm resource collection has been established by collecting different provenances, and full-sib and half-sib families. In addition, the geographic variation patterns of provenances have been revealed, and the provenance division and superior provenance selections made. flowering and seeding have been improved through intensive breeding techniques. Interspecific hybridization, intraspecific hybridization and parallel crosses were made using fine parents, and intensive seed orchards have been established. Systems of asexual propagation, including cuttings, grafting and tissue culture have been established. A tetraploid was successfully constructed and a triploid seed orchard established. The growth, wood property and resistance genes of have been cloned. An efficient transgenic system mediated by was established, and genes encoding insect resistance, drought resistance and salt tolerance, lignin synthesis, flowering, hormone transport and balance obtained. molecular markers were developed and the high density genetic map constructed. All this research has provided a model and data for the foundation of forest genetic improvement and applied research.