Abstract:

Forest genetics and tree breeding, a discipline of forestry, is specialized in the genetics of forest trees and the theories and techniques used for breeding trees. It was initiated from studies on the geographical variation of tree species and was gradually improved with the formation of basic theoretical systems from genetics. The modern theory and the technical system of this discipline were slowly realized during the process of continuously promoting genetic improvements to meet the needs of the high-efficiency breeding of planted forests. This gave rise to a new era in the new century of in-depth developments in tree breeding by molecular design. After nearly two centuries of innovation and development, forest genetics and tree breeding have become a discipline that incorporates the biological characteristics of forest trees, basic research in genetics, and innovative breeding applications. Among these, the fundamental contributors to sustainable genetic improvement are the core breeding cycle with selection, mating and genetic testing based on the recurrent selection theory, and the development of higher-round basic groups, breeding groups, selection groups, and production groups. On this basis，it is possible to use distant hybridization to breed excellent varieties of forest trees with outstanding heterosis, or use polyploidy breeding via sexual polyploidization to comprehensively realize the utilization of heterosis and ploidy effect to achieve the improvement of multiple target traits in a single breeding cycle, or use molecular breeding techniques including transgenics and gene editing to effectively improve the specific traits of existing varieties and excellent germplasms. At present, the production of excellent varieties of forest trees still depends on traditional seed orchards and clonal propagation. For tree species that can only be propagated by seeds, the practical application of somatic embryogenesis technology will be an effective way to improve their genetics performance. As the goals of the past 200 years, forest genetics and tree breeding will bear greater responsibility in the future for breeding excellent varieties of forest trees with higher yields, better quality, stronger stress resistance, and wider adaptability, and applying these to forestry to ensure the production of more wood and forest products with fewer plantations, thus reducing the reliance and impact on natural forests.

Key words: forest trees, breeding, recurrent selection, breeding cycle, improved variety