Molecular Basis of Forest Genetic Resource Improvement: Progress and Prospects

Presence of vast inter as well as intraspecific genetic diversity among thousands of forest tree species across the globe harbors useful potential traits of economic, ecological, scientific, and societal value for the human race. Unlocking this genetic diversity is vital for optimizing the utilization of economically valuable tree species so as to develop improved genotypes for maximizing the productivity within specific time and space constraints. Conventional tree breeding and improvement approaches such as selection and hybridization have been deployed in the past to enhance desirable traits of interest, but these processes typically require 20–30 years. However, there is an urgent need to accelerate the efficiency of forest tree breeding and improvement programs, so as to address the current rising demand for tree-based products and challenges posed by a changing climate and various biotic and abiotic stresses. Majority of the traits of economic and ecological importance in forest trees are of quantitative nature and controlled by many genes. To gain a comprehensive understanding of these traits, modern molecular and genomic technologies, such as quantitative trait locus (QTL) mapping and genome-wide association studies (GWAS), are indispensable. In such scenario, molecular genetics and breeding can act as a potential tool to harness the existing wide genetic variation in forest tree species via accelerating breeding cycles, optimizing parent selection, implementing marker-based selection, dissecting complex traits, studying association mapping, identifying quantitative trait loci (QTL), and understanding the molecular basis of trees adaptation to a changing climate. Moreover, the introduction of new traits of interest through the horizontal transfer of genes via molecular breeding has resulted in genetically modified trees in the shortest time frame. It is evident that the most significant advancements in forest genetic resource breeding in the foreseeable future will likely stem from genomics application to tree improvement. Just as genetics transformed tree breeding in the twentieth century, molecular genetics and genomics are spearheading a new tree breeding revolution in the twenty-first century.