Graduate Research Assistant Michigan Technological University Houghton, Michigan
Body of Abstract: Genetic improvement of trees is essential for increasing the productivity and quality of forest products. We need to improve the trees’ ability to adapt to changing environments, including increases in frequency and intensity of biotic and abiotic stress. For efficient tree improvement, selecting a suitable breeding method is essential. Here, we reviewed the existing literature and conducted a meta-analysis using more than 1500 scholarly articles published between 1990-2021. We categorized all the articles into three broad tree improvement methods, including conventional or classical breeding, genomic or marker-assisted selection, and genetic engineering or modification. We found that higher adaptability, productivity, and quality are the main objectives of tree improvement throughout time. Growth, quality, and biotic and abiotic stress tolerance-related traits are considered the most important traits. In the 1990s to early 2000s, conventional breeding methods were used to improve these traits, but with the advent and development of state-of-the-art genetics, genomics, bioinformatics, and artificial intelligence tools, tree improvement has become more precise and rapid. Genomic selection and genetic modification of non-model tree species are getting more popular. Our analysis provides future directions and trends for selecting more efficient tree improvement techniques.