Objective This study aimed to conduct a multi-trait comprehensive evaluation of open-pollinated families of Larix olgensis to preliminarily screen superior families and provide high-quality materials for the construction of a breeding population.

Method The study utilized 12-year-old multi-site trial forests comprising 39 open-pollinated families from three locations: Qingshan Forest Farm in Linkou County, Heilongjiang Province; Hada Forest Farm in Fushun County, Liaoning Province; and Daguijia Forest Farm in Qingyuan County, Liaoning Province of northeastern China. Growth traits were investigated, and wood property traits such as stress wave velocity and amplitude were measured using non-destructive testing techniques. Needle samples were collected for DNA extraction and InDel molecular marker analysis. The Burke-Gilman comprehensive evaluation method was applied with a 25% selection rate to perform both conventional evaluation (considering growth and wood properties) and comprehensive evaluation (integrating growth, wood properties and genetic diversity).

Result (1) All traits of L. olgensis showed highly significant differences (P < 0.01) among families, locations and their interactions. The coefficient of variation ranged in 10.54%−64.34%, indicating substantial selection potential. The family heritability ranged in 0.693−0.798, indicating a high level of genetic control. (2) Molecular variance analysis revealed that genetic variation primarily occurred among individuals. The overall genetic differentiation index was 0.148, indicating moderate genetic differentiation. The average Shannon-Wiener diversity index of the population was 0.514, reflecting high overall genetic diversity. The inbreeding coefficients of all families were less than 0, suggesting excessive heterozygosity in each family. The population was broadly divided into three clusters, including Xiaobeihu 1, Muleng and mixed group. (3) Compared with comprehensive selection, conventional selection resulted in higher actual genetic gains but lower genetic diversity. Through the integration of both methods, six superior families of LK299, NB124, NB173, LK450, CH309, and CH171 were selected.

Conclusion The growth and wood property traits of L. olgensis families exhibit rich genetic variation among families, with overall high genetic diversity. The six selected superior families belong to different subpopulations, balancing phenotypic traits and genetic diversity, and can serve as excellent materials for improving variety production in L. olgensis.