Abstract: Launching stable selection research in the period of young forest and selecting excellent tree for adjacent areas is a key step of genetic improvement. We measured the height(H) and basic diameter(BD) of 21 families planted two years ago in the counties of Huinan and Qing’an, and the cities of Shangzhi and Dandong. H and BD differences among sites and families, and interaction between sites and families, were highly significant(P<0.01). Families 201 and 203 had excellent traits at Qing’an, followed by 203, 206, 201, 312, 316 and 205 at Shangzhi, 203 at Huinan, and 325, 203, 310, 204, 201 and 316 at Dandong. We obtained stable evaluation results using D based on the Tai model. Families 203 and 201 owned excellent growth performance and strong stability of optimal family, followed by 309, 308, 205, 316, 302 and 206, 311 greatly affected by environmental was sensitivity family, 325 inconsistent growth performance among sites was instability family. These results can provide a theoretical basis for excellent family selection and constitute a reference for birch superior parent selection.

Key words: birch crossbreeds, multi-site test, genetic stability