Abstract: We selected the fast growing provenance-families of Mytilari laosensis to analyze the variation regularity of growth traits among provenances and among families of M.laosensis. We chose 116 families within 8 provenances of M.laosensis, and used genetic variance analysis and breeding value to analyze the growth traits among provenances and among families of M.laosensis. There were highly significant differences among growth characters at family and provenance level. At the age of 6, the average of height(H), diameter at breast height(D) and volume(V) of provenance GXPX was 9.50 m, 13.40 cm and 0.079 9 m³, and that was 1.28, 1.42 and 2.30 times of worst provenance GXFC, respectively. The average of H, D and V of family FC01 was 9.86 m, 15.31 cm, 0.1 016 m³, respectively. Mean individual volume of family PX01 was 4.01 times of worst family FC01 and 1.94 times of the average of total families by comparison. Using individual trait selection, two superior provenances were selected from eight provenances population tested, and genetic gain of H, D and V of those superior provenances reached as high as 8.87%, 11.79% and 34.70%, respectively. By using grade of breeding value selection, 12 superior families were selected from 123 families population tested, and genetic gain of H, D and V of those superior families reached as high as 11.57%, 17.35% and 52.06%, respectively. At the age of 6, the comprehensive growth of the best excellent provenances were GXPX and GXLZ, and the comprehensive growth of the best excellent families were PX01, LZ03, PX02, DB08, PX10, PX04, PX09, DB07, DB16, LZ05, JX16 and PX05. These superior provenances and families can be used as seed material to declare and promote.

Key words: Mytilaria laosensis, genetic variation, growth traits, breeding value, genetic gain