Objective  To lay the foundation for the genetic improvement of high generation of Picea crassifolia, the genetic variations of growth traits in the half-sib families of Picea crassifolia were studied, and the superior families were screened out.

  Method  With 100 Picea crassifolia half-sib families as the research objects, we investigated tree height (H), height increment in that very year (I), ground diameter (GD), and crown width (CW) of 15 and 20-year-old offsprings, variance and estimation of genetic parameters and parents’ general combining ability of half-sib families were analyzed, and on the basis of comprehensive evaluation on growth traits of parents, superior families were selected.

  Result  4 growth traits were all significantly different (P < 0.01) among the half-siblings at the age of 15 and 20. The family heritability range of each trait in different ages was 0.554 − 0.855, and the family variation coefficients of growth traits ranged from 8.33% to 19.49%. The ranges of general combining ability (20-year-old) of H, GD, I and CW were −39.22 − 47.56, −1.19 − 1.05, −5.91 − 6.34 and −21.49 − 25.40, respectively. The correlation analysis results showed that there was a significant positive correlation among all growth traits (0.308 − 0.817). The growth traits were used to evaluate 15 and 20 years old half-sib families, 7 families were finally selected, and the average H, I, GD, east-west CW and south-north CW of the selected families in 20 years old were 209.40, 20.71, 6.33 and 141.87 cm, respectively, and the average genetic gain of each trait was 14.12%, 2.07%, 8.01% and 10.42%, respectively.

  Conclusion  There are abundant genetic variations among families of Picea crassifolia. Seven families with excellent growth traits were screened out, i.e. No. 49, No. 51, No. 60, No. 64, No. 108, No. 123 and No. 132. The selected superior families can provide high quality breeding materials for high generation seed orchards.