Growth evaluation and selection study of elite clones and its offspring families in Pinus koraiensis

  Objective  This paper aims to evaluate and select elite germplasm of Pinus koraiensis, and provide materials for seed orchard upgrading.

  Method  The 37-year-old parental clones and 35-year-old offspring half-sib families from the same elite trees in Wangqing Forestry Bureau, Jilin Province of northeastern China were used as materials, and we measured their growth traits.

  Result  Variance analysis showed that the clone or family growth traits had strongly significant differences among the sources of variation (P < 0.01). The phenotypic coefficient of variation of all traits for clone and family ranged from 4.19% to 25.88% and 4.51% to 34.33%, respectively. The clone repeatability of all traits ranged from 0.45 to 0.74, and the family heritability of all traits ranged from 0.70 to 0.85, the single heredity of all traits ranged from 0.29 to 0.66, indicating medium-high level of repeatability and heritability. Correlation analysis results showed that there were significantly positive correlations (r > 0.47, r > 0.57) of some traits (such as DBH, tree height, volume, crown width) for clone and family. The results of principal component analysis showed that the cumulative contribution of the two principal components was 68.50% and 73.37%, respectively, the DBH, tree height, volume and crown width contributed greatly to principal component Ⅰ, and described the growth characters of P. koraiensis, so these traits can be used as an evaluation index for further selection of superior germplasm of P. koraiensis. To select the elite clone and family by multiple-trait comprehensive evaluation, 3 excellent clones and families were selected with 10% selection rate, the clone and family genetic gain of growth traits (the DBH, tree height, volume and crown width) ranged from 3.03% to 14.40%. Selecting the elite individual within the excellent families, 9 excellent individuals were selected and their genetic gain of growth traits (the DBH, tree height, volume and crown width) ranged from 6.98% to 37.37%.

  Conclusion  The selection of excellent clones, families and individuals based on growth traits can be used to improve seed variety declaration and provide theoretical basis for the selection and breeding of improved variety of P. koraiensis.