Investigation and analysis of seedling and experiment plantation of 40 half-sib-families from 4 seed provenances of Pinus tabuliformis

  Objective  This paper aims to study the performance of half-sib-families of Pinus tabuliformis from four provenances at seedling stage and after afforestation, and to explore the basis for formulating breeding strategies of the species.

  Method  The seeds were collected from four seed orchards, including Ningcheng of Inner Mongolia, Zunhua of Hebei, Shangzhuang of Shanxi of northern China, and Lushi of Henan, central China, which were representative of the above provenances, with a total of 40 half-sib families. Seedling and afforestation were carried out at Shanzhuang Forest Farm of Huachi, Gansu Province of northwestern China.

  Result  (1) No difference was observed in the preservation status of seedlings among tested provenances and families during seedling and experimental stand, which provided important information for further study. (2) The average seedling height of 4-year-old seedlings in the four provenance was 68.8−76.7 cm, and the ground diameter was 5.3−5.6 mm. Seedling height and ground diameter of 40 families varied in 53.4−105.4 cm and 4.2−6.6 mm. The maximum and minimum values of seedling height in a family ranged from 17.2 to 21.2 cm, which was equivalent to 17% to 34% of seedling height in that year. The variation coefficient of 4-year-old seedling height was 12.1%−18.2%, and the ground diameter was 10.4%−12.8%. The variation coefficient of seedling height and ground diameter were 3.1%−6.2% and 3.9%−6.9%, respectively. The tree height and DBH of 22-year-old trees from 40 families varied from 5.38 to 6.74 m and 8.13 to 14.25 cm, respectively. There were differences in origin, family and growth within family, and there was a large choice space. (3) The height order of 1−2-year-old seedlings in each provenance changed and then tended to be stable. The height order of 3-year-old and 4-year-old seedlings in families was basically the same. The height of 8, 12, 17, 21 and 22-year-old trees was correlated, and the DBH was correlated after 12-year-old. The sequence correlation coefficient between seedling height of 3−4-year-old and tree height of 22-year-old reached a significant level.

  Conclusion  No abnormality is found in the preservation condition of the tested seeds after long-distance seedling raising and afforestation; among the three levels of origin, family and within family, the height and diameter of seedlings and experimental forests vary greatly. Multi-level selection can improve the yield potential; the age of early selection may be significantly earlier.