Preliminary study on the interaction effect between genotypes and environment of growth traits in Pinus massoniana clones

  Objective  Pinus massoniana is one of the important fast-growing timber species in south China. In this study, phenotypic and genetic stability of DBH and tree height traits of 10 Pinus massoniana clones were studied at multiple sites, and excellent genotypes with high genetic gain were screened, so as to provide experimental basis for efficient cultivation of Pinus massoniana with suitable genotypes and quality and efficiency improvement of plantation.

  Method  The DBH and tree height of 10 3-year-old Pinus massoniana clones (M1 − M10) were measured from regional experimental forest in Ningming County (E1), Liuzhou City (E2), Bobai County (E3) and Qinzhou City (E4) of Guangxi, southern China. The growth traits and phenotypic variation of different genotypes were analyzed. Clone stability analysis and comprehensive evaluation were carried out to screen excellent genotypes with high productivity and good stability.

  Result  The growth variation of Pinus massoniana clones was rich, the total varation of DBH between clones at the same site and between clones at the same site was greater than tree height. Multi-point joint variance analysis showed that genotype, environmental conditions and genotype-environment interaction had significant effects on DBH and tree height growth of Pinus massoniana clones (P < 0.01). The growth performance of clones within the test site was different, and the growth performance of clones among different test sites was also different. The repeatability of DBH and tree height of clones at different sites was between 0.59 and 0.89, indicating they were mainly controlled by heredity. The results of genetic stability analysis showed that the DBH and tree height of M1, M2, M4, M5 and M7 clones grew faster and had good stability. Clone M8 had a special adaptability to the test site at Ningming County. Five superior clones (M1, M2, M4, M5, M7) were selected by comprehensive evaluation of DBH and tree height across four experimental sites. The genetic gains of DBH and tree height were increased by 37.90%−45.65% and 21.92%−24.38%, respectively, compared with the performance of seed orchard seedlings.

  Conclusion  The DBH and tree height of Pinus massoniana vary greatly among clones. Genotype, environment and the interaction between genotype and environment have significant effects on the growth traits of Pinus massoniana clones. The five clones, M1, M2, M4, M5 and M7, grow rapidly and stably, and bring high genetic gain, which could be appropriately promoted in Pinus massoniana cultivation areas.