Growth and resin-yielding capacity determination of plus-tree clones of Pinus Massoniana

The growth traits and resin-yielding capacity of grafted clones of plus trees were determined and analyzed at the age of 20 in the high-resin-yield Masson pine orchard. The results indicated that all the growth traits，including height（ HT），diameter at breast height（ DBH） and stem volume（ VOL），and the resin-yielding capacity （RYC） varied significantly（ P<0.01） among clones. Furthermore，these traits consistently had a high（ 0.860–0.919） repeatability estimate（ broad-sense heritability）. When selection was made for growth and resin-yielding capacity，8 clones were identified，with VOL and RYC were both higher than the average value of the tested group. The mean HT，DBH，VOL and RYC of these selected clones were 11.14 m，28.28 cm，0.31780 m3 and 34.61 g/d respectively，and the expected genetic gains were 3.26% for HT，11.69% for DBH，25.70% for VOL，and 30.93% for RYC.