Genetic variation and early selection of growth traits in open-pollinated progeny of the third generation Cunninghamia lanceolata seed orchard from Xinfeng, Jiangxi province

This study is to select superior germplasm for the breeding and production of Chinese fir for Jiangxi Province. Growth traits(tree height, DBH and stem volume) from open-pollinated progeny of the third generation Chinese fir seed orchard from Xinfeng County forest seed farm were investigated and analyzed, superior families and individuals were selected. The results showed that, at age 8, the overall mean of tree height, DBH and stem volume was 7.06 m, 12.53 cm and 0.053 m³, with annual 0.88 m, 1.57 cm and 0.0066 m³ growth, respectively. The genetic variation coefficient of tree height, DBH and stem volume was 2.87%, 3.66% and 8.65%, respectively. Family heritabilities of these traits were 0.52, 0.51 and 0.47, separately. Their individual heritabilities were 0.18, 0.14 and 0.13, respectively. 10 families from the total 46 families were selected basing on family stem volume breeding value, with mean value of tree height, DBH and stem volume was 7.36 m, 13.33 cm, 0.0620 m³, and more 4.55%, 6.64% and 17.42% than tested population, respectively. The genetic gain of these traits was 2.36%, 3.39% and 8.19%, separately. Furthermore, 20 individuals were selected basing on individual stem volume breeding value, with mean value of tree height, DBH and stem volume was 8.53 m, 18.25 cm, 0.1240 m³, and more 21.16%, 46.00% and 134.85% than tested population, respectively. The genetic gain of these traits was 3.81%, 6.44% and 17.53%, separately.