杉木半同胞子代胸径变异和大径材家系选择

为选择适宜培育大径材的优良家系,以广东杉木(Cunninghamia lanceolata)第二代种子园半同胞子代(28个半同胞家系)和2个对照(第一代、第一代改良种子园混合种)为对象,对林龄4、9、11、16和21 a的杉木胸径进行持续测定。结果表明,相同林龄家系间的胸径差异极显著(P0.01),表型变异系数和遗传变异系数分别为4.43%～6.29%和2.95%～3.62%。家系胸径的遗传力较高(0.335 9～0.548 6),且随年龄的增长呈增大趋势,至林龄16 a时达到0.548 6,随后趋缓。林龄9 a的胸径与早期(4 a)、晚期(11、16和21 a)的胸径遗传相关性最为密切。基于多年度育种值和林龄21 a时家系各径级立木占比统计,共选择出F5、F9、F21等3个适于培育大径材的优良家系。

Diameter Variation of Chinese Fir Half-sib Progenies and Selection for Large-size Timber Families

In order to select superior families for breeding large-size diameter of Chinese fir (Cunninghamia lanceolata), the diameter at breast height (DBH) of 28 half-sib progenies in second-generation seed orchard of Guangdong were continuously determined at 4, 9, 11, 16 and 21 years old, compared with 2 control families from primary seed orchard and 1.5 generation seed orchard of Guangdong. The result showed that DBH of Chinese fir had significant difference (P<0.01) among families at the same age, and the phenotypic and genetic coefficient ranged from 4.43% to 6.29% and from 2.95% to 3.62%, respectively. The family heritability of DBH increased from 0.3359 at 4 years old to a peak of 0.5486 at 16 years old, and then became stable at 21 years old. The genetic correlation of DBH at 9 years old was close to that at 4, 11, 16 and 21 years old, respectively. So, according to multi-year breeding values and the ratio of diameter-grade volume of family at age of 21, three families (F5, F9 and F21) were selected as the superior families for large-size timer cultivation.