落羽杉地理种源变异与选择

Study on Provenance Variation and Selection of Taxodium distichum

从落羽杉原产地美国6个州引进19个落羽杉(包括4个池杉)种源,以国内早期引种的河南鸡公山落羽杉(CK1)和池杉(CK2)为对照,于1993年3月在江苏东海进行种源试验造林。在苗期和幼林期测定基础上,对13 a种源试验林生长测定结果表明:种源间树高、胸径和材积生长存在显著变异,其遗传变异系数分别为12.91%、23.51%和48.51%,广义遗传力分别为0.51、0.65和0.60。在同一区域,既有生长表现较好的种源,也有生长表现较差的种源,种源生长变异未见明显的地理趋势。落羽杉种源苗期(1 a)与13 a生长没有相关性,3 a开始与13 a生长相关性显著。落羽杉种源早期选择的合适年龄为3—5 a初选,8 a决选。按单株材积比CK1增加50%的选择强度,选出路易斯安娜Q.R.(1600号)、密西西比R.F.(503号)、阿肯色O.M.(304号)和佛罗里达N.L.(701号)4个优良种源。其树高、胸径和材积的平均表型增益为13.86%、21.78%和61.11%,遗传增益达7.07%、14.16%和36.67%;与CK2相比,平均表型增益和遗传增益分别达14.29%、59.89%、148.64%和7.29%,38.93%、89.18%,丰产性十分显著。

Nineteen Taxodium distichum provenances （ including 4 T. distichum var. imbricatum provenances） were introduced from 6 states in U. S.A. and planted at Donghai, Jiangsu taking earlier introduced provenances of T. distichum, CK1 and T. distichum var. imbricatum, CK2 as controls to carry out the provenance trails. The growth in seedling and juvenile stage were measured. The results of there were significant variation among provenances in tree growth measurement of 13-year-old trail stand showed that height, dbh and volume increment, the genetic variation coefficients were 12.91% , 23.51% and 48.51% and the broad-sense heritability were 0.51, 0.65 and 0.60,respectively. The growth variation presented the stochastic variation among different provenance. Both better and poorer provenances in growth traits existed and no obvious geographical trend of provenance growth variation was observed. There was no correlation between the first year＇ s growth and the t3th year＇ s growth, but from the 3rd year on, there was a significant correlation with the 13th year＇ s growth. The proper early selection period are as follows： 3rd-5th year for primary choice, 8th year for final choice. According to the criterion of selecting the provenance with individual volume 50% higher than the CK1, Louisiana Q. R. , Mississipi R. F. , Arkansas O. M. and Florida N. L. were selected as super provenances, their average phenotype gains of tree height, dbh and volume were 13.86%, 21.78% and 61.11%, genetic gains were 7.07%, 14.16% and 36.67%, respectively. Compared with CK2, the average phenotype gains and genetic gain were 14.29%, 59.89% , 148.64% and 7.29% , 38.93% and 89.18% ,respectively. The volume output of the super provenances was extremely significant.