落羽杉地理种源变异与选择

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.

Study on Provenance Variation and Selection of Taxod ium distichum

N ineteen Taxod ium distichum provenances ( inc lud ing 4 T. d istichum var. imbricatum provenances) w ereintroduced from 6 sta tes in U. S. A. and planted atDongha,i Jiangsu taking earlier introduced provenances o fT. distichum, CK1 and T. distichum var. imbricatum, CK2 as con tro ls to carry out the provenance tra ils. The g row th inseedling and juvenile stagew eremeasured. The results of g row thmeasurem ent o f 13-year-old trail stand show ed thatthere w ere significant variation among provenances in tree he igh,t dbh and vo lum e incremen,t the genetic variationcoeffic ients w ere 12. 91%, 23. 51% and 48. 51% and the broad-sense heritability w ere 0. 51, 0. 65 and 0. 60, respective ly. The grow th variation presented the stochastic variation among different provenance. Bo th better and poorer provenances in g row th tra its ex isted and no obv ious geographical trend o f provenance grow th varia tion w as observed. There w as no correlation be tw een the first year? s grow th and the 13th year? s grow th, but from the 3 rd yearon, there w as a significant corre lation w ith the 13 th year? s grow th. The proper early selection period are as fo llow s:3rd-5th year for prim ary cho ice, 8 th year for final cho ice. A ccord ing to the criterion of selecting the provenancew ith ind ividua l vo lume 50% higher than the CK1, Lou isianaQ. R., M ississipiR. F., A rkansas O. M. and Florida N. L. w ere se lected as super provenances, the ir average phenotype ga ins of tree heigh,t dbh and volume w ere 13. 86%, 21. 78% and 61. 11%, genet ic gains w ere 7. 07%, 14. 16% and 36. 67%, respectively. Compared w ithCK2, the average phenotype gains and genetic ga in w ere 14. 29%, 59. 89%, 148. 64% and 7. 29%, 38. 93% and89. 18%, respectively. The vo lume output of the super provenances w as extreme ly significan.t