杉木种子园遗传效益的估算

<正>杉木无性系种子园的面积3.0公顷,包括46个无性系,于1966年进行嫁接。实生苗种子园的面积0.6公顷,包括30个自由授粉的家系,于1967年栽植。 根据子代测定的结果,优良母树的后代,在相同立地条件和一致的经营管理下,在7年生时,材积生长比一般对照大“14—39％;种子园的后代则比对照大33—74％。然而,当半同胞子代在四个不同地点测定时,其树高生长比对照大6—22％。 7—13年生的杉木树高、胸径和材积的广义遗传力是按家系和单株估算的。单株树的树高和材积遗传力估值是0.2,而直径的遗传力估值为0.3。家系树高、胸径和材积遗传力估值是0.4。2—4年生时,全同胞家系树高狭义遗传力估值是0.3。 期望遗传效益是在各种不同选择强度下计算的(P_1=0.01;P_2=0.1,0.2和0.3;P_3=0.01,0.02和0.05)。对第一代无性系种子园在材积生产和其它生长性状方面的遗传效益进行预测。杉木各生长性状的遗传效益的估值如下:树高6.54一6.7.％,胸径19.12—19.68％,材积27.38—23.09％。然而,从第一代实生苗种子园在胸径生长方面预测的遗传效益值接近于20—26％。 第二代亲木的选择是在于代测定的材料中进行的。当假定把整个杉木育种方案的成木与期待增加的收益结合起来考虑时,其所得到的净收入值,证实了子代测定的实用价值。研究证明,每一公顷种子园的期待净收入元。

ESTIMATES OF GENETIC GAINS FROM THE SEED ORCHARD OF CHINESE FIR (CUNNINGHAMIA LANCEOLATA HOOK.)

The clonal seed orchard covers an area of 3.0 hectares with about 46 clones which were grafted with mature scions in 1966. The seedling seed orchard covers an area of 0.6 hectares with about 30 open-pollinated families which were planted in 1967. Both are located in Yangkou Forest Form, Fujian Province. A ccording to the result of progeny test, under similar site conditions and uniform managements, the offsprings of superior mother trees yielded 14 to 39 percent more and the offsprings in the clonal seed orchard yielded 33 to 72 percent more in volume growth as compared with the common check trees at the age of 7. However, the offsprings of the half-sib progeny tested in four different sites yielded only 6 to 22 percent more in height growth as compared with the common check trees.The estimates of the broad-sense heritability of the 7-year and 13-year old Chinese Fir for the height, diameter and volume were worked out on the basis of individuals and families. The individual tree heritability estimate for height and volume is 0-2, and that for diameter is 0-3. The family heritability estimates for height, diameter and volume are 0-4 respectively. At the 2 to 4-year stage, the full-sib family narrow-sense heritability estimate for height is 0-3.The expected genetic gains were calculated at different levels of selection inten: sities (P1 = 0.001; P2 = 0.1, 0.2 and 0.3; P3 = 0.01, 0.03 and 0.05). Estimates have been made on genetic gains in volume production and other growth traits from the first generation clones. Theestimates of the genetic gains in various growth traits of Chinese Fir vary as follows: height 6-54-6.70%, diameter 19.17-19-68%, volume 27.38-28.09%. However, a genetic gain of about 20% or 26% growth in diameter were anticipated for the first generation seedling seed orchard.Selections for second-generation parents were made from progeny test materials.