杉木早期选择的研究

<正>我们对于杉木早期选择的研究是从1964年起,于1979年完成。在杉木子代测定中,观测了各年到16年(或7年)的树高,胸径和材积生长。在1与16(或7)年观测值之间的秩次相关是非常显著的。 家系之间的相关性说明家系早期选择的可靠性,而家系内的相关性则证实家系内个体早期选择的可靠性。 根据子代测定结果,杉木在6—7年生时进行选择可以增大年度效益。在理论上,要比在25年生时进行选择,大约增加遗传效益60％。

A STUDY OF THE EARLY SELECTION OF CHINESE FIR

Our study on the early selection of Chinese Fir started in 1964 and was completed in 1979. Stem height, diameter and volume growth were measured at various ages up to that of 16 (or 7) in a Chinese Fir progeny test. Rank correlations between mea surements taken at the age of 1 and 16 (or 7) were very significant.Between-family correlations indicate the reliability of early selection of families; within-family correlations show the reliability of early selection of individuals within families. The rank correlation coefficients of stem growth at the age of 16 (or 7) and other ages are presented as follows: Ages compared (yr.)Early-selection of seedling (between classes)Ages compared (yr.)Half-sid progeny test Between-family Within-family Height 1 vs. 16 r, = 0.971** 1 vs. 7 rs = 0.692** r,>0.7** Diameter 4 vs. 16 r8 = 0.870** 3 vs. 7 r, = 0.819** Volume 4 vs. 16 r. = 0.981** 3 vs. 7 rk = 0.854** The high correlation coefficients indicate the high possibility for the less matured trees to be selected for mature performance. Since early selection shortens the selection cycle it is hopeful for breeders to increase genetic gains per unit of time.According to our progeny test results, Chinese fir can increase its yearly genetic gain when selection is made at its sixth or seventh year of age and this gain would theoretically be 60% larger than the gain to be obtained when Chinese fir is selected at the age of 25.