粗皮桉不同无性系的生长对比试验

Growth Differences Among Clones of Eucalyptus pellita

为筛选出适应性强、生长速度快、产量高的优良无性系,通过测定粗皮桉3个无性系的保存率、树高、胸径和材积指标,分析其不同时期的生长差异。结果显示:造林47个月时,无性系E53、E172和E138的保存率分别为90.0%、93.3%和51.6%,无性系E172的平均单株树高、胸径和材积为18.5 m、14.4 cm和0.16 m^(3),分别较无性系E53高5.6%、11.2%和25.0%,较E138高32.1%、38.3%和68.8%;无性系E172在不同时期的树高、胸径和材积变异系数均低于其他无性系,遗传稳定性较高;造林后的不同时期,无性系E172的树高、胸径和材积增长量均为最高或次高,造林后16~47月间,无性系E53的胸径增长量高于E172;无性系E172的综合表现最优,可作为优良无性系,E53相对次之,可作为候选优良无性系。桉树无性系生长性状年-年相关系数间存在极显著的正相关关系(P<0.01),无性系生长的早晚相关关系可为早期选择提供科学依据。不同性状调查末期与次末期的相关系数最高,亦表明优树的选择时期愈晚,其结果越准确可靠。

In order to select excellent clones with strong adaptability,fast growth rate and high yield of Eucalyptus pellita,the preservation rates,tree heights,DBHs and volume indices of three clones were analyzed.The results showed that at age 47 months,the preservation rates of clones E53,E172 and E138 were 90.0%,93.3%and 51.6%respectively,and the average tree height of(HT),diameter at breast height(DBH)and volume of clone E172 were 18.5 m,14.4 cm and 0.16 m^(3) respectively,which were 5.6%,11.2%and 25.0%higher than those of clone E53,and 32.1%,38.3%and 68.8%higher than E138 respectively.The variation coefficient of height,DBH and volume of clone E172 in different periods is lower than that of other clones,suggesting that genetic stability of E172 is higher.To different plantation ages,the increment of tree height,DBH and volume of clone E172 was the highest or the second highest.Among 16 to 47 months after afforestation,the increment of DBH of clone E53 was higher than that of E172.Therefore,clone E172 has the best comprehensive performance and can be used as an excellent variety,followed by E53 as a candidate excellent variety.There was a significant positive correlation among the annual growth traits of the three Eucalyptus clones(P<0.01).Meanwhile,the correlation coefficients between the late and the second end of the investigation of different traits were the highest,which also indicated that the later the selection period of superior trees,the more accurate and reliable the results.