速生杉木优良无性系三阶段选择评价

【目的】根据杉木(Cunninghamia lanceolata(Lamb.)Hook.)131个无性系26 a的调查数据,探讨优良无性系幼龄期、半伐期和伐期选择的优劣。【方法】当无性系间具有极显著性差异时,按无性系的单株立木材积大于对照(湖南金洞林场杉木初级嫁接种子园种子培育出来的1年生健壮苗)30%的标准在6、13和26 a时分别进行优良无性系选择,并把6、13 a时选出的无性系与26 a选出的无性系进行比较,凡与26 a所选相同的无性系认定为选择准确的优良无性系。【结果】3种林龄阶段优良无性系选择的选准率:6 a是53.33%,13 a是86.67%,26 a是100.00%。在26 a时,优良无性系的^-H=19.46 m、D^-_1.3=30.43 cm、V^-=0.703 2 m³,而CK的H^-=16.19 m、D^-_1.3=22.87 cm、V^-=0.339 6 m³; 优良无性系现实增益ΔH^-=20.20%、ΔD^-_1.3=33.06%、ΔV^-=107.07%。【结论】因试验时间已达到了能使目标产品的经济性状充分表现出来的长度,伐期时的选择结果是准确的; 最早、最适选择年龄应是半伐期,虽仍有错选和漏选,但可提前1/2轮伐期就获得和利用优良品系,大大缩短育种世代,提高单位时间所获得的遗传增产效益; 幼龄时进行优良无性系选择,其错选和漏选比例很高,会给增产效益带来不确定性。

An evaluation of fast-growing Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) superior clone selection at three age stages

Objective]Based on the survey data of 131 Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) clones, the advantages and disadvantages of juvenile, semi-cutting and cutting selection of superior clones were discussed.Method]When there were extremely significant differences among clones, selection of superior clones aged 6 a, 13 a and 26 a was performed according to the standard of 30% higher single tree volume than the control clones (healthy seedlings cultivated by seeds from primary grafting in a Chinese fir seed orchard in Jindong Forest Farm, Hunan) and comparison of the clones selected was made for 6 a, 13 a and 26 a. When the same clones at 26 a were identified, these were deemed superior clones. Result] The selection rate of superior clones at the three ages was determined: 6 a, 53. 33%; 13 a, 86. 67%; and 26 a, 100. 00%. At 26 a, superior clones were evaluated to have the following measure-ments:H= 19. 46 m, (D-)1. 3 = 30. 43 cm,(V-) = 0. 7032 m3 ,while CK's (H-) = 16. 19 m, (D-)1. 3 = 22. 87 cm,(V-) = 0. 3396 m3 . Real gains of superior clones' Δ(H-) = 20.20%, Δ D1.3 = 33.06%, Δ(V-) = 107.07%. Conclusion]The selection result of the cutting period is accurate because the experiment reached the period of desirable performance and provided the desired e-conomic characteristics of the target product. The earliest and optimal age choice should be in the first half of the cutting period; although there are still faults and omittances, good quality lines can be obtained and utilized half of the rotation period in advance, which shortens the breeding generation and remarkably improves the yield per unit time to obtain ge-netic benefits. When the clones are young, the ratios of fault choice and omittance of superior clones are very high, which lead to uncertainty regarding the yield.