红锥家系遗传变异与优良家系选择

为选择红锥(Castanopsis hystrix)优良家系,对2–11年生红锥家系的生长性状和遗传参数进行了研究分析。结果表明,家系间在树高、胸径和单株材积上的差异达显著或极显著水平,家系的树高、胸径和单株材积受中等或中等以上遗传控制,具有很强的家系和家系内单株选择潜力;家系的单株材积变异幅度较大,胸径居中,树高的较小,显示出红锥家系间存在着丰富的变异;家系和单株遗传力随林龄的增大逐渐变小,到7–9年生时逐渐稳定。年度生长性状的相关分析表明,树高、胸径和单株材积的遗传相关系数随林龄逐渐增大,到7年生时最大,分别达到0.9602、0.9340和0.9849,之后趋于稳定,因此,7年生可作为早期选择的适合年龄。结合早期选择及形质指标,11年生时最终选择出优良家系10个,其平均树高、胸径和单株材积分别为13.95 m、14.34 cm和0.1229 m3,平均遗传增益分别为12.24%、18.69%和51.59%,其通直度、圆满度、分枝角度、最大分枝、冠幅、枝下高等形质指标也提高7.71%~12.94%。

Genetic Variation and Superior Family Selection of Castanopsis hystrix Families

In order to select superior families of Castanopsis hystrix in southern China, the growth traits and genetic parameters of C. hystrix families at ages from 2 to 11 years were studied. The results showed that the average height, diameter at breast height (DBH) and wood volume among families had significant differences. The average height, diameter and wood volume growth of families were genetic controlled at medium level or above, which indicated high selection potential among or within families. Wood volume had large variation among families, followed by DBH and height. Family heritability and individual heritability gradually decreased with age increasing, and stabilized at 7- to 9-year-old. The genetic correlation coefficient of growth traits gradually increased with age increasing, and reached maximum at 7 years old and then tended to stable. The genetic correlation coefficients of plant height, DBH and wood volume were 0.9602, 0.9340 and 0.9849, respectively, so that 7-year-old was suitable age for early selection of families. Combined with early selection and character indexes, ten superior families of 11-year-old were selected, their average height, DBH and wood volume were 13.95 m, 14.34 cm and 0.1229 m³, respectively, and their genetic gains were 12.24%, 18.69% and 51.59%, respectively. Compared with contrast of the superior provenance, the 10 selected superior families showed certain advantage on tree form qualities, such as stem straightness, fullness, branching angle, the biggest branch and crown breadth, which increased from 7.71% to 12.94%.