灰楸无性系生长和形质性状变异与选择

目的]本研究考察了灰楸无性系生长(树高、胸径、单株材积)和形质(分枝度、分枝角、冠幅、树皮厚度、尖削度)性状,为灰楸优质用材良种选育和定向培育提供理论依据。方法]以5年生灰楸试验林33个无性系为材料进行多个性状的遗传变异分析、方差分析、重复力估算。利用主成分分析和隶属函数法综合选择优良无性系。结果]灰楸树高、胸径、单株材积在无性系间差异显著或极显著,其重复力为0.456～0.592。灰楸形质性状中,平均尖削度P1和P3在无性系间存在显著或极显著差异,且具有中等大小的重复力(0.479和0.415)。遗传相关分析中,单株材积与冠幅、树皮厚度、平均尖削度P1等存在显著或极显著较弱的正相关,相关系数为0.178～0.263。针对不同育种目标,利用主成分评价和隶属函数法最终选择出特定的优良无性系。结论]5年生灰楸无性系间各性状存在丰富的遗传变异,且生长性状受到中等的遗传控制,有较好的遗传改良潜力。灰楸无性系生长性状与形质性状具有独立性,可进行单独定向选择。灰楸无性系H3-1-9、H3-1-18、H3-1-10、H3-1-3、H3-2-16和H3-1-17可作为速生丰产良种;无性系H3-1-16、H3-1-19、H3-2-12和H3-2-9可作为优质用材的无性系;无性系H3-1-17、H3-1-10、H3-1-18和H3-2-16可考虑作为生长和形质综合改良的灰楸无性系在当地推广。

Variation and Selection of Growth and Trunk Shape Traits of Catalpa fargesii Clones

Objective] To study the breeding and directional cultivation of high-quality Catalpa fargesii clones by investigating the growth (tree height, DBH, individual volume) and trunk shape traits (branch degree, branch angle, crown, bark thickness, sharpness) of C. fargesii clones.Method] The analysis of genetic variation, variance and repeatability of several traits were carried out using 33 five-year-old C. fargesii clones. The optimal clones were selected by principal component analysis and membership function method.Result] The height, diameter, and individual volume of C. fargesii were significantly or extremely significantly different among the clones, and the repeatability was between 0.456 and 0.592. There were significant or extremely significant differences among clones with average sharpness P1 and P3 which had moderate repeatability (0.479 and 0.415). In the genetic correlation analysis, there was a significant or extremely significant positive weak correlation between individual volume and crown, bark thickness and average sharpness P1, the correlation was 0.178-0.263. According to different breeding objectives, the selection of clone was carried out by principal component evaluation and membership function method. The optimal clones selected by the two methods were combined.Conclusion] There was abundant genetic variation among the traits of the 5-year-old C. fargesii clones, and the growth traits are controlled by the genetic control in the middle and have good genetic improvement potential. The growth traits of C. fargesii clones are independent of the trunk shape traits and can be individually oriented. 6 C. fargesii clones are selected as fast-growing and high-yield varieties; 4 clones are selected as high-quality timber clones; and 4 can be considered as the clones improved both in growth and trunk shape traits and is suitable to be extended locally.