南方低山丘陵区泡桐无性系生长和干形综合选择

针对南方低山丘陵区缺乏适宜栽培的泡桐优良无性系的现状，本研究以湖北省赤壁市泡桐无性系测定林为对象，对5年生24个泡桐无性系的4个生长性状(胸径、主干高、总材积、接干高/苗干高)和2个干形性状(主干削度、形数)进行了遗传参数估算及性状间的相关性分析，并利用多性状指数法对其进行了评价和选择。结果表明:各性状在无性系间的差异达到显著或极显著水平。胸径和总材积的重复力较大，分别达到0.727 3和0.726 9，其余4个性状的重复力稍小，为0.201 8~0.383 7。4个生长性状间呈极显著的表型和遗传正相关关系，2个干形性状间呈极显著的表型和遗传负相关关系。形数与4个生长性状间均呈极显著的遗传和表型负相关关系。削度与胸径、主干高、接干高/苗干高的遗传正相关关系均达到极显著水平，与胸径、总材积的表型正相关关系分别达到极显著和显著水平。依据建立的多性状指数方程选择出适宜在南方丘陵区栽培的4个优良无性系，分别为609、204、302和207，入选率17%。与CK相比，入选群体的胸径、主干高、总材积、接干高/苗干高、削度和形数的遗传增益分别为3.93%、5.75%、21.84%、13.18%、5.72%和-0.45%，实际增益分别为5.40%、16.75%、30.04%、34.35%、28.34%和-1.62%。 

Comprehensive selection of growth and stem form of superior paulownia clones in the hilly region of southern China

To address the problem of lacking superior Paulownia spp. clones in the hilly region of southern China, the study was carried out with 5-years-old clonal test plantation contained 24 Paulownia spp. clones. The genetic parameter estimations of 4 growth traits including DBH ( D1. 3 ) , height of the trunk ( Ht ) , total volume( Vt ) and ratio of height of extened trunk to original trunk ( H1/H0 ) , and 2 stem form traits including taper of the trunk (β) and form factor(f) of clones were conducted, and correlations among these traits were analyzed. Furthermore, evaluation and selection of Paulownia spp. clones were conducted by comprehensive selection index method. Results indicated that: significant differences existed in each of the 6 traits among these 24 clones. The repeatability of D1. 3 and Vt were 0. 7273 and 0. 7269, respectively. The repeatability of other four traits was smaller ranging from 0. 2018 to 0. 3837. There were very significantly positive phenotypic and genetic correlations among 4 growth traits, and there were negative phenotypic and genetic correlations between the two form traits (βand f) . There were very significantly negative correlations between form factor and 4 growth traits. Genetic correlations betweenβand D1. 3 , Ht , H1/H0 were significantly positive. Phenotypic correlations between β and D1. 3 , Vt were significantly positive and positive, respectively. With a selection rate of 17%, clones 609, 204, 302 and 207 were selected as the superior clones by the method of comprehensive selection index. Compared with control, genetic and actual gains through these 4 clones were 3. 93% and 5. 40% for D1. 3 , 5. 75% and 16. 75% for Ht , 21. 84% and 30. 04% for Vt , 13. 18% and 34. 35% for H1/H0 , 5. 72% and 28. 34%for β, -0. 45% and -1. 62% for f, respectively.