滇楸种质生长性状遗传变异及表型性状遗传多样性分析

为明确滇楸种质生长和表型性状的遗传变异程度及遗传多样性大小，提出合理的杂交育种策略。本研究对滇楸20个无性系进行了连年的生长性状测定，测量了其叶长、叶宽、皮孔长、皮孔宽、皮孔密度等表型性状。研究结果表明滇楸种质1、3、4和5 a树高及1~6 a胸径在无性系间差异均达显著水平。树高遗传变异系数和重复力随年份变化波动较大，胸径遗传变异系数和重复力年份间较为稳定，且重复力较高。表明滇楸种质胸径受遗传控制程度较大，且稳定性更高。滇楸种质叶长和叶宽遗传多样性指数较高，分别为2.016和2.012。皮孔性状遗传变异系数较高，皮孔长、皮孔面积和皮孔密度表型变异系数均超过20%，遗传变异系数均超过15%。说明滇楸种质表型变异较为丰富，具有较好的遗传改良基础。相关分析结果表明皮孔密度与生长呈负相关，皮孔大小与生长呈正相关。聚类分析将滇楸种质划分为4类，第Ⅰ类皮孔面积最大，密度最小；第Ⅱ类生长最慢，叶长最大；第Ⅲ类生长最快，叶形最宽；第Ⅳ类叶柄最长。

Genetic Variation of Growth Traits and Genetic Diversity of Phenotypic Traits in Catalpa fargesii f. duclouxii Germplasm

The experiment was conducted to study genetic variation and genetic diversity of Catalpa fargesii f. duclouxii germplasm and put forward reasonable cross breeding strategy. The perennial growth traits and the leaf length, leaf width, lenticel length, lenticel width, lenticel density of 20 clones were measured. The results showed that 1, 2, 3, 4 and 5 a height and 1-6 a DBH were significantly different among clones. Repeatability and genetic variation coefficient of height changed in volatility with years change, however, those parameters of DBH were relatively stable. Repeatability of DBH was higher than height. It indicated that the degree of genetic control of DBH was stronger than height. The genetic diversity index of leaf length and leaf width was high, they were 2.016 and 2.012, respectively. Phenotypic variation coefficients of lenticel length, area and density were more than 20% and the genetic variation coefficient were more than 15%. There was ample morphological diversity among C.fargesii f. duclouxii clones. By the correlation analysis, the lenticel density was negatively correlated with growth, but lenticel size and growth traits had positive correlation. The germplasms were divided into four types by cluster analysis, the first type had maximum lenticel area and the minimum lenticel density; type Ⅱ grew the most slowly, but it had maximun leaf length; type Ⅲ had fastest growth rate and maximun leaf width; and the type Ⅳ petioles were longest.