楸树远缘杂交种花器官性状变异分析

Analysis on Variation of Floral Organ Traits in Distant Hybrids of Catalpa bungei

为明确楸树(Catalpa bungei)远缘杂交种花器官性状的表型变异程度和变异规律,以12株楸树远缘杂交种为材料,采用方差分析、相关分析、聚类分析等统计分析方法,对楸树远缘杂交种的花期物候特征、花序性状、花朵性状和花色性状指标进行研究。结果表明:楸树远缘杂交种的花期物候特征差异明显,楸梓杂交种为假三叉分枝,花芽分化能力强,嫁接当年持续多轮开花,花期长达100 d以上,表现出母本性状。楸梓杂交种的花器官特征差异显著,花序轴共7~9轮侧枝,主轴为无限花序,侧枝为二歧聚伞花序,从底层到顶层过度为聚伞花序,处于楸树有限花序到梓树无限花序的过渡性状。花总长度、花筒直径、花筒长度、花冠宽度、花梗长度、雌蕊长度、花药长度、雄蕊长度、不育雄蕊长度的变幅分别为35.42~50.36,10.84~16.13,16.57~24.68,31.58~44.87,9.07~31.99,19.44~27.52,4.85~5.89,13.93~21.10,3.66~6.79 mm,变异系数为10.88%~31.02%,多样性指数(H’)为1.36~1.93,并以9个性状指标将12株杂交种聚为大花型、中花型、小花型3类。楸树杂交种间花色差异显著,以L*、a*、b*值将12株杂交种的唇瓣花斑颜色聚为3类,分别是粉紫色型、紫红色型和紫色型。

In order to clarify the phenotypic variation degree and regularity of flower organ traits in distant hybrids of Catalpa bungei,12 distant hybrid species of C.bungei were used as materials,statistical analysis methods such as variance analysis,correlation analysis,and cluster analysis were used to study their phenological characteristics,inflorescence traits,flower traits,and color traits during flowering.The results showed that there were significant differences in phenological characteristics during the flowering period of the distant hybrid species of C.bungei.The hybrid of C.bungei and C.ovata was pseudo three-branch,with strong differentiation ability of flower buds,and multiple rounds of flowering in the year of grafting,and the flowering period of over 100 days,exhibited maternal traits.The floral organ characteristics of hybrid species of C.bungei were significantly different,with seven to nine rounds of lateral branches in the inflorescence axis,and the main axis was an infinite inflorescence,and the lateral branches were dichasium,and the transition from the bottom to the top was a cyme inflorescence,which was a transitional trait from a limited inflorescence of C.bungei to an infinite inflorescence of C.ovata.The variation ranges of total flower length,flower tube diameter,flower tube length,corolla width,peduncle length,pistil length,anther length,stamen length,and sterile stamen length were 35.42-50.36,10.84-16.13,16.57-24.68,31.58-44.87,9.07-31.99,19.44-27.52,4.85-5.89,13.93-21.10,3.66-6.79 mm,respectively.The variation coefficient ranged from 10.88%-31.02%,and the diversity index ranged from 1.36-1.93.Based on the nine traits,the 12 hybrids were clustered into three types:large flower type,medium flower type and small flower type.There were significant differences in flower color among C.bungei hybrids.The values of L*,a*and b*were used to cluster the labellum flower spots color of the 12 hybrids into three categories,namely pinkish purple,purplish red and purple.