花楸树种源间表型性状的地理变异分析

为揭示花楸树 Sorbus pohuashanensis (Hance) Hedl.]表型性状的地理变异规律,对来源于山东、山西和河北的7个花楸树种源171个家系2年生幼苗的株高、地径、复叶长、复叶宽、叶柄长、小叶长、小叶宽、复叶长宽比和小叶长宽比9个表型性状进行了比较,并进行了方差分析、主成分分析(PCA)及聚类分析；在此基础上,分析了各种源株高和地径与主要地理-气候因子的相关性.结果表明:在种源间及种源内家系间 9个表型性状均有极显著差异；7个种源幼苗的平均株高和平均地径变幅分别为54.21～ 63.07 cm和8.12 ～8.45 mm；叶片各项指标的变幅相对较小,变幅最大的为叶柄长,为1.87 ～3.05 cm;9个性状在种源间的表型分化系数为12.98％～54.04％,其中小叶长的表型分化系数最大(54.04％),株高的表型分化系数最小(12.98％),种源间各性状的平均表型分化系数为34.38％.主成分分析结果表明:花楸树表型性状之间的差异主要表现在小叶长和宽,其次是复叶长和宽.通过聚类分析可将7个种源划分为2组,其中,山东崂山和泰山种源聚为I组；山西庞泉沟及河北白石山、驼梁山、雾灵山和塞罕坝5个种源聚为Ⅱ组.相关性分析结果表明:花楸树株高与纬度呈显著负相关、与降雨量呈显著正相关(P=0.05)；地径则与经度、年均温和年降雨量呈显著正相关(P=0.05).研究结果显示:花楸树的各项表型性状在种源间以及种源内家系间存在丰富的变异、遗传分化显著,其中种源内家系间的变异是花楸树表型变异的主要来源.初步判断花楸树表型性状的变异为经纬向双重变异模式,其中纬度起主要作用.

Analysis on geographic variation of phenotypic traits of Sorbus pohuashanensis among different provenances

In order to reveal geographic variation law of phenotypic traits of Sorbus pohuashanensis(Hance) Hedl.,nine phenotypic traits including height,ground diameter,compound leaf length and width,petiole length,leaflet length and width,ratio of length to width in compound leaf and in leaflet of two-year-old seedlings from 171 pedigrees of seven provenances from Shandong,Shanxi and Hebei provinces were compared,and variance analysis,principal component analysis(PCA) and cluster analysis were also carried out.On this basis,the correlation of height and ground diameter of seedling from different provenances with main geographical-climatic factors was analyzed.The results show that there are extremely significant differences in nine phenotypic traits among provenances or among pedigrees within provenance.The change range of average seedling height of seven provenances is 54.21-63.07 cm and that of average ground diameter is 8.12-8.45 mm.The change range of leaf indexes is relatively small and that of petiole length is the largest with the range of 1.87-3.05 cm.The phenotypic differentiation coefficients of nine traits among provenances are 12.98%-54.04%,in which,that of leaflet length is the maximum(54.04%) and that of height is the minimum(12.98%),and average of phenotypic differentiation coefficients among provenances is 34.38%.PCA result shows that the difference among phenotypic traits of S.pohuashanensis mainly presents in length and width of leaflet,and then in those of compound leaf.By means of cluster analysis,the seven provenances can be divided into two groups,in which,Ⅰgroup contains two provenances from Laoshan and Taishan of Shandong Province,and Ⅱ group contains five provenances from Pangquangou of Shanxi Province,and Baishishan,Tuoliangshan,Wulingshan and Saihanba of Hebei Province.The correlation analysis result shows that seedling height of S.pohuashanensis has a significantly negative correlation with the latitude and a significantly positive correlation with annual precipitation(P=0.05),while ground diameter has a significantly positive correlation with the longitude,annual mean temperature and annual precipitation(P=0.05).It is suggested that the phenotypic traits of S.pohuashanensis seedling vary richly among provenances or among pedigrees within provenances and possess obvious genetic differentiations.In which,the variance from pedigrees within provenances is the main source of the phenotypic variation.A primary opinion is that the variation of phenotypic traits of S.pohuashanensis is a double pattern of latitude and longitude,in which the latitude plays the major role.