Study on Leaf Phenotypic Variation of a Sympatric Population of Castanea mollissima and C.henryi

The phenotypic variation among the plants of a sympatric population composed of 169 Castanea mollissima Bl.and 281 C.henryi Rehd.& Wils.in Hubei province Zigui county was investigated based on 20 leaf morphological characters.According to pubescence on the abaxial surface of the leaf and on the petiole,and leaf marginal shape,18(4%) of the 450 sampled individuals were assigned to intermediate types between the two species.The stepwise discriminant analysis(SDA) based on 17 numerical characters indicated that 7 and 11 individuals with intermediate morphologies were classified to C.mollissima and C.henryi respectively.There were significant differences between C.mollissima and C.henryi on the leaf morphological characters,which led to a high accuracy of identification(93%).Therefore,the discriminant functions with 8 numerical characters were effective in the distinguishing of C.mollissima and C.henryi.In the principal component analysis(PCA),three principal components were constructed based on 20 characters,with the contributory ratio of the PC1 and PC2 of 53.5% and 18.7%,respectively,and the cumulative contributory ratio of 72.2%.In the scatter diagram for PC1 and PC2,6(1/3) individuals with intermediate morphologies were located in the contact zone between C.mollissima and C.henryi,which may provide morphological evidence for hybridization between C.mollissima and C.henryi.