| Loropetalum chinense vai.rubrum belongs to Hamamelidaceae, which is defined as a variety of L.chinense in morphology. It's natural distribution ranges from the east of Hunan province in the middle of Luoxiao Mountains. It's an evergreen shrub with many favourable landscape characteristics. It produces abundant attractive flowers (red-purple group) in spring and autumn, and some accessions even can yield a few flowers in summer. It is fast-growing and tolerant to disease and insects. Many L. chinense var. rubrum accessions have been introduced to North America since the 1980s, selection and registration of cultivar have been carried out since then. However in China, the study on Lchinense var.rubrum is still in primary stage. In recent years, with the rapid introduction and commercialization of Lchinense vai.rubrum, there comes many confusion concerning the identity of cultivars.In this study, the morphological traits of 21 accessions of Lchinense var.rubrum were investigated in spring, autumn, summer and with 2 more accessions in autumn. Clustering analysis with Average Distance was processed for the main traits of leaf and flower using DPS (Data Processing System). Random amplified polymorphic DNA (RAPD) reactions were performed on the total 27 samples including 23 accessions mentioned above (NO.1-21, 26~27),1 accession of Lchinense var.semper-rubrum (No.22, another variety of Lchinense}, 1 accession from a branch with green leaf white flower on a plant which has the similar morphological trait with No.l (No.25), and 2 accessions of Lchinense (No.23~24).The comparision of morphological investigation results indicated that the number of the flowering accessions and the number of flowers of Lchinense var.rubrum in spring were more than those in autumn. Only one accession (No. 13) yielded several flowers in summer. Some accessions had the same or similar color of leaf and/or flower in spring, and so was it in autumn. Only No. 13 and No. 15 had same color in spring and in autumn, while others showed slight different in color in springyielded several flowers in summer. Some accessions had the same or similar color of leaf and/or flower in spring, and so was it in autumn. Only No. 13 and No. 15 had same color in spring and in autumn, while others showed slight different in color in spring and in autumn.The clustering analysis on the spring morphological chatactreistics depicted 4 groupings of the 21 accessions. There were similarities within each group especially for leaf and/or flower color. Generally, the group formed firstly due to the similarity in leaf color, including the color of the face and the back of young leaf, and the color of mature leaf. The accessions with similar flower color seemed to form subgroups within a group.The 27 samples were separated into 5 main groups according to Unweighted pair-group mathematic analysis(UPGMA) clustering based on the RAPD data. These groups did not correlate closely with leaf or flower color, but there were similarities for leaf and/or flower color in some subgroups. Two accessions ofL.chinense showed closely with 2 small-leaf accessions of L.chinense vai.rubrum. The distances between L.chinense and L.chinense vai.semper-rubrum was closer than that between L.chinense and L.chinense var.rubrum.The UPGMA dendrogram illustrated close relationship between No.l and 25; 18 and 21; 23 and 24; 4, 26 and 17; 12, 27 and 15 etc, which suggested that UPGMA results were in accordance with morphological data among these subgroups, while others could not. The RAPD data indicated that the distance among accessions with distinct morphological traits could be very short. Conversely, the accessions which were quite distantly related could be indistinguishable in morphological traits.This study indicated that there was abundant genetic diversity in L.chinense . vai.rubrwn. It should be possible to improve the valuable ornamental traits of L.chinense var.rubrum by selection and introspecific crosses.
|
PDF Full Text Request