Journal of Horticulture
Open Access

Quantitative Taxonomy of Osmanthus fragrans Cultivars in Jingzhou

Sun Taoze, Dongling L and Mu Hongna^{* *}Correspondence: Mu Hongna, College of Horticulture and Gardening, Yangtze University, Jingzhou, China, Tel: 8615927891434, Email:

Author info »

Introduction

Osmanthus fragrans is a species of Oleaceae family. It is one of the well-known flowers in China for its wonderful meaning, pleasant aroma and good economical values in food, medicine, industry and landscape architecture [1-5]. Because the origin and distribution center of O. fragrans locates in China, there are plenty of cultivars, which composed of colorful and fragrance cultivars [6] and color-leaves [7]. Different characteristics for every Cultivars Group. Luteus Group is more suitable for food processing, nutrition and health products development. Asiaticus Group plays vital important role in offsetting flower gap in winter. It was necessary to find out the current situation of O. fragrans cultivars in local areas, which had theoretical and practical significance for improving the effect of urban greening and beautification.

Quantitative taxonomy, as a frontier discipline, has developed rapidly in recent years with the development of computer technology, especially with the emergence of various statistical software. Quantitative taxonomy has gradually become an important method for studying variety classification [8,9]. The study on quantitative classification of O. fragrans cultivarshad great significance to the improvement of O. fragrans classification system in future [10-12].

Materials and Methods

This research was carried out based on the tradition classification of O. fragrans in Jingzhou [13]. All the materials were distributed in Mingyue Park, Sanguo Park, Zhongshan Park and Binjiang Park respectively. All materials, O. fragrans tree, were listed in Table 1.

Table 1: Cultivar names of Osmanthus fragrans in Jingzhou.

Selection and coding of classified characters

Through the observation and analysis of O. fragrans cultivars, 29 relatively stable traits reflecting the differences of characteristics among cultivars were selected as quantitative classification traits. Five of them were binary traits (abbreviated as "two"), 16 were polymorphic traits (abbreviated as "many"), and eight were continuous numerical traits (abbreviated as "number"). The detailed information was presented in Table 2.

Table 2: The characters and codes of Osmanthus fragrans cultivars.

Statistics and analysis

The principal component analysis and cluster analysis had been carried out by SPSS 25.0 software according to those selected 29 classical traits of O. fragrans. As for cluster analysis methods, the Wald method and Square Euclidean distance had been chosen, and then operations were carried out. Intergroup connection, Intragroup connection, nearest element, Farthest neighbor element, Centroid clustering and Median clustering were utilized as reference. Next comparison and analysis had been implemented between the former and the latter.

Results and Analysis

After the standardization of the original data, the total variance explanations of 29 principal components of traits (some of the principal components involved in the analysis are listed in Tables 3 and 4) and the tree clustering maps of Q-type clustering of 26 traits are obtained by SPSS software operation (Figures 1 and 2).

Table 3: Interpretation of total variance of partial traits.

Table 4: Partial trait component matrix.

Figure 1: The Walder Cluster Map for 24 Osmanthus fragrans cultivars in Jingzhou city

Figure 2: Other 6 kinds Clustering results for 24 Osmanthus fragrans cultivars in Jingzhou city

Results of principal component analysis

10 principal components were extracted from the principal component analysis, with a cumulative contribution rate of 84.985% (Table 3). This result illustrated that the contribution rate of principal components was relatively scattered, and the principal component analysis method was not feasible in the study of quantitative classification of O. fragrans. However, it also showed the characteristics diversity and the complexity of O. fragrans cultivars. It also showed that O. fragrans cultivars were evolving in many directions, which resulted in different branching groups. The principal component analysis method provided a quantitative basis for the evolution of O. fragrans.

In addition, the contribution rates of the top four principal components were 14.348%, 12.729%, 12.621% and 10.091% respectively Tables 3 and 4. Among them, flowering season (0.832), annual branch length (0.690), flowering period (0.637), and other characteristics were more important composition of the first principal component. Branchlet growth (0.905), pedicel color (0.723), leaf margin (0.516) had more contribution to the second principal component than others. Similarly, traits with higher contribution to other principal components can be identified also. According to the results of principal component analysis, when classifying O. fragrans cultivars, priority should be given to the characteristics of flowering period, pedicel color, petal shape, petal color, leaf shape, leaf texture and leaf gloss.

Results of cluster analysis

Although the same data, the analyzed outcomes would be varied in pace with different clustering methods. Before clustering data analysis had been done, clustering analysis methods should be compared and taken a decision [10]. This paper compares intergroup join, intra-group join, nearest neighbor element, farthest neighbor element, centroid clustering, median clustering and Walder method (Figures 1 and 2). Cluster map reflects the distance of the genetic relationship of sample materials, the earlier they gather together, the closer the genetic relationship. From the graph, we can see that different clustering methods have different results.

We chose the Walder method, which had the best clustering effect for analysis, after comparing with all the others clustering graph illustrated in Figure 3. Twenty-four O. fragrans cultivars were grouped into five groups when L1 (lambda=16.992) was taken as the binding line (Figure 1). The first group consisted of two cultivars of Asiaticus Group (‘Citrus leaf Sijigui’, ‘Big leaf Sijigui’); the second group consisted of three cultivars of Asiaticus (‘Sijigui’, ‘Xiaoye Sijigui’, ‘Dongxianghong’); the third group consisted of purple stalks clustered into a single group, the fourth group consisted of two Aurantiacus Group (‘Seed Dangui’, ‘Zhao Xia’) and one Albus Group (Short stalk Seed Silver Gui); the remaining 15 cultivars included Luteus Group (6) and Albus Group (4) and Aurantiacus cultivar groups (5) were clustered into the fifth group.

Figure 3: Identified Osmanthus fragrans cultivars in Jingzhou (illuminated some cultivars)
1 Daye Yingui, 2 Jiangnanliren, 3 Liuyesugui, 4 Sijigui, 5 Zhaoxia, 6 Chi Dangui, 7 Zidangui, 8 Chenghong Dangui, 9 Dahuazaoyingui, 10 Dongxianghong, 11 Jinqiugui, 12 Hongshizi, 13 Boye Jingui, 14 Taoyehuang, 15 Juye Sijigui, 16 Houban Yingui, 17 Yinsu, 18 Dayehuang Jingui.

When L2 (lambda=18.031) was taken as the binding line, 24 O. fragrans cultivars were clustered into four groups. The first group was Asiaticus cultivar group, which included 5 Asiaticus cultivars. The second, third and fourth groups are the third, fourth and fifth groups when L1 is chosen as the dividing line. When L3 (λ = 24.991) was taken as the binding line, 24 O. fragrans cultivars were clustered into two groups. The first group consisted of five cultivars of Asiaticus, and the second group included 19 cultivars such as ‘Jinqiugui’, ‘Red Cross’ and ‘Jiangnan Liren’.

Based on the above analysis results, it can be concluded that the genetic relationship among Autumn Osmanthus (Jingui, Dangui and Yingui) was more close than between Asiaticus Group and Autumn Osmanthus. At the same time, on the three lambda, different blossom seasons of O. fragrans were aggregated separately, which reflected that took the flowering season as a high-level criterion for classification of O. fragrans cultivars is more appropriate.

Conclusion

The characters selected by the system clustering were quantified according to certain criteria, which avoided the influence of subjective factors to a certain extent and makes up for the shortcomings of traditional morphological classification. Based on the quantitative classification of O. fragrans cultivars in Jingzhou Park, the feasibility of principal component analysis (PCA) of O. fragrans cultivars was discussed. The significance of florescence, pedicel color, petal shape and other characteristics was discussed. The genetic relationship among the cultivars was discussed by Q-type clustering, and some useful conclusions were obtained.

(1) Although the quantitative classification method based on phenotypic traits has limitations in practical application, such as strong subjectivity in the selection and coding of traits, the results obtained by different treatment methods are generally different. However, the method can synthesize various traits from different sources, a general classification system can be obtained, which can be compared with the traditional classification method. The two classification methods can do complements each other.

(2) The evolution of O. fragrans flower color should be complex and multi-way. Besides the evolution direction of "Albus (white) - Luteus (yellow) - Aurantiacus (orange yellow, orange red)", there should be other ways. Therefore, the classification of Osmanthus cultivars should not be too entangled with flower color. We conclude flowering stage, and comprehensive evaluation of inflorescence type, flower color, leaf color and other morphological characteristics should be taken into account mainly, while encounter classification of O. fragrans cultivars.

Acknowledgment

Thanks for the assistance of Zhao Fei, Shi Tingting and Liao Lulu in the investigation process. Thanks for the support of the Doctoral Research Initiation Fund of Yangtze University (801190010129).

References

1. Yang XL, Song JN, Zhao F, Wang NG. Effects of cold storage on major nutrients of five Osmanthus fragrans cultivars. Southwest China J Agri Sci. 2014;27(6):2720-2722.
2. Ye C, Zhang L, Wang P, Shang YZ, Wang LM. Comparative study on contents of amino acids and trace elements of 4 Osmanthus fragrans Cultivars. J Food Ind. 2013;34(6):203-205.
3. Sheng YZ, Yu LJ, Wang LM. Screening and evaluation of natural food preservatives. Food Sci Technol. 2009;34(8):204-207.
4. Yin W, Yu Y, Ma QL, Chen T, Zhang GS. Study on chemical constituents and antitumor activities of leaves of Osmanthus fragrans. J Tropical and Subtropical Botany. 2018;26(2):178-184.
5. Shi TT, Yang XL, Wang LG. Study on the aroma component emission pattern of Osmanthus fragrans ‘Boye Jingui’. J Nanjing Forestry University (Natural sciences Edition). 2018;42(2):97-104.
6. Zang DK, Xiang QB, Liu YL. Notes on cultivar classification in Osmanthus. Scientia Silvae Inicae. 2006;42(5):17-21.
7. Yu L, Li JH, Bai WF, Nie DL, Wu SZ, Yi JX. A New Osmanthus fragrans cultivar Caihong. Acta Horticulturae Sinica. 2018;45(5):207-208.
8. Liu LC, Xiang QB. Study on numerical taxonomy of sweet osmanthus cultivars. J Fujian College of Forestry. 2004;24(3):233-236.
9. Tang DQ. A study on numerical classification of the cultivars of sweet osmanthus (Osmanthus fragrans (thunb.)lour.). J Nanjing Forestry Univ. 1998;22(1):37-42.
10. Duan YF, Wang XR, Lliang LL, Xiang QB, Yi XG. A numerical classification of the sweet osmanthus cultivars in xian’ning of Hubei Province. J of Hubei Univ for Nationalities (Natural Science Edition). 2010;28(3)289-293.
11. Zeng MY. Study on quantitative classification of Osmanthus fragrans cultivars in Sichuan province. South China agriculture. 2009;3(2):68-70.
12. Zhao XM, Chen ZF. Studies on the numerical taxonomy of Osmanthus fragrans Lour cultivars in Wuhan. J Hubei Institute for Nationalities. 1998;6:11-15.
13. Sun TZ, Zhao F, Li DL, Mu HN. Variety identification and landscape application of Osmanthus fragrans in Jingzhou City. J Hortic. 2019;6(1):1-4.