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Quantitative Taxonomy of Osmanthus fragrans Cultivars in Jingzhou
Journal of Horticulture

Journal of Horticulture
Open Access

ISSN: 2376-0354

Rapid Communication - (2019) Volume 6, Issue 2

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 »

Abstract

This investigation had been implemented for checking Osmanthus fragrans Resources. In this paper, 29 classified characters were selected based on our preliminary research foundation of O. fragrans in Jingzhou city parks, then O. fragrans quantitative classification of 24 cultivars was carried out by SPSS analysis. The results showed principal component contribution rate was scattered, which is not an ideal method for quantitative classification of O. fragrans cultivars. The method of Walder was the best among seven clustering methods. The clustering results showed that there was a long relationship between autumn Osmanthus and Asiaticus Group. In addition, flowering season, flower color and fertility were very important for O. fragrans cultivars classification. The evolution of O. fragrans petals color might be complex and multi-way. The O. fragrans cultivars classification should not be too entangled with their color, but mainly based on flowering date. The comprehensive evaluation of inflorescence type, flower color, leaf color and other morphological characteristics played necessary reference role for the traditional variety classification method and the modern quantitative classification method.

Keywords

Osmanthus fragrans; Quantitative classification; Principal component analysis; cluster analysis

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.

Number Cultivars name Investigation sites Number Cultivars name Investigation sites
1 Sijigui MY 13 Taoyehuang SG
2 Dahua Zaoyingui MY 14 Jiaorong SG
3 Zhaoxia SG 15 Juye Sijigui SG
4 Chi Dangui SG 16 Chuizhihuang ZS
5 Zhusha Dangui SG 17 Yinsu ZS
6 Zidangui SG 18 Dayehuang Jingui ZS
7 Chenghong Dangui SG 19 Daye Yingui ZS
8 Wuhan Qiancheng SG 20 Zigeng ZS
9 Jinqiugui SG 21 Xiaoye Sijigui ZS
10 Hongshizi SG 22 Duanbingzi Yingui ZS
11 Boye Jingui SG 23 Jiangnanliren BJ
12 Daye Sijigui SG 24 Liuyesugui BJ

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.

Number Traits Coding type Coding value
1 Crown tightness Many dense crown(0);middle(1);Sparse crown(2)
2 Branchlet growth Many strong(0);middle(1);slim(2)
3 Annual branch length Number Short(0):≤8cm;middle(1):9-15cm;long(2):≥16cm
4 Leaf type Two single(0);doubles(1)
5 Leaf shape Many Long oval(0);oval (1);wide oval (2);Obovate-oval (3);ovate-oval (4)
6 Leaf texture Two Leathery(0);Thick leathery(1)
7 Leaf vein Two Obvious(0);less obvious(1)
8 Leaf margin Many Entire leaf(0;entire leaf or little serrate(1;exceed 1/2 serrate(2);serrate(3)
9 Edge curvature Many flat(0);slightly ripple (1);ripple(2)
10 Leaf involute Many flat(0);slightly involute(1);V shape(2)
11 Leaf apex shape Many acute(0);acuminate(1);mucronate(2);trailing edge(3)
12 Leaf base shape Many circular(0);broad wedge(1);wedge(2);Leaf base extension(3)
13 Leaf gloss Many glossiness(0);little gloss(1);gloss(2)
14 Leaf length Number short(0):6-7cm;middle(1):8-12cm;long (2):17-20cm
15 Leaf width Number Narrow(0):2.5-3cm;middle(1):3-4cm;wide (2):≥7cm
16 Lateral vein Number Few(0):≤7pairs;middle(1):7-10 pairs;many(2):≥10 pairs
17 Petiole length Number short(0):≤7mm;middle(1):7-12mm;long(2):≥12mm
18 Blossom season Two everblooming (0);Autumn(1)
19 Blossom period Many Early(0):Mid-late August-early September;middle(1):Mid-September to Mid-October;late(2): in Mid-October and later
20 Peduncle Two yes(0);no(1)
21 Peduncle color Many Yellow-green (0);apex green and base red (1);red or Purplish red (2)
22 Petal shape Many Narrow (0);Obovate (1);Obovate oval (2);broad rounded (3)
23 Petal morphology Many flat(0);Oblique(1); slightly involute(2);involute(3);Tai Ge(4)
24 Petal color Many Creamy yellow(0);orange yellow(1);light orange(2);orange-red(3);golden yellow (4);yellow (5);light yellow (6);dark yellow (7);yellow-white(8)
25 Ovary development Many Development(0);Development but no fruit (1);degeneration(2)
26 Flower numbers Number few(0):≤5 ;middle(1):6-7;many(2):≥8
27 Peduncle length Number short(0):<7mm;middle (1):7-11mm;long (2):>11mm
28 Flower diameter Number small(0):<7mm;middle(1):7-9mm;big(2):>9mm
29 Fruit shape Many No (0);egg shape(1);ellipsoid(2);sub-globose(3)

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).

Component Initial eigenvalue Extracting Square Sum of Load
Total Variance Proportion Accumulate (%) Total Variance Proportion Accumulate (%)
1 4.018 14.348 14.348 4.018 14.348 14.348
2 3.564 12.729 27.077 3.564 12.729 27.077
3 3.534 12.621 39.697 3.534 12.621 39.697
4 2.826 10.091 49.789 2.826 10.091 49.789
5 2.359 8.426 58.215 2.359 8.426 58.215
6 2.064 7.370 65.585 2.064 7.370 65.585
7 1.821 6.502 72.087 1.821 6.502 72.087
8 1.370 4.894 76.981 1.370 4.894 76.981
9 1.233 4.402 81.383 1.233 4.402 81.383
10 1.009 3.602 84.985 1.009 3.602 84.985

Table 3: Interpretation of total variance of partial traits.

  Traits Component
1 2 3 4 5 6 7 8 9 10
Crown dense .322 -.440 .277 .351 .354 -.239 -.075 -.030 -.281 .161
Branchlet growth .099 .905 .084 -.131 -.010 -.229 .024 -.109 -.037 .022
Annual shoot length .690 .380 -.048 .328 .110 .276 .017 .020 .077 -.050
Leaf type -.832 .095 .280 -.266 .095 .266 -.152 -.004 -.037 -.112
Leaf shape -.575 .096 -.052 .243 .214 -.222 -.052 .064 .307 .466
Leaf texture -.072 -.584 -.245 .241 -.040 .249 .428 .311 .216 -.240
Leaf vein -.129 -.461 -.250 -.466 .055 -.207 .407 -.244 .202 .154
Leaf margin .350 .516 .022 -.428 .157 -.154 .135 .100 .008 -.322
Edge curvature .029 -.002 .441 .297 .287 -.010 -.106 .251 -.618 -.011
Leaf involute -.210 .015 .367 .265 .545 -.039 .398 .268 .077 -.145
Leaf base -.258 -.317 -.477 .057 -.060 -.569 .082 -.241 -.144 -.028
Leaf apex .168 .084 .573 -.198 -.257 -.286 .303 -.137 -.086 .185
Leaf gloss -.170 .498 -.419 .082 .298 .499 -.019 -.107 .053 .257
Leaf length .267 -.102 .758 -.021 -.358 .216 .217 -.114 .144 .144
Leaf wide .267 -.102 .758 -.021 -.358 .216 .217 -.114 .144 .144
lateral vein pairs .268 .140 -.261 .247 -.051 .576 -.172 -.441 -.087 .112
Leaf petiole -.117 .143 .552 .577 .246 .047 -.082 .144 .217 .085
Flowering season .832 -.095 -.280 .266 -.095 -.266 .152 .004 .037 .112
Flowering period .637 -.012 -.328 .464 .061 -.142 .125 .030 .115 .070
Peduncle color .071 .723 -.124 .052 -.054 -.081 .462 .154 .163 -.209
Petal shape .218 -.604 -.109 -.141 .219 .254 -.180 .331 .290 .047
Corolla shape -.106 -.156 -.382 .174 -.607 .467 .192 .099 -.262 -.118
Petal color .109 .343 -.354 .080 -.302 -.255 -.450 .389 .181 .168
Ovary development -.547 .104 .076 .645 -.319 -.211 .025 -.078 .084 -.223
Flower numbers per Inflorescence .070 -.025 -.012 .017 .709 .102 .067 -.516 .214 -.201
Peduncle length .263 -.094 .389 -.330 -.167 -.074 -.577 .049 .358 -.217
Corolla diameter .327 -.296 .113 .250 .020 -.163 -.395 -.283 .041 -.357
Fruit shape .451 -.076 -.083 -.674 .353 .118 .049 .268 -.197 .108

Table 4: Partial trait component matrix.

horticulture-Jingzhou-city

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

horticulture-Clustering-results

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.

horticulture-cultivars

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

Author Info

Sun Taoze, Dongling L and Mu Hongna*
 
College of Horticulture and Gardening, Yangtze University, Jingzhou, 434025, China
 

Citation: Taoze S, Dongling L, Hongna M (2019) Quantitative Taxonomy of Osmanthus fragrans Cultivars in Jingzhou. J Hortic 6:258. doi: 10.35248/2376-0354.19.06.258

Received Date: May 16, 2019 / Accepted Date: May 30, 2019 / Published Date: Jun 07, 2019

Copyright: © 2019 Taoze S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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