Analysis of Qualitative and Quantitative Traits to Identify Different Chinese Jujube Cultivars

Article information

Plant Breed. Biotech.. 2019;7(3):175-185
Publication date ( electronic ) : 2019 September 01
doi : https://doi.org/10.9787/PBB.2019.7.3.175
Division of Forest Special Products, National Institute of Forest Science, Suwon 16631, Korea
*Corresponding author: Jae-Ik Nam, minesilhouette@gmail.com, Tel: +82-31-290-1099, Fax: +82-31-290-1050
received : 2019 April 24, rev-recd : 2019 May 20, accepted : 2019 May 27.

Abstract

Chinese jujube (Ziziphus jujuba Mill.) is highly resistant to environmental stress and can be easily cultivated, thus many jujube cultivars are being developed. However, the same cultivars had been cultivated with different names. Thus, systematic management is required to protect the intellectual property of different varieties. To aid systematic control of jujube cultivars, this study presents efficient markers for distinguishing cultivars through identification of morphological characteristics and relationships among 25 jujubes. Among 10 qualitative characteristics, flowering time, fructification time, presence of thorns, and shape of fruit were found to be useful traits for the cultivar identification. In the results of principal component analysis, 3 principal components (PC) represented 73% for the total variations. PC1 showed high positive correlations with fruit–related characteristics and PC2 formed a cluster with leaf-related characteristics. Therefore, the differences in fruit and leaf were identified as useful traits for the cultivar identification. According to the results of cluster analysis, which largely divided cultivars into 4 clusters, Sour jujube 2, with smaller fruits and leaves, was separated first. Cluster II included Chinese cultivars with large fruit sizes, such as Dalizao, Dabailing, Damaya, and Daguazao. Three Korean cultivars were grouped with Bokjo, Panzao, Zanhuangdazao, and Jinsi No. 3, and the remaining 13 cultivars formed a separate cluster.

INTRODUCTION

Chinese jujubes (Ziziphus jujuba Mill.) belong to the Rhamnaceae family (Liu and Cheng 1995) and they have been cultivated in Europe, Africa and Asia. They are recognized for their usefulness along with Indian jujube (Z. mauritiana Lam.) (Adams et al. 1978; von Maydell 1986). Jujubes are highly resistant to environmental stress and can be easily cultivated. Owing to the high levels of vitamin A, B1, B2, C, and flavonoids in fruits, many cultivars have been developed in South Korea, China, Japan, and Russia (Dagar et al. 2001; Hebbara et al. 2002). There were 11 jujube cultivars in 600 BC, increasing to 72 cultivars in the 1300s, and at least 700 cultivars were reported in 1993 (Qu and Wang 1993). However, Liu and Cheng (1995) summarized that there are 170 cultivars, indicating that the same cultivars had been cultivated with different names because of the frequent exchange of plant material among different cultivation areas, and the lack of cultivar history documentation.

Trade-Related Aspects of Intellectual Property Rights (TRIPs) and the International Union for the Protection of New Varieties of Plants (UPOV) of the World Trade Organization (WTO) request a systematic control of cultivars to protect the rights of breeders and intellectual property of varieties. Given that jujubes are easily traded by asexual propagation, it is predicted that any issue related with intellectual properties would cause significant economic damages.

Many markers have been applied to identify cultivars and analyze their relationships, and important traits have been selected by classifying organ characteristics. Phenotypic markers, with no use of special instruments or techniques, aid observation and comparison of growth, symptoms, and characteristics between populations or individuals. In earlier times they were used for purity testing and observation of chlorosis in seedlings. Thereafter, methods to document and analyze mutants were developed to classify lines or varieties (Sneath and Sokal 1973; Sneath 1995). However, methods using phenotypes have issues such as differences in values depending on the evaluated parts (Hedren 2002) and evaluation variations, even in the same individual plant, depending on environmental factors. Therefore, a sufficient number of samples and application of statistical methods are required to have objective markers (Smith and Smith 1992; Pratt and Clark 2004).

To aid systematic control of jujube cultivars, this study presents efficient phenotypic markers for distinguishing Korean and Chinese cultivars through identification of morphological characteristics and relationships among 25 cultivars in South Korea and China. Based on the ‘Test Guideline (TG) for Common jujube’ that has been used for registration of jujube varieties, characteristics that were expected to have variations between cultivars were added to analyze polymorphic information.

MATERIALS AND METHODS

Testing materials

This study used jujube plants that showed normal flowering and fructification among those maintained in the National Institute of Forest Science, which included a total of 25 varieties as follows: 23 jujube cultivars, including Korean cultivars (Mudeung, Wolchul, and Geumseong), Korean native varieties (Bokjo, Boeundaechu and Chuncheon 7) and Chinese cultivars (Dalizao, Huizao, Pozao, Panzao, Zanhuangdazao, Zhongyangmuzao, Sandonglizao, Dabailing, Damaya, Daguazao, Jinsixiaozao, Jinsi No. 3, Jinsi No. 4, Yuanling No. 1, Yuanling No. 2, Xiaolizao, and Dongzao), as well as two related species of Sour jujube (Z. acidojujuba C.Y. Cheng & M.J. Liu) that were classified as either variant or wild type (Table 1).

Cultivars name and their source used in this study.

Investigation of morphological characteristics

According to the ‘TG for Common jujube’, 10 qualitative traits and 15 quantitative traits on growth, leaves, fruits, and stones were investigated for 3 years starting in 2013 (Table 2 and 3). Growth characteristics were investigated in 5 replications for each cultivar. For bud burst time and flowering time, the periods of leaf formation and flowering were divided into early (3), mid (5), and late (7) times for 2 months from the end of April. For fructification time, post ripe stage time, when 2 out of 3 fruits were pigmented around September, was divided into early (3), mid (5), and late (7) times. Spike formation was categorized depending on spikes were present (1) or absent (0) in annual branches.

List of 10 qualitative characteristics of jujube cultivars for phenetic analysis in this study.

List of 15 quantitative characteristics of jujube cultivars for phenetic analysis in this study.

Leaf, fruit, and stone traits were evaluated 30 times each in 5 replications per cultivar using fruit branches from the end of September to the beginning of October. Leaf colors on the top and bottom sides were coded by comparison to the Royal Horticulture Society (RHS) Color Chart.

Qualitative traits were classified according to the ‘TG for Common jujube’. Leaf shape was divided into elliptical (3), oval (5), and oblong (7), and serra shapes classified as entire (1), serrate (2), and biserrate (3). Fruit shape was classified into round (1), round oblate (2), oval (3), oblong (4), and elliptical (5), and stone shape was divided into round (3), ovate (5), and fusiform (7).

Statistical analysis

To find morphological characteristics of jujube cultivars, the most frequently observed traits were presented as qualitative traits, whereas variance analysis was performed for quantitative traits, followed by the comparison of mean values.

Principal component analysis (PCA) was performed to analyze relationships between cultivars. Eigenvalues, contributions of principal components to the total variation, and contributions of traits in principal components were calculated, followed by production of biplots based on the first and second principal component scores. Cluster analysis was applied on principal component scores and was presented in a dendrogram with the Unweighted pairgroup method using arithmetic averages (UPGMA). All statistical analyses on data were performed in SPSS ver. 18.0.

RESULTS

Qualitative characteristics of jujube cultivars

There was no clear difference in bud burst time; all cultivars started leaf unfolding within 1 week from the end of April to the beginning of May. On the other hand, some cultivars showed differences in flowering and fructification times. Dalizao, Sandonglizao, Xiaolizao, and Dongzao had delayed flowering and fructification by more than 1 week compared to other cultivars (Table 4). There were clear differences in spike formation depending on cultivars. Annual branches of most cultivars had no spikes, whereas Huizao, Panzao, Jinsixiaozao, Jinsi No. 4, Sandonglizao, and Xiaolizao, along with Sour jujube developed sharp spikes (Table 4). As for fruit shapes, some cultivars showed unique shapes, which seemed to be useful for identification as markers (Table 4). While oblong shape was general, Daguazao, Dabailing, and Yuanling No. 2 had large elliptical shapes and Damaya showed a unique shape with protrusion at the bottom (Fig. 1). The 4 traits related with leaves were mostly found to have either single traits or severe variations within individuals, so that they were considered inappropriate for using as markers to identify cultivars (Table 4).

Representative characteristics of 25 jujube cultivars in the related qualitative traits.

Fig. 1

Morphological variability of fruits in various jujube cultivars.

Quantitative characteristics of jujubes cultivars

Fifteen quantitative traits were subjected to variance analysis, followed by comparison for each category using Duncan’s test. As a result, sizes of leaves, fruits, and stones were identified and useful information for identification between jujube cultivars and Sour jujube and between Korean cultivars and two Chinese apple jujube cultivars (Daguazao and Dabailing) were obtained (Table 5 and 6).

Mean values of leaf related quantitative characteristics in 25 jujube cultivars.

Mean values of fruit and seed related quantitative characteristics in 25 jujube cultivars.

Twenty-two jujube cultivars averaged 57.87 mm in leaf length, 28.89 mm in leaf width, 42.91 mm in terminal leaf length, and 20.24 mm in terminal leaf width, whereas Sour jujube averaged 37.06 mm in leaf length, 18.88 mm in leaf width, 26.51 mm in terminal leaf length and 12.48 mm in terminal leaf width, showing that Sour jujube could be distinguished by leaf size. In addition, jujube cultivars averaged 34.93 mm in fruit length, 27.09 mm in fruit width, and 12.50 g in fruit weight, whereas Sour jujube averaged 13.37 mm in fruit length, 11.83 mm in fruit width, and 1.07 g in fruit weight, showing that they were clearly distinct.

Korean cultivars and Chinese apple jujube cultivars were compared to find differences. Geumseong, Mudeung, and Wolchul averaged 65.62 mm in leaf length, 34.79 mm in leaf width, 52.36 mm in terminal leaf length, and 25.96 mm in terminal leaf width. In contrast, Daguazao and Dabailing averaged 58.44 mm in leaf length, 28.47 mm in leaf length, 38.51 mm in terminal leaf length, and 17.52 mm in terminal leaf width, indicating that two Chinese cultivars were smaller than Korean cultivars. The difference was more obvious in fruit characteristics. Fruits of Korean cultivars were oblong with 36.95 mm mean fruit length, 26.53 mm mean fruit width, and 11.20 g mean fruit weight, whereas Daguazao and Dabailing had round fruits with 39.66 mm, 37.16 mm, and 25.54 g, respectively, being more than 2 times heavier.

Principal component analysis (PCA)

To investigate relationships among jujube cultivars, contribution of principal component to eigenvalues and total variations were calculated using 15 quantitative traits as variables. Traits that had at least 1.0 eigenvalue were extracted for calculation. Regarding characteristics obtained by PCA, the eigenvalue for the first principal component (PC1) was 5.76, which contributed 38.4% to the total variance, while those of the second principal component (PC2) and the third principal component (PC3) were 3.94 (26.2%) and 1.28 (8.6%), respectively, so that the 3 principal components contributed 73.2% to the total variance (Table 7).

Principal component analysis based on 15 quantitative characteristics for 25 jujube cultivars.

In the correlation analyses between principal components and morphological characteristics, PC1 showed high positive correlations with fruit–related characteristics such as fruit weight (0.940), flesh index of fruit (0.933), and fruit width (0.903), and PC2 formed a cluster with leaf-related characteristics such as terminal leaf width (0.898), terminal leaf area (0.845), terminal leaf length (0.816), leaf width (0.786), and leaf area (0.759). For PC3, petiole length (0.865), leaf length (0.627), and terminal petiole length (0.621) were identified as major traits (Table 8).

Eigenvectors associated with the eigenvalues obtained from principal component analysis for 15 quantitative characteristics on 25 jujube cultivars.

Cultivars were plotted in a 2-dimensional space using PC1 and PC2 as axes. Korean cultivars, including Mudeung (K2), Wolchul (K3), and Geumseong (K4), were localized on the right side of the first axis along with Bokjo (KV1), Panzao (C9), and Zanhuangdazao (C10). In contrast, Chinese cultivars such as Dabailing (C11) and Daguazao (C13) were on the upper left part of the biplot, whereas Sour jujube 2 (RS25) was independently located at the lower left side of the biplot (Fig. 2).

Fig. 2

Scattered diagram of 25 jujube cultivars based on the principal component 1 and 2 variables for 15 morphological characteristics. Major cultivated jujube cultivars in Korea were grouped with two Chinese cultivars in the red circle. 2 Chinese jujube cultivars in the green circle were commonly known as apple jujube. The blue circle, related species Sour jujube was completely separated from cultivated jujube cultivars.

Cluster analysis

Scores calculated from PCA were standardized as new variables, followed by cluster analysis of 25 jujube cultivars, which were largely divided into 4 clusters. Sour jujube 2 (RS25) that had smaller fruits and leaves was separated first. Cluster II included Chinese cultivars with large fruit sizes, including Dalizao (C6), Dabiling (C11), Damaya (C12), and Daguazao (C13), and Cluster III had Bokjo (KV1), Mudeung (K2), Wolchul (K3), Geumseong (K4), as well as Panzao (C9), Zanhuangdazao (C10), and Jinsi No. 3 (C19). The remaining 13 cultivars and individuals formed a cluster, which included 10 Chinese cultivars and various individual cultivars such as Boeundaechu (KV5), Chuncheon 7 (KV23), and Sour jujube 1 (RS24) (Fig. 3).

Fig. 3

Dendrogram for cluster analysis of 25 jujube cultivars based on quantitative morphological data.

DISCUSSION

Some morphological characteristics showed significant differences among cultivars under the same conditions, making them useful characteristics for cultivar identification. Among qualitative traits, jujube cultivars could be identified using presence or absence of spikes and fruit shape.

Plants defend themselves from herbivores using morphological mechanisms to change densities of spikes, stellate hairs, and branches and chemical mechanisms that increase secondary metabolites (Karban and Myers 1989; Haukioja 1990; Herms and Mattson 1992; Hartley and Jones 1997). Such mechanisms have been reported to be different between individual plants and variable depending on time and environmental stresses (Massei and Hartley 2000). Energy allocation to defensive mechanisms leads to growth retardation (Bazzaz et al. 1987) and an artificial intervention during cultivation can reduce energy allocation to defense mechanism resulting in increased selection for plants with high growth rates and yields (Small 1996; Rosenthal and Dirzo 1997; Jones 1998). In a study with olive tree wild types and cultivars, Massei and Hartley (2000) discovered that more herbivore browsing was associated with more investment on defensive mechanisms (i.e., spikes) and slower growth. In this study, spikes observed on annual branches were also a defensive mechanism. Considering that most plants in the genus Ziziphus, including Sour jujube, develop spikes, it seemed that spineless common jujube (Z. jujuba Mill. var. inermis) lines that consume less energy for defense during cultivation were generalized through artificial selection.

Bal (1992) reported that Indian jujube cultivars showed differences in the shape of fruit tips. Hence, it is thought that fruit shapes of jujubes could be used as main characteristics for identification of cultivars. Contrastingly, although nuclei transformed from the endocarp were related with fruit shape, they showed only little differences, making them difficult to measure in order to identify cultivars.

Cluster analysis found that the 15 quantitative traits were appropriate for identification of jujube cultivars. The three Korean cultivars together with Bokjo formed a cluster, while Boeundaechu belonged to another cluster. Hence, it is speculated that Mudeung, Wolchul, and Geumseong have a close relationship with Bokjo, while Bokjo and Boeundaechu have derived from different lines. As for Panzao, which was closely clustered with Korean cultivars, it was difficult to distinguish it using quantitative traits, but it showed differences in some qualitative traits. Therefore, it could be identified using comprehensive application of various characteristics. It would be possible to identify Korean cultivars and some Chinese cultivars using the investigated 25 morphological characteristics. However, differences in leaf-related characteristics were too small to apply to various cultivars, and it was considered difficult to apply fruit-related characteristics to seedlings. Furthermore, as metric traits are significantly affected by the plant’s growth environment and seasonal factors, a combination of molecular markers and phenotypic data is the best choice for genetic variability analysis.

References

Adams R, Adams M, Willens A, Willerns G. 1978. Dry lands, man and plants Architectural Press. London, U.K: p. 152.
Bal JS. 1992;Identification of ber (Ziziphus mauritiana L.) cultivars through vegetative and fruit characters. Acta Hortic 317:245–253.
Bazzaz FA, Chiarielli NR, Coley PD, Pitelka LF. 1987;Allocation resources to reproduction and defense. Bio-Science 37:58–67.
Dagar JC, Singh G, Singh NT. 2001;Evaluating forest and fruit trees for rehabilitation of semiarid alkali-sodic soils in India. Arid Land Res Manag 15:115–133.
Hartley SE, Jones CG. 1997. Plant chemistry and herbivory, or why the world is green. p. 284–324. Crawley MJ, editor. Plant ecology Blackwell. Oxford:
Haukioja E. 1990;Induction of defenses in trees. Annu Rev Entomol 36:25–42.
Hebbara M, Manjunatha MV, Patil SG, Patil DR. 2002;Performance of fruit species in saline-waterlogged soils. Karnataka Journal of Agricultural Sciences 15:94–98.
Hedren M. 2002;Patterns of allozyme and morphological differentiation in the Carex flava complex (Cyperaceae) in Fennoscandia. Nor J Bot 22:257–301.
Herms DA, Mattson WJ. 1992;The dilemma of plants: to grow or defend. Quart Rev Biol 67:283–325.
Jones DA. 1998;Why are so many food plants cyanogenic?. Phytochemistry 47:155–162.
Karban R, Myers JK. 1989;Induced plant responses to herbivory. Annu Rev Ecol Evol Syst 20:331–348.
Liu MJ, Cheng CY. 1995;A taxonomic study of the genusZiziphus. Acta Hortic 390:161–165.
Massei G, Hartley SE. 2000;Disarmed by domestication? Induced responses to browsing in wild and cultivated olive. Oecologia 122:225–231.
Pratt DB, Clark LG. 2004;Amaranthus rudis and A. tuberculatus, one species or two?. J Torrey Bot Soc 128:282–296.
Qu ZZ, Wang YH. 1993. Chinese fruit trees record Chinese jujube The Forestry Publishing House of China. Beijing, China: p. 33–37.
Rosenthal JP, Dirzo R. 1997;Effects life history, domestication and agronomic selection on plant defence against insects: evidence for maize and wild relative. Evol Ecol 11:337–355.
Small E. 1996;Adaption to herbivory in alfalfa (Medicago sativa). Can J Bot 74:807–822.
Smith JSC, Smith OS. 1992;Fingerprinting crop varieties. Adv Agron 47:85–140.
Sneath PHA, Sokal RR. 1973. Numerical taxonomy W.H. Freeman and Company. San Francisco, California, USA: p. 230–234.
Sneath PHA. 1995;Thirty years of numerical taxonomy. Syst Biol 44:281–298.
Von Maydell HJ. 1986. Trees and shrubs of the sahel: Their characteristics and uses GT2. Eschborn, Germany: p. 525.

Article information Continued

Fig. 1

Morphological variability of fruits in various jujube cultivars.

Fig. 2

Scattered diagram of 25 jujube cultivars based on the principal component 1 and 2 variables for 15 morphological characteristics. Major cultivated jujube cultivars in Korea were grouped with two Chinese cultivars in the red circle. 2 Chinese jujube cultivars in the green circle were commonly known as apple jujube. The blue circle, related species Sour jujube was completely separated from cultivated jujube cultivars.

Fig. 3

Dendrogram for cluster analysis of 25 jujube cultivars based on quantitative morphological data.

Table 1

Cultivars name and their source used in this study.

No. Common name Source Codez) No. Common name Source Code
1 Bokjo Korea KV1 14 Jinsixiaozao China C14
2 Mudeung Korea K2 15 Zhongyangmuzao China C15
3 Wolchul Korea K3 16 Sandonglizao China C16
4 Geumseong Korea K4 17 Xiaolizao China C17
5 Boeundaechu Korea KV5 18 Dongzao China C18
6 Dalizao China C6 19 Jinsi No. 3 China C19
7 Huizao China C7 20 Jinsi No. 4 China C20
8 Pozao China C8 21 Yuanling No. 1 China C21
9 Panzao China C9 22 Yuanling No. 2 China C22
10 Zanhuangdazao China C10 23 Chuncheon 7 Korea KV23
11 Dabailing China C11 24 Sour jujube 1 China RS24
12 Damaya China C12 25 Sour jujube 2 China RS25
13 Daguazao China C13
z)

Cultivar codes are abbreviations for the sample characteristics.

K: Korean cultivar, C: Chinese cultivar, KV: Korean native variety, RS: Related species.

Table 2

List of 10 qualitative characteristics of jujube cultivars for phenetic analysis in this study.

No. Trait Abbreviation Unit
1 Growth Bud burst time BBT Code (3-early; 5-mid; 7-late)
2 Flowering time FLT Code (3-early; 5-mid; 7-late)
3 Fructification time FRT Code (3-early; 5-mid; 7-late)
4 Spikes form SF Code (1-present; 2-absent)
5 Leaf Leaf color (upper side) LCU RHS Color Chart group and codez)
6 Leaf color (lower side) LCL RHS Color Chart group and code
7 Leaf shape LS Code (3-elliptical; 5-ovalness; 7-oblong)
8 Serra shape SS Code (1-entire; 3-serrate; 5-biserrate)
9 Fruit Fruit shape FS Code (1-round; 2-round oblate; 3-ovalness; 4-oblong; 5-elliptical)
10 Stone Stone shape STS Code (3-round; 5-ovate; 7-fusiform)
z)

Royal Horticultural Society Color Chart group and code.

Table 3

List of 15 quantitative characteristics of jujube cultivars for phenetic analysis in this study.

No. Trait Abbreviation Unit
1 Leaf Leaf length LL mm
2 Leaf width LW mm
3 Petiole length PL mm
4 Leaf area LA cm2
5 Terminal leaf length TLL mm
6 Terminal leaf width TLW mm
7 Terminal petiole length TPL mm
8 Terminal leaf area TLA cm2
9 Fruit Fruit length FL mm
10 Fruit width FWI mm
11 Flesh index of fruitz) FIF g
12 Fruit weight FWE g
13 Seed Stone length SL mm
14 Stone width SWI mm
15 Stone weight SWE g
z)

Flesh index of fruit was estimated by subtracting stone weight from fruit weight.

Table 4

Representative characteristics of 25 jujube cultivars in the related qualitative traits.

Cultivar
code
Traitz)

BBT FLT FRT SF LCU LCL LS SS FS STS
KV1 5 5 7 0 Green 137Ay) Green 138A 3 2 4 7
K2 5 5 7 0 Green 139A Green 147B 5 2 4 7
K3 5 5 7 0 Green 137A Green 147B 5 2 4 7
K4 5 5 7 0 Green 137B Green 147B 5 2 4 7
KV5 5 5 5 0 Green 137A Green 147B 5 2 3 5
C6 7 7 7 0 Green 137A Green 147B 7 2 3 5
C7 5 5 5 1 Green 139B Green 137C 7 2 4 7
C8 5 5 3 0 Green 137A Green 147B 3 2 3 7
C9 5 5 5 1 Green 137A Green 138A 3 2 4 7
C10 3 3 5 0 Green 137A Green 147B 5 2 4 5
C11 3 5 5 0 Green 139B Green 138A 5 2 5 5
C12 5 5 5 0 Green 137A Green 147B 5 2 2 7
C13 5 5 3 0 Green 137A Green 147B 3 2 5 5
C14 5 5 5 1 Green 137A Green 147B 3 2 3 7
C15 3 3 5 0 Green 137A Green 138A 3 2 3 7
C16 7 7 7 1 Green 137A Green 147B 3 2 3 7
C17 5 7 7 1 Green 137A Green 147B 3 2 4 7
C18 5 7 7 0 Green 137A Green 147B 3 2 5 7
C19 5 5 5 0 Green 137B Green 147B 3 2 3 7
C20 5 3 5 1 Green 137A Green 138A 3 2 3 7
C21 5 5 5 0 Green 137A Green 137C 3 2 4 7
C22 7 5 5 0 Green 139B Green 137C 3 2 5 7
KV23 5 3 5 0 Green 137A Green 137C 3 2 4 7
RS24 3 3 3 1 Green 137B Green 147B 3 2 4 7
RS25 3 3 3 1 Green 137B Green 147B 7 2 3 5
z)

For an explanation of variable symbols, see Table 2.

y)

Abbreviation of RHS Color Chart group and code.

Table 5

Mean values of leaf related quantitative characteristics in 25 jujube cultivars.

Cultivar
code
Traitz)

LL LW PL LA TLL TLW TPL TLA
KV1 66.03bcy) 35.18b 7.16b 16.84c 50.40bc 24.72b 4.49cd 10.41b
±6.58 ±5.63 ±1.37 ±2.56 ±5.63 ±3.08 ±0.71 ±2.16
K2 62.16de 30.51d 6.11cde 16.76c 50.57bc 22.79c 5.28a 9.10c
±5.02 ±4.29 ±0.96 ±2.84 ±5.70 ±4.13 ±0.87 ±1.37
K3 66.08bc 35.60b 6.37bcd 18.38b 52.57ab 27.31a 4.52cd 10.87b
±5.89 ±3.52 ±0.48 ±3.25 ±5.44 ±2.63 ±0.48 ±2.14
K4 68.62ab 38.28a 6.88bc 22.42a 53.95a 27.77a 5.01a 12.11a
±7.53 ±3.64 ±1.05 ±3.94 ±5.51 ±3.52 ±1.04 ±1.68
KV5 54.68gh 29.61d 5.38ef 12.97fg 38.61hi 20.18fgh 3.52hijk 7.00fgh
±4.85 ±3.06 ±1.72 ±1.83 ±5.30 ±2.52 ±1.24 ±1.41
C6 56.98fgh 23.68jk 8.57a 10.33jk 33.77l 14.20k 3.19kl 5.12jkl
±6.88 ±2.96 ±1.39 ±1.71 ±6.13 ±1.95 ±0.71 ±0.33
C7 50.63ij 22.25k 5.72def 9.12l 33.96kl 14.01k 4.23def 4.69l
±4.95 ±1.13 ±0.54 ±1.02 ±2.52 ±2.26 ±0.35 ±0.62
C8 57.52fg 28.70def 5.44def 11.93ghi 44.93de 21.14def 4.26de 6.65ghi
±2.16 ±2.16 ±0.65 ±0.95 ±4.13 ±0.87 ±0.66 ±0.55
C9 63.79cd 33.22c 5.74def 15.56d 49.69c 22.32cd 3.77ghij 7.69e
±4.08 ±3.04 ±1.87 ±1.66 ±3.87 ±2.98 ±0.62 ±1.32
C10 65.19c 34.28bc 4.98f 16.61c 42.75efg 25.75b 3.42jkl 8.27d
±5.45 ±3.02 ±1.15 ±3.07 ±4.10 ±2.08 ±0.52 ±0.92
C11 59.68ef 30.14d 6.69bc 12.29gh 41.63fg 19.04h 4.40cde 6.17i
±5.24 ±1.79 ±0.70 ±1.48 ±1.79 ±1.09 ±0.31 ±0.41
C12 70.29a 25.90ghj 8.26a 14.65de 46.30d 15.60j 4.71bc 5.00jkl
±3.23 ±2.78 ±1.12 ±1.48 ±3.40 ±0.70 ±0.77 ±0.54
C13 57.20fgh 26.82gh 6.77bc 14.08e 35.40jkl 15.99ij 3.53hijk 5.29jkl
±2.93 ±1.43 ±1.08 ±1.63 ±3.73 ±1.56 ±0.34 ±0.60
C14 53.96h 29.25d 5.30ef 11.29hij 40.45gh 21.61cde 4.07efg 4.82kl
±7.11 ±3.17 ±1.39 ±1.86 ±4.15 ±3.16 ±0.86 ±0.82
C15 56.04gh 24.52ij 6.09cde 11.40hij 42.62efg 17.023i 3.73ghij 6.22i
±5.86 ±1.44 ±1.19 ±1.40 ±5.15 ±1.653 ±0.71 ±0.45
C16 47.95ijk 24.48ij 3.05i 12.41gh 42.03fg 20.18fgh 2.19m 7.05fgh
±7.18 ±4.10 ±0.52 ±2.93 ±3.35 ±3.51 ±0.30 ±1.52
C17 54.14h 28.97de 3.85hi 10.72j 43.67ef 22.55c 3.22kl 7.20efg
±7.86 ±4.41 ±0.75 ±1.43 ±5.86 ±3.43 ±0.41 ±1.25
C18 46.49k 22.78jk 3.84hi 12.77g 36.48ijk 15.72ij 3.13l 6.57hi
±9.00 ±5.22 ±0.70 ±1.87 ±5.90 ±2.91 ±0.65 ±0.83
C19 69.30a 32.73c 6.84bc 19.02b 52.13abc 20.62efg 4.60cd 8.35d
±4.51 ±1.65 ±0.73 ±1.30 ±4.24 ±1.48 ±0.63 ±1.07
C20 47.75jk 23.81jk 3.98gh 8.52l 38.18hi 16.84ij 3.12l 5.45jk
±4.66 ±2.12 ±0.23 ±0.79 ±2.80 ±1.82 ±0.20 ±0.30
C21 49.82ij 29.20d 4.81fg 10.73j 36.19jkl 19.65gh 3.84ghi 5.32jkl
±4.81 ±2.14 ±0.67 ±1.23 ±1.52 ±1.31 ±0.61 ±0.75
C22 51.01i 27.44efg 4.92f 11.13hij 40.35gh 20.21fgh 3.48ijk 5.52j
±3.46 ±1.73 ±0.27 ±1.11 ±4.77 ±1.01 ±0.62 ±0.76
KV23 55.69gh 27.10fgh 4.94f 13.88ef 40.40gh 20.32efgh 3.88fgh 7.48ef
±7.87 ±4.84 ±1.31 ±2.88 ±9.28 ±1.73 ±0.97 ±1.46
RS24 56.38gh 25.59hi 4.90f 9.54kl 37.28ij 16.48ij 3.82ghi 4.95jkl
±2.62 ±1.58 ±0.82 ±0.99 ±4.40 ±1.74 ±0.42 ±0.77
RS25 37.06l 18.88l 3.96gh 5.70m 26.51m 12.48l 2.24m 2.97m
±3.77 ±2.21 ±1.09 ±1.20 ±3.74 ±0.79 ±0.50 ±0.69
Meanx) 57.87 28.89 5.73 13.64 42.91 20.24 3.89 7.06
±9.18 ±5.40 ±2.13 ±3.95 ±7.70 ±4.51 ±0.97 ±2.29
z)

For an explanation of variable symbols, see Table 3.

y)

Mean separation within columns by Duncan’s multiple range test at the 0.05 probability level.

x)

The Mean value of 23 Z. jujuba Mill. without two Z. acidojujuba (RS24 and RS25).

Table 6

Mean values of fruit and seed related quantitative characteristics in 25 jujube cultivars.

Cultivar
code
Traitz)

FL FWI FIF FWE SL SWI SWE
KV1 37.28cdey) 27.11de 12.11ef 12.59fg 21.66cde 7.49ghij 0.48k
±2.41 ±2.27 ±2.79 ±2.81 ±1.46 ±0.76 ±0.09
K2 37.71bcd 26.68de 11.22fg 11.84gh 23.86a 8.59de 0.62efg
±2.46 ±2.44 ±2.15 ±2.15 ±2.39 ±0.59 ±0.06
K3 35.31gh 26.35ef 10.56fghi 11.11ghi 22.13bcde 7.63ghijk 0.56ghij
±4.04 ±2.17 ±2.50 ±2.49 ±2.17 ±0.79 ±0.10
K4 37.84bc 26.58de 11.82ef 12.37fg 22.66bc 7.61ghijk 0.55hij
±3.61 ±2.42 ±3.05 ±3.02 ±2.16 ±0.69 ±0.11
KV5 31.00j 25.34fg 9.95ghi 10.52hij 19.17hi 8.58de 0.57fghi
±2.95 ±2.55 ±3.42 ±3.42 ±1.43 ±0.59 ±0.12
C6 35.63fgh 30.77c 14.56d 15.28d 22.07bcde 9.30c 0.71d
±4.21 ±2.22 ±2.89 ±2.87 ±2.89 ±0.77 ±0.12
C7 29.77jk 20.78j 5.82k 6.28k 19.46hi 7.25k 0.46k
±2.87 ±1.59 ±1.66 ±1.66 ±1.45 ±0.34 ±0.02
C8 35.12gh 26.32ef 9.41hij 9.88ij 19.01i 7.17k 0.46k
±2.62 ±1.62 ±1.75 ±1.82 ±2.15 ±0.705 ±0.07
C9 36.27efg 27.21de 11.09fg 11.64gh 21.23ef 7.85ghij 0.55hij
±2.53 ±3.83 ±3.03 ±3.07 ±2.01 ±0.94 ±0.13
C10 33.43i 27.82d 10.99fgh 11.53gh 19.83ghi 7.88ghi 0.55hij
±1.65 ±1.57 ±1.78 ±1.77 ±0.85 ±0.59 ±0.07
C11 38.80b 37.17a 22.02b 23.21b 22.46bcd 11.06b 1.19a
±3.90 ±3.66 ±6.79 ±6.85 ±1.94 ±1.57 ±0.28
C12 34.45hi 25.00g 8.32j 8.94j 22.54bcd 8.32ef 0.62efg
±2.19 ±1.38 ±1.45 ±1.49 ±1.14 ±0.38 ±0.05
C13 40.52a 37.16a 26.85a 27.87a 21.61de 10.70b 1.02c
±2.73 ±3.86 ±6.83 ±6.84 ±1.85 ±1.41 ±0.23
C14 35.22gh 27.06de 11.91ef 12.41fg 19.97ghi 7.51hijk 0.50jk
±1.94 ±1.74 ±1.92 ±1.93 ±0.95 ±0.41 ±0.05
C15 35.34gh 23.61h 10.69fghi 11.30ghi 22.70bcde 8.58de 0.63ef
±2.08 ±2.26 ±0.54 ±0.49 ±0.99 ±0.81 ±0.15
C16 36.16efg 27.48de 13.08de 13.75ef 20.61fg 9.03cd 0.67de
±2.29 ±2.51 ±3.23 ±3.35 ±3.00 ±1.28 ±0.21
C17 33.52i 24.79g 9.98ghi 10.49hij 20.09gh 7.51hijk 0.51ijk
±2.25 ±2.14 ±2.22 ±2.24 ±1.24 ±0.62 ±0.07
C18 35.86efgh 32.91b 16.41c 17.50c 22.18bcde 13.08a 1.09b
±2.95 ±2.52 ±3.12 ±3.13 ±1.12 ±0.39 ±0.14
C19 28.134 21.95i 6.60k 7.10k 16.50j 7.40jk 0.50jk
±2.60 ±1.96 ±1.74 ±1.74 ±2.09 ±0.23 ±0.07
C20 28.54kl 21.98i 6.83k 7.12k 16.87j 6.368 0.290
±1.59 ±1.24 ±0.87 ±0.87 ±0.79 ±0.16 ±0.02
C21 36.16efg 24.21gh 9.16ij 9.72ij 21.23ef 7.92fgh 0.56ghij
±1.99 ±0.55 ±1.32 ±1.30 ±1.99 ±0.32 ±0.08
C22 34.55hi 31.17c 14.09d 14.71de 20.09gh 8.68de 0.62efg
±2.35 ±1.10 ±2.11 ±2.08 ±1.52 ±0.24 ±0.10
KV23 37.09cdef 25.31fg 11.28fg 11.83gh 24.58a 7.43ijk 0.55ghij
±2.67 ±0.48 ±1.26 ±1.26 ±1.31 ±0.64 ±0.06
RS24 26.33m 20.36j 4.239 4.826 19.45hi 8.67de 0.59fgh
±1.35 ±0.23 ±0.41 ±0.43 ±1.14 ±0.66 ±0.04
RS25 13.37n 11.83k 0.63m 1.07m 9.39k 8.01fg 0.44k
±0.78 ±0.82 ±0.16 ±0.19 ±1.06 ±1.28 ±0.10
Meanx) 34.93 27.09 11.89 12.50 20.96 8.33 0.61
±4.05 ±4.68 ±5.43 ±5.59 ±2.63 ±1.55 ±0.23
z)

For an explanation of variable symbols, see Table 3.

y)

Mean separation within columns by Duncan’s multiple range test at the 0.05 probability level.

x)

The Mean value of 23 Z. jujuba Mill. without two Z. acidojujuba (RS24 and RS25).

Table 7

Principal component analysis based on 15 quantitative characteristics for 25 jujube cultivars.

Principal Total Eigenvalue Variance % Accumulate %
PC1 5.755 38.367 38.367
PC2 3.936 26.238 64.605
PC3 1.284 8.558 73.163

Table 8

Eigenvectors associated with the eigenvalues obtained from principal component analysis for 15 quantitative characteristics on 25 jujube cultivars.

Characteristics PC1 PC2 PC3
Leaf length 0.079 0.612 0.627
Leaf width 0.054 0.786 0.267
Petiole length 0.127 0.041 0.865
Leaf area 0.161 0.759 0.282
Terminal leaf length −0.006 0.816 0.266
Terminal leaf width 0.007 0.898 −0.091
Terminal leaf petiole length 0.023 0.464 0.621
Terminal leaf area 0.053 0.845 0.038
Fruit length 0.732z) 0.460 0.018
Fruit width 0.903 0.189 0.038
Flesh index of fruit 0.933 0.087 −0.023
Fruit weight 0.940 0.077 −0.017
Stone length 0.572 0.357 0.183
Stone width 0.716 −0.334 0.120
Stone weight 0.794 −0.206 0.149
z)

Values in bold indicate the most relevant characters (> 0.4) that contributed most to the variation of the particular component.