Genetic Similarity among Varieties of Armeniaca vulgaris Shushanggan in Ili

Shuying CHEN, Guizhi CONG, Jin WANG, Jun LIU, You SHI, Deming QIN, Abudu·Salamu

Forestry Academy of Ili Kazak Autonomous Prefecture, Ili 835000, China

Abstract [Objectives] To analyze the genetic similarity among varieties of Armeniaca vulgaris Shushanggan in Ili. [Methods] The genetic distance among 13 A. vulgaris Shushanggan varieties was compared at the DNA molecular level, and clustering analysis was performed on them. [Results] The 13 varieties of A. vulgaris Shushanggan were classified into four clusters. The first cluster included Shushang Ganxing 1, Shushang Ganxing 4, Gongliu Yexing and Zhenzhu Youxing, and the similarity coefficient between Shushang Ganxing 1 and Shushang Ganxing 4 reached 0.808; the second cluster were Shushang Ganxing 2, Shushang Ganxing 3 and Liguangxing, and the similarity coefficient between Shushang Ganxing 2 and Shushang Ganxing 3 was 0.846[1]; Ili Baixing, 61 Tuan Guyexing, Chaxian Yexing and Huocheng Yexing were classified into the third cluster, and the similarity coefficient between Ili Baixing and 61 Tuan Guyexing was 0.692; and the fourth cluster included Shushang Ganxing W1 and Yixian Yexing, between which the similarity coefficient was 0.692. [Conclusions] This will lay a foundation for the research of variety identification and genetic structure of A. vulgaris Shushanggan.

Key words Armeniaca vulgaris Shushanggan, Variety, Gene similarity, Ili

1 Introduction

Armeniaca

vulgaris

shushanggan(Rosaceae:

Armeniaca

Mill.) is a local variety of Xinjiang apricot, belonging to the Central Asia variety group. It is a small fruit apricot variety, and an excellent local apricot variety in Ili Valley with rich nutrients, good taste, unique flavor and strong adaptability. It can be eaten directly or processed into dried slices. Due to the complex geographical environment and climate in Xinjiang, in different ecological regions, even the same apricot variety has certain differences in growth characteristics and fruit quality. It is difficult to identify a variety singly from phenotypic characteristics. Rapid detection of genetic diversity using molecular marker technology can avoid the influence of environment, tissue specificity and developmental stage. In this study, 18 pairs of SSR primers were designed using SSR (simple sequence repeat) molecular marker technology to study the genetic diversity of apricot materials from different ecological regions and identify apricot varieties in Ili Valley at DNA level through DNA fingerprinting, in order to lay a foundation for research on variety identification and genetic structure of

A

.

vulgaris

shushanggan.

2 Materials and methods

2.1 Materials

A total of 13 varieties of

A

.

vulgaris

shushanggan were selected in this study, including Shushang Ganxing 1 (a bred variety, from Ili Valley, Xinjiang), Shushang Ganxing 2 (a bred variety, from Ili Valley, Xinjiang), Shushang Ganxing 3 (a bred variety, from Ili Valley, Xinjiang), Shushang Ganxing 4 (an excellent variety, from Ili Valley, Xinjiang), Liguangxing (a cultivated variety, from Ili Valley, Xinjiang), Zhenzhu Youxing (a cultivated variety, from Ili, Xinjiang), 61 Tuan Yexing (a wild variety, from the 61Regiment of the Fourth Agricultural Division, Xinjiang Production & Construction Group), Gongliu Yexing (a wild variety, from the shallow area of Mount Tianshan), Huocheng Yexing (a wild variety, from the shallow area of Mount Tianshan), Shushang Ganxing W1 (an excellent variety, from Qiongbole Town, Qapqal Xibe Autonomous County, Ili, Xinjiang), Chaxian Yexing (Qapqal Xibe Autonomous County, Ili, Xinjiang), Ili Baixing (a local variety, from Ili, Xinjiang) and Yixian Yexing (a wild variety, from Gilgelang Township, Yining County) (Table 1). The genetic similarity and genetic distance among the

A

.

vulgaris

shushanggan varieties were analyzed.

Table 1 Basic information of 4 kinds of apricot materials from different habitats of Ili Valley, Xinjiang

2.2 Methods

2.2.1

DNA extraction and PCR amplification. Genomic DNA of the apricot materials was extracted using modified CTAB method. The concentration and purity of the DNA extracted were examined. SSR primers with rich polymorphism and good stability were screened out for identification of apricot varieties and analysis of genetic diversity. SSR amplification products were detected by non-denaturant polyacrylamide gel electrophoresis. PCR products were separated with 6% polyacrylamide gel electrophoresis. After fixing, dyeing, developing, photographic fixing, rinsing and air-drying, the bands were scanned or photographed. The specific test methods and steps are the same as those in a previously published paper:

The

fingerprint

structure

and

genetic

relationship

of

Shushanggan

apricot

:

A

preliminary

study

.

2.2.2

Band pattern recording and data analysis. (i) Observation and statistics of bands. After gel dried, DNA polymorphism band pattern was formed. The SSR bands on the film were quantized and recorded in 0, 1 mode. If band was clear, it was marked as "1"; and if no band appeared in the corresponding position, it was marked as "0". Thus, an original matrix of "1" and "0" was generated.

(ii) Data analysis. After transforming SSR bands into 1, 0 data, Dice similarity coefficient matrix was calculated using SIMQUAL program of NTSYS-2.10e software. The UPGMA method in SHAN program was used for cluster analysis, and the dendrogram was generated by Tree Plot module.

3 Results and analysis

3.1 Band identification

Six pairs of SSR primers with good polymorphism were screened out from the 18 pairs of primers. The four apricot materials were distinguished effectively by electrophoretic map and primer ma039a. The specific matching results of fingerprints are shown in Fig.1, and electrophoresis results are shown in Fig.2.

Note: "1" and "0" indicate the presence and absence of band, distinguished by red and yellow colors, respectively; green color indicates that the test material is distinguished in the row; and blankness indicates that is has been distinguished.

Fig.2 SSR electrophoretograms of the 13 varieties of Armeniaca vulgaris Shushanggan

3.2 Genetic similarity

The results of fingerprint identification show that the 13 varieties of

A

.

vulgaris

shushanggan were clustered into four groups. The genetic distance among different

A

.

vulgaris

shushanggan varieties is shown in Fig.3. The cluste-ring results are shown in Fig.4.

Fig.3 Genetic distance among the 13 varieties of Armeniaca vulgaris Shushanggan

Fig.4 Dendrogram of the 13 varieties of Armeniaca vulgaris Shushanggan

Shushang Ganxing 1, Shushang Ganxing 4, Gongliu Yexing and Zhenzhu Youxing were clustered into one group. Among them, the genetic similarity coefficient between Shushang Ganxing 1 and Shushang Ganxing 4 was 0.808, indicating a relatively close relationship; the average similarity coefficient between Gongliu Yexing and Shushang Ganxing 1, Shushang Ganxing 4 was 0.711; and the average similarity coefficient between Zhenzhu Youxing and Shushang Ganxing 1, Shushang Ganxing 4, Gongliu Yexing was 0.692. The genetic distance between Shushang Ganxing 1 and Shushang Ganxing 4 was closer, smaller than those with Gongliu Yexing and Zhenzhu Youxing.

Shushang Ganxing 1, Shushang Ganxing 3 and Liguangxing were classified into one group. Among them, the genetic similarity coefficient between Shushang Ganxing 2 and Shushang Ganxing 3 was 0.846, the closest. The average similarity coefficient between Liguangxing and Shushang Ganxing 2, Shushang Ganxing 3 was 0.654. In this group, the distance between Shushang Ganxing 2 and Shushang Ganxing 3 was closer, smaller than that with Liguangxing.

Ili Baixing, Huocheng Yexing, 61 Tuan Guyexing and Chaxian Yexing were clustered into one group. The genetic similarity coefficient between Ili Baixing and 61 Tuan Guyexing was 0.692. The average similarity coefficient between Chaxian Yexing and 61 Tuan Guyexing, Ili Baixing was 0.665, and that between Huocheng Yexing and 61 Tuan Guyexing, Ili Baixing, Chaxian Yexing was 0.602. In this group, the genetic distance between Ili Baixing and 61 Tuan Guyexing was the closest, smaller than those with Chaxian Yexing and Huocheng Yexing.

Shushang Ganxing W1 and Yixian Yexing were classified into one group, and their genetic similarity coefficient was 0.692.

4 Discussion

The 13

A

.

vulgaris

Shushanggan varieties were identified by fingerprint and cluster analysis. The varieties clustered into one group have similar genetic background and close genetic relationship. Among the 5 shushang ganxing varieties, the genetic distance between Shushang Ganxing 1 and Shushang Ganxing 4, Shushang Ganxing 2 and Shushang Ganxing 3 was closer, with similarity coefficients greater than 0.808. The ecological performance of Shushang Ganxing W1 was late maturity, and its genetic similarity coefficients with the other four shushing ganxing varieties were in the range of 0.308-0.385, varying greatly, so it can be judged as a new variety type. Among the five wild apricot varieties, the genetic distance between Gongliu Yexing and shushang ganxing varieties was closer, with genetic similarity coefficient ranging from 0.654 to 0.731. Yixian Yexing showed a close genetic distance with Shushang Ganxing W1 with great difference in habitat, and their similarity coefficient was 0.692. The genetic similarity coefficients between 61 Tuan Guyexing, Huocheng Yexing, Chaxian Yexing and shushang ganxing varieties were in the ranges of 0.500-0.692, 0.385-0.577 and 0.346-0.423, respectively.

For the three cultivated apricot varieties, their similarity coefficients with shushang ganxing varieties were in the ranges of 0.615-0.731 (Zhenzhu Youxing), 0.577-0.731 (Liguangxing) and 0.423-0.577 (Ili Baixing), respectively.

The fingerprint of

A

.

vulgaris

Shushanggan varieties constructed by SSR markers and the analysis results of their genetic relationships can be used to help identify apricot varieties. They also provide a reliable method for heterozygosity identification of apricot varieties.