SSR marker primer for quickly identifying varieties of manglietia insignis and application and method thereof

Abstract

The application discloses a kind of SSR marker primers for quickly identifying variety of Lagerstroemia indica, and application and method thereof.The SSR marker primer is one or more than two of primer S01, primer S11 and primer S21;10 kinds of Lagerstroemia indica varieties can be specifically identified, molecular marker resolution is high, and it can be used alone or in combination.The identification method is simple to operate, and is conducive to popularization and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of plant variety identification, and particularly to a SSR marker primer for rapidly identifying Lagerstroemia indica varieties, and an application and method thereof. BACKGROUND

[0002] Lagerstroemia indica, also known as Baibinghong and Yiyushu, is a deciduous shrub or small tree of the Lythraceae family. It has high ornamental value due to its beautiful meaning, long-lasting flowering period, rich flower colors, and elegant tree shape. It is an important woody flowering plant in summer.

[0003] China is the world distribution center and origin center of Lagerstroemia plants (Egolf & Andrick, 1978). According to the records in the Flora of China, new species of Lagerstroemia published in recent years, and other records, there are currently 24 species of Lagerstroemia in China, accounting for about 44% of the total number of species in the world. The earliest record of Lagerstroemia cultivation in China dates back to the Eastern Jin Dynasty, with Wang Jia's Shiyi Ji, which is over 1600 years old. After hundreds of years of cultivation and selection, many new varieties have emerged. Foreign countries have conducted extensive research on Lagerstroemia breeding using Lagerstroemia resources introduced from China in the mid-18th century. The number of Lagerstroemia varieties cultivated by gardeners around the world exceeds 100. It can be seen that whether domestically or internationally, Lagerstroemia is an important woody flowering plant in summer landscaping and plays an important role in the landscaping market.

[0004] In recent years, in order to promote the breeding process of Lagerstroemia, Chinese researchers have conducted extensive resource collection, introduced and preserved a large number of Lagerstroemia resources from domestic and foreign countries, and created a large number of Lagerstroemia varieties. With the extensive collection and continuous accumulation and exchange of Lagerstroemia resources, a large number of homonyms and synonyms have appeared, which has brought great inconvenience and confusion to resource preservation, evaluation, innovation, and research. With the increasing number of Lagerstroemia varieties, the differences between varieties are gradually narrowing, making it difficult to accurately identify them based on morphological characteristics, and this method is easily affected by environmental and seasonal factors. In addition, Lagerstroemia intraspecific hybridization is very common, and interspecific hybridization with Lagerstroemia indica var. fujianensis is also common. Due to environmental and cultivation techniques, morphological differences and variations between individuals within Lagerstroemia are widespread in nature. Therefore, it is of great significance to establish a fast, efficient, and accurate variety identification technology for the sustainable use of Lagerstroemia resources and variety breeding.

[0005] With the development of molecular biology technology, DNA molecular marker technology is also applied to the genetic diversity research and relationship construction of Lagerstroemia indica. Researchers use RAPD, AFLP and ISSR molecular marker technology to conduct genetic analysis on Lagerstroemia indica variety resources; Pooler uses AFLP and RAPD marker technology to analyze the genetic diversity of Lagerstroemia indica (L. fauriei) and L. indica x L. fauriei hybrid variety 'Natchez' (Margaret R. Pooler, Molecular genetic diversity among 12 clones of Lagerstroemia fauriei revealed by AFLP and RAPD markers, HortScience, 38(2), 256-259).

[0006] SSR marker is also called microsatellite DNA. Compared with other molecular markers, SSR marker is inherited in Mendelian manner and is co-dominant; has many alleles, large information amount and high polymorphism; and has the advantages of good repeatability, high stability, good genome coverage and simple operation (Powell et al, The comparison of RFLP, RAPD, AFLP and SSR (microsatellite) markers for germplasm analysis, 1996, Molecular Breeding, 2:225-238), and is widely used in germplasm identification, genetic diversity and genetic structure analysis and genetic map construction. At present, there are few studies on Lagerstroemia indica varieties using SSR molecular marker technology, and there are few reports on identification of Lagerstroemia indica varieties. Moreover, there are many Lagerstroemia indica varieties, and the existing molecular markers have low resolution and are insufficient to identify and distinguish the existing Lagerstroemia indica varieties. Therefore, it is necessary to study and expand the marker primers and suitable identification methods for identifying Lagerstroemia indica varieties. SUMMARY

[0007] The purpose of the present application is to provide a SSR marker primer for quickly identifying Lagerstroemia indica varieties, its application and method, which can accurately identify early in the seedling stage without waiting for a long growth period, and can quickly and accurately identify Lagerstroemia indica varieties.

[0008] The application of a SSR marker primer for quickly identifying Lagerstroemia indica varieties in identifying Lagerstroemia indica varieties, wherein the SSR marker primer is one or two or more of primer S01, primer S11 and primer S21.

[0009] The primer S01 is as follows:

[0010] Upstream primer: 5'-TGAAGTCCTCCACGAAAAGCT-3' (SEQ ID NO: 1),

[0011] Downstream primer: 5'-ACTGCATCTCAACGGAAGCA-3' (SEQ ID NO: 2);

[0012] The primer S11:

[0013] Upstream primer: 5'-TCGGATTTAGCCATGCTTGGA-3' (SEQ ID NO: 3),

[0014] Downstream primer: 5'-CTCCAGCAGGATCTTAGGCG-3' (SEQ ID NO: 4);

[0015] The primer S21:

[0016] Upstream primer: 5'-ACATGGCTCCCATCACACAG-3' (SEQ ID NO: 5),

[0017] Downstream primer: 5'-CAGGGGATTCTTGTTTTGCTTT-3' (SEQ ID NO: 6).

[0018] Optionally, a fluorescent dye, a fluorescent probe or other material for fluorescent labeling can be introduced into the primer to design a fluorescently labeled primer to adapt to various fluorescent detection equipment or fluorescent reading equipment. Generally, the upstream primer in the primer is fluorescently labeled, for example, the upstream of the primer is modified with FAM (blue) or HEX (green) biological fluorescent gene.

[0019] The Lagerstroemia indica variety is one of Acoma (L. indica 'Acoma'), Biloxi (L. indica 'Biloxi'), Catawba (L. indica 'Catawba'), Petit Red (L. indica 'Petit Red'), Red Rocket (L. indica 'Red Rocket'), Ewei 1 (L. indica 'Ewei 1'), Yanzhihong (L. indica 'Yanzhihong'), Fenjin (L. indica 'Fenjin'), Qinz (L. indica 'Qinz'), Ziqi (L. indica 'Ziqi') or two or more of them.

[0020] A method for rapidly identifying Lagerstroemia indica varieties, comprising the steps of:

[0021] (1) extracting DNA from fresh leaves of each Lagerstroemia indica variety sample to be tested;

[0022] (2) using the DNA extracted in step (1) as a DNA template, performing PCR amplification with the SSR marker primer according to claim 1 or 2 to obtain the PCR amplification product of each primer;

[0023] (3) detecting the PCR amplification product of each primer in step (2) by capillary electrophoresis to obtain the PCR amplification product band of each sample to be tested, and determining the variety of each sample to be tested according to the PCR amplification product band of each sample to be tested.

[0024] Optionally, the determination criterion for determining the variety of each sample to be tested according to the PCR amplification product band of each sample to be tested is that if the amplified fragment size is the same, it is determined as the same variety; otherwise, it is determined as different varieties.

[0025] Optionally, the SSR marker primer is primer S01, and in step (3), the determination criterion for determining the variety of each sample to be tested according to the PCR amplification product band of each sample to be tested is that:

[0026] the PCR amplification product band has two bands and the length is 153bp and 171bp, which is Acoma;

[0027] the PCR amplification product band has two bands and the length is 159bp and 162bp, which is Biloxi;

[0028] the PCR amplification product band has two bands and the length is 159bp and 171bp, which is Catawba;

[0029] the PCR amplification product band has two bands and the length is 161bp and 173bp, which is Petit Red;

[0030] the PCR amplification product band has two bands and the length is 171bp and 173bp, which is Honghuojian;

[0031] the PCR amplification product band has two bands and the length is 157bp and 161bp, which is Ewei No.1;

[0032] the PCR amplification product band has one band and the length is 159bp, which is Anzhihong;

[0033] the PCR amplification product band has two bands and the length is 157bp and 169bp, which is Fenjin;

[0034] the PCR amplification product band has two bands and the length is 157bp and 159bp, which is Qinzi;

[0035] the PCR amplification product band has one band and the length is 161bp, which is Ziqi.

[0036] Optionally, the SSR marker primer is primer S11, and the determination criterion for determining the variety of Lagerstroemia indica to which each sample belongs in step (3) is that the number of bands of the PCR amplification product of each sample is determined.

[0037] Acoma is Lagerstroemia indica with two bands of PCR amplification product with lengths of 333bp and 342bp;

[0038] Biloxi is Lagerstroemia indica with one band of PCR amplification product with a length of 318bp;

[0039] Catawba is Lagerstroemia indica with two bands of PCR amplification product with lengths of 318bp and 353bp;

[0040] Petit Red is Lagerstroemia indica with one band of PCR amplification product with a length of 329bp;

[0041] Red Rocket is Lagerstroemia indica with two bands of PCR amplification product with lengths of 329bp and 347bp;

[0042] Ewei No. 1 is Lagerstroemia indica with two bands of PCR amplification product with lengths of 340bp and 377bp;

[0043] Crimson is Lagerstroemia indica with two bands of PCR amplification product with lengths of 340bp and 354bp;

[0044] Pink Gold is Lagerstroemia indica with one band of PCR amplification product with a length of 358bp;

[0045] Qinzi is Lagerstroemia indica with two bands of PCR amplification product with lengths of 354bp and 374bp;

[0046] Ziqi is Lagerstroemia indica with two bands of PCR amplification product with lengths of 345bp and 353bp.

[0047] Optionally, the SSR marker primer is primer S21, and the determination criterion for determining the variety of Lagerstroemia indica to which each sample belongs in step (3) is that the number of bands of the PCR amplification product of each sample is determined.

[0048] Acoma is Lagerstroemia indica with one band of PCR amplification product with a length of 154bp;

[0049] Biloxi is Lagerstroemia indica with one band of PCR amplification product with a length of 158bp;

[0050] Catawba is Lagerstroemia indica with two bands of PCR amplification product with lengths of 153bp and 186bp;

[0051] Petit Red is Lagerstroemia indica with two bands of PCR amplification product with lengths of 154bp and 182bp;

[0052] The PCR amplification product bands with two bands and the length of 154 bp and 158 bp are Hongluoche;

[0053] The PCR amplification product bands with two bands and the length of 154 bp and 188 bp are Ewei No.1;

[0054] The PCR amplification product bands with two bands and the length of 156 bp and 188 bp are Hongxi Hong;

[0055] The PCR amplification product band with one band and the length of 182 bp is Fenjin;

[0056] The PCR amplification product bands with two bands and the length of 153 bp and 188 bp are Qinzi;

[0057] The PCR amplification product bands with two bands and the length of 150 bp and 182 bp are Ziqi.

[0058] Optionally, in step (2), the total volume of the PCR amplification reaction system is 15 μL, including 1 μL of 50 ng / μL DNA template, 7.5 μL of 2×PCR mix, 0.3 μL of 10 mmol / L upstream primer, 0.3 μL of 10 mmol / L downstream primer, and 5.9 μL of deionized water.

[0059] Optionally, in step (2), the PCR amplification program is as follows: first, pre-denaturation treatment at 98 ℃ for 3 min, then 35 cycles, each cycle including a denaturation step at 94 ℃ for 20 s, an annealing step at 55-60 ℃ for 20 s, and an extension step at 72 ℃ for 40 s, after all cycles, final extension at 72 ℃ for 5 min.

[0060] Optionally, in step (3), 1 μL of the PCR amplification product is taken before capillary electrophoresis detection, 9 μL of high-loading deionized formamide (HiDi) is added, denaturation is carried out at 95 ℃ for 3 min, and then ice water bath is immediately carried out, and then electrophoresis detection is carried out.

[0061] Optionally, in step (3), the capillary electrophoresis detection is carried out by using an ABI 3730XL sequencer.

[0062] The present application has the beneficial effects:

[0063] The present application adopts three pairs of specific primers to identify and distinguish the existing Lagerstroemia indica varieties, has high molecular marker resolution, can be used alone or in combination, and can quickly and accurately identify the Lagerstroemia indica varieties.

[0064] The application develops 3 pairs of SSR molecular markers from Lagerstroemia indica transcriptome data and related literatures, rapidly identifies Lagerstroemia indica varieties, and provides technical support for Lagerstroemia indica variety identification and molecular marker assisted breeding. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 Capillary electrophoresis diagram of Acoma primer S01 genotype of Lagerstroemia indica variety;

[0066] Figure 2 Capillary electrophoresis diagram of Biloxi primer S01 genotype of Lagerstroemia indica variety;

[0067] Figure 3 Capillary electrophoresis diagram of Catawba primer S01 genotype of Lagerstroemia indica variety;

[0068] Figure 4 Capillary electrophoresis diagram of Petit Red primer S01 genotype of Lagerstroemia indica variety;

[0069] Figure 5 Capillary electrophoresis diagram of red rocket primer S01 genotype of Lagerstroemia indica variety;

[0070] Figure 6 Capillary electrophoresis diagram of Lagerstroemia indica variety Owei No. 1 primer S01 genotype;

[0071] Figure 7 Capillary electrophoresis diagram of Lagerstroemia indica variety Carmine primer S01 genotype;

[0072] Figure 8 Capillary electrophoresis diagram of Lagerstroemia indica variety powder gold primer S01 genotype;

[0073] Figure 9 Capillary electrophoresis diagram of Lagerstroemia indica variety Qinzhi primer S01 genotype;

[0074] Figure 10 Capillary electrophoresis diagram of Lagerstroemia indica variety Ziqi primer S01 genotype;

[0075] Figure 11 Capillary electrophoresis diagram of Acoma primer S11 genotype of Lagerstroemia indica variety;

[0076] Figure 12 Capillary electrophoresis diagram of Biloxi primer S11 genotype of Lagerstroemia indica variety;

[0077] Figure 13 Capillary electrophoresis diagram of Catawba primer S11 genotype of Lagerstroemia indica variety;

[0078] Figure 14 Capillary electrophoresis diagram of Petit Red primer S11 genotype of Lagerstroemia indica variety;

[0079] Figure 15 Capillary electrophoresis diagram of S11 primer genotype of Lagerstroemia indica variety Red Rocket;

[0080] Figure 16 Capillary electrophoresis diagram of S11 primer genotype of Lagerstroemia indica variety Owei No.1;

[0081] Figure 17 Capillary electrophoresis diagram of S11 primer genotype of Lagerstroemia indica variety Carmine;

[0082] Figure 18 Capillary electrophoresis diagram of S11 primer genotype of Lagerstroemia indica variety Powder Gold;

[0083] Figure 19 Capillary electrophoresis diagram of S11 primer genotype of Lagerstroemia indica variety Qinzhi;

[0084] Figure 20 Capillary electrophoresis diagram of S11 primer genotype of Lagerstroemia indica variety Ziqi;

[0085] Figure 21 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Acoma;

[0086] Figure 22 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Biloxi;

[0087] Figure 23 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Catawba;

[0088] Figure 24 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Petit Red;

[0089] Figure 25 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Red Rocket;

[0090] Figure 26 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Owei No.1;

[0091] Figure 27 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Carmine;

[0092] Figure 28 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Powder Gold;

[0093] Figure 29 Capillary electrophoresis diagram of S21 primer genotype of Lagerstroemia indica variety Qinzhi;

[0094] Figure 30The capillary electrophoresis chart of the primer S21 genotype of the Lagerstroemia indica variety Ziqi. DETAILED DESCRIPTION

[0095] The application is further described in detail below in conjunction with the accompanying drawings and examples.

[0096] Example 1

[0097] Research object:

[0098] Five foreign Lagerstroemia indica varieties and five domestic Lagerstroemia indica varieties were used as research objects, the five foreign Lagerstroemia indica varieties included Acoma (L. indica 'Acoma') (marked as B3), Biloxi (L. indica 'Biloxi') (marked as B5), Catawba (L. indica 'Catawba') (marked as B7), Petit Red (L. indica 'Petit Red') (marked as B20), and Red Rocket (L. indica 'Red Rocket') (marked as HHJ), and the five domestic Lagerstroemia indica varieties included Ewei No. 1 (L. indica 'Ewei 1') (marked as EW1), Yanzhihong (L. indica 'Yanzhihong') (marked as YZH), Fenjin (L. indica 'Fenjin') (marked as FJ), Qinz (L. indica 'Qinz') (marked as QZ), and Ziqi (L. indica 'Ziqi') (marked as ZQ).

[0099] Research method:

[0100] (1) Sampling: Fresh and disease-free leaves of Lagerstroemia indica were collected for DNA extraction.

[0101] (2) Lagerstroemia indica DNA extraction method: DNA extraction was performed using a DNA extraction kit.

[0102] (3) Lagerstroemia indica DNA detection method

[0103] The quality of nucleic acid was checked by 1.0% (percentage of the weight of agarose gel to the volume of buffer) agarose gel electrophoresis, and the band should be clear and single, indicating that the DNA sample was qualified. The purity and concentration of DNA were evaluated by a NanoDrop one ultramicro UV spectrophotometer, and an OD260 / OD280 ratio of 1.8-2.0 indicated that the sample was not contaminated. The DNA concentration needed to be ≥20 ng / μL. The qualified DNA was stored at -20℃ for standby, providing preparation for subsequent PCR amplification and other experiments.

[0104] (4) SSR primer development:

[0105] Based on the sequencing assembly of Lagerstroemia indica transcriptome data, 45 pairs of SSR primers were developed independently, and 15 pairs of SSR primers were screened from the literature published in recent years. Among the total of 60 pairs of primers, 19 pairs of SSR primers with polymorphism were screened out.

[0106] (5) 108 Lagerstroemia indica varieties were detected by capillary electrophoresis using the 19 pairs of screened SSR primers. The upstream of the primer was modified with FAM (blue) or HEX (green) biological fluorescence gene.

[0107] (6) The total volume of the fluorescence PCR amplification reaction system was 15 μL, including 1 μL of 50 ng / μL DNA template, 7.5 μL of 2x PCR Mix, 0.3 μL of 10 mmol / L upstream primer, 0.3 μL of 10 mmol / L downstream primer, and 5.9 μL of deionized water (ddH2O).

[0108] (7) The PCR amplification program was set as follows: first, pre-denaturation treatment at 98℃ for 3 min to ensure complete denaturation of the DNA template. Then, 35 cycles were implemented, each cycle including a denaturation step at 94℃ for 20 s, an annealing step at 55-60℃ for 20 s, and an extension step at 72℃ for 40 s. After completing all cycles, a final extension at 72℃ for 5 min was performed to ensure complete extension of all amplified products. Finally, the reaction system was stored at 4℃.

[0109] (8) 1 μL of the above PCR product was taken and added to 9 μL of loading (HiDi), denatured at 95℃ for 3 min, immediately placed in ice water bath, and then subjected to electrophoresis detection on a sequencing instrument ABI 3730XL.

[0110] (9) The electrophoresis detection data were statistically analyzed using GeneMarker software. The software gave the accurate value (bp) of the target SSR fragment by analyzing the difference between the target peak and the internal standard in the same lane. According to the size difference of the fragments, the varieties were identified. If the amplified fragment size was the same, it was determined as the same variety; otherwise, it was determined as different varieties. The same primer was coded with letters according to the size of the fragments from small to large, thereby constituting the genotype of each variety.

[0111] (10) Finally, 3 pairs of primers were selected from 19 pairs of polymorphic SSR primers (see Table 1) to achieve one-district identification for 10 Lagerstroemia varieties as the research object, among which 2 pairs of primers were independently developed and 1 pair of primers was from the literaturea (WANG X, DEAN D, WADLP, et al. Development of Microsatellite Markers from Crape Myrtle (Lagerstroemia L.) [J / OL]. HortScience, 2010, 45(5): 842-844).

[0112] Table 1 SSR primers for Lagerstroemia varieties

[0113]

[0114] The repeat units of each primer have no special influence on the identification of Lagerstroemia varieties.

[0115] Research results:

[0116] For S01 primer, a total of 8 alleles were detected, with sizes of 153 bp, 157 bp, 159 bp, 161 bp, 162 bp, 169 bp, 171 bp, and 173 bp, respectively. The fragments were encoded with letters a to h from small to large to constitute the genotype of each variety. It can be seen that the genotype of each variety is different, indicating that S01 primer can achieve one-district identification for 10 Lagerstroemia varieties.

[0117] For S11 primer, a total of 12 alleles were detected, with sizes of 318 bp, 329 bp, 333 bp, 340 bp, 342 bp, 345 bp, 347 bp, 353 bp, 354 bp, 358 bp, 374 bp, and 377 bp, respectively. The fragments were encoded with letters a to l from small to large to constitute the genotype of each variety. It can be seen that the genotype of each variety is different, indicating that S11 primer can achieve one-district identification for 10 Lagerstroemia varieties.

[0118] For S21 primer, a total of 8 alleles were detected, with sizes of 150 bp, 153 bp, 154 bp, 156 bp, 158 bp, 182 bp, 186 bp, and 188 bp, respectively. The fragments were encoded with letters a to h from small to large to constitute the genotype of each variety. It can be seen that the genotype of each variety is different, indicating that S21 primer can achieve one-district identification for 10 Lagerstroemia varieties.

[0119]

Claims

1. An application of SSR marker primers for rapid identification of crape myrtle varieties in identifying crape myrtle varieties, characterized in that: The SSR marker primer is one or both of primer S01 and primer S11; The primer S01: Upstream primer: 5'-TGAAGTCCTCCACGAAAAGCT-3', Downstream primer: 5′-ACTGCATCTCAACGGAAGCA-3′; The primer S11: Upstream primer: 5'-TCGGATTTAGCCATGCTTGGA-3', Downstream primer: 5′-CTCCAGCAGGATCTTAGGCG-3′; The crape myrtle varieties are two or more of Acoma, Biloxi, Catawba, Petit Red, Red Rocket, Ewei No. 1, Rouge, Pink Gold, Qin Purple, and Ziqi.

2. The use according to claim 1, characterized in that The primer is a fluorescent-labeled primer.

3. A method for quickly identifying crape myrtle varieties, characterized in that: Including steps: (1) Extract DNA from fresh leaves of each sample of the crape myrtle variety to be tested; (2) using each DNA extracted in step (1) as a DNA template, and performing PCR amplification using the SSR marker primers described in claim 1 or 2 to obtain PCR amplification products of each primer; (3) Detecting the PCR amplification products of each primer in step (2) by capillary electrophoresis to obtain PCR amplification product bands of each sample to be tested, and determining the crape myrtle variety to which the sample belongs based on the PCR amplification product bands of each sample to be tested; The crape myrtle varieties are two or more of Acoma, Biloxi, Catawba, Petit Red, Red Rocket, Ewei No. 1, Rouge, Pink Gold, Qin Purple, and Ziqi.

4. The method according to claim 3, characterized in that The criterion for determining the crape myrtle variety to which each sample to be tested belongs based on the PCR amplification product bands is: if the amplified fragments are the same in size, they are determined to be the same variety; otherwise, they are determined to be different varieties.

5. The method according to claim 3 or 4, characterized in that The SSR marker primer is primer S01. In step (3), the criterion for determining the crape myrtle variety to which each sample belongs is determined based on the PCR amplification product bands of each sample to be tested: The PCR amplification product with two bands of 153 bp and 171 bp in length is Acoma; The one with two PCR amplification product bands of 159 bp and 162 bp in length is Biloxi; The PCR amplification product with two bands of 159 bp and 171 bp in length is Catawba; The PCR amplification product with two bands of 161 bp and 173 bp in length is Petit Red; The PCR amplification product with two bands of 171 bp and 173 bp in length is Red Rocket; The one with two PCR amplification product bands of 157 bp and 161 bp in length is Ewei 1; The PCR amplification product with one band and a length of 159 bp is carmine; The PCR amplification product with two bands and lengths of 157 bp and 169 bp is pink gold; The PCR amplification product with two bands of 157 bp and 159 bp in length is Qin Zi; The PCR amplification product had one band with a length of 161bp, which was Ziqi.

6. The method according to claim 3 or 4, characterized in that The SSR marker primer is primer S11. In step (3), the criterion for determining the crape myrtle variety to which each sample belongs is determined based on the PCR amplification product bands of each sample to be tested: The PCR amplification product with two bands of 333 bp and 342 bp in length is Acoma; The PCR amplification product with one band and a length of 318 bp is Biloxi; The one with two PCR amplification product bands of 318 bp and 353 bp in length is Catawba; The PCR amplification product with one band and a length of 329 bp is Petit Red; The PCR amplification product with two bands of 329 bp and 347 bp in length is Red Rocket; The one with two PCR amplification product bands of 340 bp and 377 bp in length is Ewei 1; The PCR amplification product with two bands and lengths of 340 bp and 354 bp is carmine; The PCR amplification product with one band and a length of 358 bp is pink gold; The PCR amplification product with two bands of 354 bp and 374 bp in length is Qin Zi; The PCR amplification product with two bands of 345bp and 353bp in length is Ziqi.

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