CN117106965A - Wheat spike length related molecular marker and application thereof - Google Patents

Abstract

The application discloses a wheat spike length related molecular marker and application thereof. Genotype data is obtained by utilizing a Wheat wheat55K high-throughput gene chip, allelic variation for increasing the spike length is detected on a Wheat 5B chromosome and is derived from a spike length locus QSL.yaas-5B of Yangmai 12, and 1 KASP (kaSP) marking primer group KASP_Q.5B is developed according to the closely linked marking information of the Wheat, so that the spike length is efficiently screened. Experiments prove that the KASP molecular marker KASP_Q.5B can be used for molecular marker assisted selective breeding of wheat spike length. The development and utilization of KASP_Q.5B provide a powerful tool for molecular breeding of wheat yield traits.

Description

Wheat spike length related molecular marker and application thereof

Technical Field

The application belongs to the technical field of molecular breeding, and particularly relates to a wheat ear length related molecular marker and application thereof.

Background

Wheat (Triticum aestivum l.) is one of the major food crops in the world, and in international situations where population is rapidly growing and cultivated area is continuously decreasing, improvement of wheat yield is particularly important. Since wheat ears are important reproductive organs, several studies have shown that spike shape traits are significantly related to yield components (Gao et al, 2015; hu et al, 2020). Therefore, understanding the genetic characteristics of wheat spike length traits is of great value for yield breeding. Wheat ear length is a complex quantitative trait controlled by multiple genes/QTLs such as Q, tasg-D1 and AGO1D (Chen et al 2020; xu et al 2022). QTL localization is an effective way to reveal the genetic basis of these complex quantitative traits. (JI et al, 2021) genotyping the extreme pool using BSE-Seq analysis, initially mapped QSL.cib-5A on the 5A chromosome, contributing 7.88% -26.60% of the phenotypic variation. (Zhou et al, 2017) detected 9 spike length QTLs based on the wheat 90K SNP chip, accounting for 23.60% contribution rate at the highest. (Li et al, 2021) 2 major QTLs controlling spike length and having pleiotropic effects on plant height, thousand grain weight and grain length were identified and validated using a wheat55K SNP chip. Related researches show that the spike length QTL not only shows multi-effect (Li, et al, 2021) on yield-related characters such as thousand grain weight, grain length and the like, but also has certain connection with wheat scab (Liu Chengbin, et al, 2013). Rht1 and Rht2 genes are insensitive to endogenous Gibberellins (GA), producing shorter plants and smaller cells (Keys et al, 1989; rebetzke et al, 2004; botwright et al, 2005), whereas Rht5, rht8, rht22, rht24 and Rht25 are responsive to GA, exhibiting multiple effects on both spike density and spike length, except for reduced plant height (Peng et al, 1999; chen et al, 2014). Therefore, in addition to exploring new major spike length QTLs, it is important to understand their pleiotropic effects on other related traits. Yangmai 12 and Pingzhan 1 are two good wheat varieties released in the middle and downstream of Yangtze river and Huang-Huai river respectively. The spike length of Yangmai 12 is long spike, and the wheat is resistant to scab. Therefore, the cluster of Yangmai 12/elytrigia repens No. RIL (Recombinant inbred lines) can be utilized to excavate the spike length site of Yangmai 12, thereby providing gene resources for high-yield wheat breeding.

The KASP technology is based on specific matching of primer terminal base and typing detection of SNP by universal fluorescent probe, and typing can be completed by combining fluorescent quantitative PCR instrument or common PCR instrument with enzyme label instrument. The KASP technology is similar to TaqMan (fluorescent probe method for detecting oligonucleotides) and is based on reading judgment of terminal fluorescent signals, each well reaction adopts two genotypes of a single SNP locus detected by double-color fluorescence, and different SNPs correspond to different fluorescent signals. However, it does not require that each SNP site synthesizes a specific fluorescent primer, and all site detection can finally be amplified by using a universal fluorescent primer, which reduces the reagent cost of the KASP technology and makes it more practical. After many agronomic traits or disease and stress resistance related genes/loci in modern wheat are excavated or finely positioned, researchers develop KASP markers according to closely linked marker flanking sequences on both sides of the loci, so that the KASP markers are convenient for breeders to use (Su et al, 2018; zhang et al, 2020; hu Wenjing et al, 2022). The KASP technique has the advantages of high throughput, ease of detection, etc. (rashed et al, 2019). SNP linked with target characters obtained by QTL positioning or GWAS analysis can be converted into KASP marker set for breeding. (Raspeed et al, 2019) a set of 70 wheat functional genes KASP markers has been developed and has found widespread use.

Disclosure of Invention

In order to overcome the defects in the prior art, the application provides a linkage molecular marker for molecular marker assisted selection and spike length genotype increasing wheat breeding. Genotype data is obtained by utilizing a wheat55K SNP Wheat high-throughput gene chip, a QTL region QSL.yaas-5B which is derived from Wheat variety Yangmai 12 and is obviously related to the spike length is detected, and a KASP (kali-related sequence) marker primer group is further developed near the peak value of the QTL through screening the effectiveness and reliability of a nearby SNP sequence, so that the Wheat germplasm of the genotype for increasing the spike length is efficiently screened.

One of the purposes of the application is to provide a wheat spike length-related KASP molecular marker, which is located on chromosome 5B in a wheat genome and is shown as SEQ ID NO. 4.

The second object of the present application is to provide a KASP primer set for detecting the molecular marker, wherein the KASP primer set is a set of primers X1 for detecting whether the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID No.4 on chromosome 5B in the wheat genome is CC, TT, C or T, and the set of primers X1 comprises two upstream primers and one downstream primer;

the upstream primer is designed according to 36 th deoxyribonucleotide of a sequence shown as SEQ ID NO.4 on chromosome 5B in the wheat genome and an upstream sequence thereof, wherein the 3 'terminal deoxyribonucleotide of one upstream primer is C, and the 3' terminal deoxyribonucleotide of the other upstream primer is T;

the downstream primer is designed according to the downstream sequence of 36 th deoxyribonucleotide of the sequence shown in SEQ ID NO.4 on chromosome 5B in the wheat genome.

Further, the set of primers X1 consists of an upstream primer shown as SEQ ID NO.1 and SEQ ID NO.2 and a downstream primer shown as SEQ ID NO. 3.

It is a further object of the present application to provide the use of said molecular markers or said KASP primer set in any of the following:

(A) Identifying or assisting in identifying the wheat spike length character;

(B) Predicting or comparing the wheat spike length character to be detected;

(C) Selecting or screening wheat single plants or lines or varieties with wheat spike length characters;

(D) Preparing a product for identifying or assisting in identifying the wheat spike length trait;

(E) Preparing the products of wheat single plants or strains or varieties for breeding or screening the wheat spike length characters.

The fourth object of the present application is to provide any one of the following methods:

method A: a method for comparing the length characteristics of wheat ears to be tested, comprising the following steps (A1) or (A2):

(A1) Detecting whether the 36 th genotype of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the wheat genome is CC or TT or CT;

(A2) The wheat ear length to be tested was determined as follows: the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome is CC, and the wheat to be detected has allelic variation for increasing the spike length;

method B: a method for breeding or screening wheat single plants or strains or varieties with wheat spike length characters comprises the following steps:

(B1) Detecting whether the 36 th genotype of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the wheat genome is CC or TT or CT;

(B2) Selecting wheat to be detected, of which the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome is homozygote of C, as a parent for breeding, and selecting wheat of which the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in each generation of breeding is homozygote of C, so as to finally obtain a wheat single plant or strain or variety with relatively long wheat spike length;

(B3) Selecting the wheat to be detected, of which the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome is a homozygote of T, as a parent for breeding, and selecting the wheat of which the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in each generation of breeding is a homozygote of T, thereby finally obtaining a wheat single plant or strain or variety with relatively short spike length.

Further, the specific operations of the step (A1) or the step (B1) are as follows:

performing PCR amplification on the wheat genome DNA to be detected by using the primer group, performing fluorescent signal scanning on the amplified product, analyzing scanning data, and determining 36 th deoxyribonucleotide type shown by SEQ ID NO.4 on chromosome 5B in the wheat gene to be detected according to the following steps:

if the fluorescence signal data of the amplified product of the wheat to be detected shows red, the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome of the wheat to be detected is a homozygote of C;

if the fluorescence signal data of the amplified product of the wheat to be detected shows blue color, the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome of the wheat to be detected is a homozygote of T.

Compared with the prior art, the application acquires genotype data by utilizing the wheat55 KSNP Wheat high-throughput gene chip, detects a QTL region QSL.yaas-5B which is derived from Wheat variety Yangmai 12 and is obviously related to the Wheat spike length, and further develops 1 KASP mark primer group near the QTL peak value through screening the effectiveness and reliability of a nearby SNP sequence so as to efficiently screen Wheat germplasm of the genotype for increasing the Wheat spike length. The KASP marker provides a good tool for effective utilization of the wheat spike length locus QSL.yaas-5B in high-yield breeding, can rapidly screen the wheat spike length characters, provides convenience for screening wheat materials carrying excellent allelic variation for increasing spike length, and improves the wheat breeding efficiency.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a partial genetic linkage map of chromosome 5B and a schematic representation of QSL.yaas-5B mapping in example 1.

FIG. 2 is a typing result of KASP primer group KASP_Q.5B of QSL.yaas-5B in example 3 in 180 natural populations.

Detailed Description

Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, which should not be construed as limiting the scope of the present application. It is noted that unless otherwise indicated, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. As a professional agricultural research institution, the applicant has long stored relevant germplasm materials, and relevant wheat varieties are all publicly available in the market or in the existing germplasm banks.

Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present application are those conventional in the art. Reagents and materials used in the following examples are commercially available unless otherwise specified.

Example 1 screening for sites of stability significantly correlated with wheat ear length

In this example, 205 parts of recombinant inbred line (F) derived from Yangmai 12 Xelytrigia 1 ₁₀ ) As a material, the recombinant inbred line and 2 parents are planted in the general law test base in Jiangsu river region in 2019, 2020 and 2021 in 3 growing seasons, are planted in the general law test base in 2019 and 2021 in 2 growing seasons, and are planted in the general law of the state of Jingzhou river in 2020 and are planted in the general flood test base in 1 growing season for carrying out ear length agronomic trait investigation. 2 lines are planted in each line in 2 repetitions with 25 grains per line, a line length of 1.5m and a line spacing of 0.30m, and the experimental field management measures are carried out according to a local cultivation mode. The method comprises the steps of randomly selecting 20 representative plants with similar RIL growth states at the later stage of wheat grouting, and measuring the ear length of a main ear in 6 environments, wherein the measuring method comprises the following steps: the miscanthus was not counted from the basal to the tip of the top spike.

Genomic DNA was extracted from fresh leaf tissue by CTAB (Jiang et al 2020), and the DNA integrity and quantity were checked by gel electrophoresis.

The parental and recombinant inbred populations were genotyped using a wheat55K Single Nucleotide Polymorphism (SNP) array containing 53063 SNPs provided by the zhou-jakob-labeled (beijing) biotechnology limited. Then, 12 KASP markers or SSR markers related to known genes such as Vrn-B1, rht-D1, rht8 and the like are selected to genotype the parent and RIL population, and an encrypted genetic map (Raspeed et al, 2016; zhang et al, 2019; xu et al, 2020; zhu et al, 2021) is selected. All polymorphic SNP flanking sequences were aligned to the International wheat genome sequencing Association (IWSSC) Ensembl Plants database (http:// Plants. Ensembl. Org) China spring reference genome v2.1 (Ref v 2.1) to obtain their physical positions and were taken as 1E ^-10 Is set to the desired value of (2)(E) As a significance threshold.

The wheat55K SNP chip result is firstly subjected to preliminary quality control, original genotype data is filtered and de-redundant by using Icimapping v4.1 software (http:// www.isbreeding.net) (SNPs with deletion rate more than 20% and minimum allele frequency less than 5% and bias separation (χ2 is more than or equal to 33.3%) can be deleted simultaneously by using a BIN function, redundant SNPs are deleted), filtered markers are clustered by using a MAP function (Li et al, 2007;2008; meng et al, 2015), and flanking sequences of the markers are placed in an International wheat genome sequencing alliance database v2.1 (International Wheat Genome Sequencing Consortium, IWSSC) to be compared with physical positions (Ma et al, 2021) (WheatOmics 1.0, http:// 202.194.139.32/blast. Html). Genetic distances for each population were calculated using the Kosambi mapping function in JoinMap 4.0 software (Kosambi et al, 1944; van et al, 2006). Spike length QTL detection was performed using the "BIP" function of IciMapping v4.1 with the complete interval mapping (ICIM) algorithm, with the LOD threshold set to 3.0 (Li et al 2021). The genetic map covering QTL regions was mapped using maphart v2.32 (Voorrips, 2002). QTLs that lie within overlapping confidence intervals are considered identical. The physical position of the QTL flanking markers was compared with previously reported genes/QTLs (http:// 202.194.139.32/blast. Html and http:// writes. Sdau. Edu. Cn/genes /).

The stable spike length locus QSL.yaas-5B in 4 different environments and Mean values is detected in the Yangmai 12/elytrigia repens population, the Yangmai 12 provides an effect of increasing spike length, the locus provides a contribution rate of 9.01-12.85% for phenotype, and the additive effect is 4.02-9.47 (shown in figure 1 and table 1), and is a new spike length locus through comparison with the prior study.

TABLE 1 ear Length QTL positioning results of Yangmai 12/elytrigia repens 1

Annotation: ^a e1, E2, E3 and E4 represent yield nursery, me, respectively, of 2019 Yangzhou, 2020 Sihon and 2021 Jingzhouan represents the average of all environmental data. ^b Representing the physical location based on chinese spring version 2.1. ^c Representing the usual logarithm of the maximum likelihood function. ^d Representing the phenotype contribution rate. ^e Representing additive effects (negative values represent the allele of increased spike length from elytrigia repens # 1, positive values represent the allele of increased spike length from Yangma 12).

Example 2 clear the relationship of ear Length QTL with ear Length, thousand grain weight and scab resistance

The effect of this ear length QTL on ear length, thousand grain weight and scab resistance was analyzed using the Mean value of qsl.yaas-5B flanking marker (AX 110581004) with ear length, thousand grain weight, average disease spike number on earth surface inoculation (PIS) and average disease spike number on sporulation fluid inoculation (PSS) (the Mean value of data from the vanity test bases 2020 and 2021 in the lower river region of Jiangsu), and the results showed that qsl.yaas-5B significantly increased ear length while also significantly increased thousand grain weight and decreased PIS and PSS values, using the higher value ear length locus (table 2).

TABLE 2 analysis of the Effect of yaas-5B on thousand kernel weight and scab resistance (Mean value)

Annotation: mean represents the average value. PIS: identifying average disease spike rate by representative soil surface inoculation method; PSS: average disease spike rate was identified on behalf of the sporulation fluid. 'and' represent P <0.05 and P <0.01, respectively.

EXAMPLE 3 development of KASP markers linked to QSL. Yaas-5B

The above results indicate that allelic variation of QSL.yaas-5B, which increases spike length, has a significant synergistic effect on thousand kernel weight and scab resistance. We used the wheat reference genome information to convert the flanking SNP marker AX110581004 of this locus peak interval to the KASP marker KASP_Q.5B. The primer sequences of KASP_Q.5B are shown in Table 3.

Table 3KASP_Q.5B primer sequences

Annotation: f1 and F2 are forward primers and R is a reverse primer. The competitive primer is underlined.

Preparation of KASP primer and PCR reaction

The flanking SNP of the spike length locus peak value interval with breeding value is converted into KASP mark by utilizing wheat reference genome information, and the Primer design utilizes on-line software Primer 3.0. 2 specific primers (F1/F2) and a universal primer (R) are designed for each label according to the KASP design principle, wherein a specific sequence combined with FAM fluorescence is added to the tail part of F1, and a specific sequence combined with HEX fluorescence is added to the tail part of F2. Primers were synthesized by Beijing Jiacheng Biotechnology Co.

The KASP reaction total system was 6. Mu.L, and the mixed working solution containing 2 XKASP Master Mix 3.5. Mu. L, KASP primer was 0.1. Mu.L at a concentration of 20 ng. Mu.L ^-1 2.4. Mu.L of the template DNA of (E).

The first step of the KASP reaction procedure was 94℃for 15min; the second step is 94 ℃,25s,61-55 ℃ and 1min, wherein each cycle is reduced by 0.6 ℃ for 10 cycles; the third step was 94℃for 20s,55℃for 45s, and 29 cycles were performed in total. The KASP typing results were analyzed by KASP fluorescence analyzer (LGC company, PHERAstar plus).

The RIL population together with the parent was kasp_q.5b amplified as described above. The fluorescence signal data of the KASP_Q.5B amplification product are analyzed by Kmaster Caller software to be accumulated at a position (red) close to a Y axis in a parting result fluorescence signal coordinate system, and the fluorescence signal data are the same as Yangma 12, namely, the genotype of 36 th base (SNP locus) of the flanking nucleotide sequence (such as SEQ ID NO. 4) of QSL.yaas-5B locus of the wheat is proved to be C; and fluorescence signal data of the amplified products are analyzed by Kmaster Caller software to be accumulated at a position (blue) close to an X axis in a coordinate system, and the genotype of the wheat at a QSL.yaas-5B site is proved to be T unlike the genotyping of Yangmai 12. The material is well typed, and the KASP primer group is designed successfully.

TABLE 4 results of t-test of RIL families carrying different genotypes

Annotation: ^a the different lower case letters following the numbers represent very significant differences (P<0.01)； ^b the following t values represent very significant differences (P<0.01)。

The double sample t-test using Excel 2019 shown in table 4, it can be seen that the kasp_q.5b genotype is that the family of CCs significantly increases spike length by 5.14% (P < 0.01) over the family of TTs (statistical methods are conventional in the art, and can be seen in the literature "lid jun jia, experimental statistical methods", chinese agriculture press, 9 months 2000 ", for details).

The primer group and the genotype detection system of the KASP are respectively and independently applied or simultaneously applied to the material selection of the wheat spike length property, and the effect of QSL.yaas-5B is obvious, which indicates that the KASP marker is successfully developed and can be further applied to the detection of breeding materials.

EXAMPLE 4KASP primer set breeding applications

And (3) field test: in this example, 180 parts of wheat material from various places throughout the country were used as subjects, and 180 parts of wheat material were planted in the mastery of the mastery area in Jiangsu li and Jianshi river in the year 2020 and 2021 for 2 consecutive growing seasons. 2 rows of the plants are planted in each line by adopting a random block design, each row is 25 grains, the row length is 1.5m, the row spacing is 0.30m, the two times of repetition are carried out, and the field management is carried out according to the local high-yield cultivation management. The method comprises the steps of randomly selecting 20 representative plants with similar RIL growth states at the later stage of wheat grouting, and measuring the ear length of a main ear in 6 environments, wherein the measuring method comprises the following steps: measured from the basal to the tip of the top spike of wheat, excluding the miscanthus (basal sterile spike not counted).

180 wheat varieties (lines) were genotyped using the KASP primer set obtained in example 1. The typing results are shown in FIG. 2.

The fluorescence signal data of the KASP_Q.5B amplified products are analyzed by Klumer Caller software to be gathered at a position (red) close to the Y axis in a parting result fluorescence signal coordinate system, and the position is the same as Yangma 12, namely the genotype of the wheat at 36 th base (SNP locus) of a molecular marker KASP_Q.5B flanking nucleotide sequence (such as SEQ ID NO. 4) is proved to be C, the fluorescence signal data of the amplified products are analyzed by Klumer Caller software to be gathered at a position (blue) close to the X axis in the coordinate system, and the genotype of the wheat at the SNP locus is proved to be T when the parting result is different from the parting result of Yangma 12.

TABLE 5 t-test results for test varieties (lines) carrying different genotypes

Annotation: the numbers followed by the figures indicate significant differences at P <0.05 relative to "TT".

Table 5 shows that the double sample t test of Excel 2019 shows that the ear length is increased by 3.61% (P < 0.05) when the QSL.yaas-5B locus carries Yangmai 12 allelic variation (CC) in 180 wheat varieties (lines), which is consistent with the detection result of RIL group. The primer group and the genotype detection system of the KASP are respectively and independently applied or simultaneously applied to material selection for verifying the grain length property of the wheat of the population, and the effect of QSL.yaas-5B is obvious, which indicates that the KASP marker is successfully developed and can be further applied to the detection of breeding materials.

From the above experimental results, it is not difficult to obtain: the KASP primer group is utilized to carry out PCR amplification on the wheat genome DNA, whether the wheat genome DNA carries the genotype of increasing the spike length of Yangmai 12 is judged through KASP typing, the detection method is simple to operate, the result is visual and effective, and the molecular marker assisted selection breeding work efficiency of the wheat with the spike length increased can be greatly improved by utilizing the KASP primer group.

The above detailed description describes in detail the practice of the application, but the application is not limited to the specific details of the above embodiments. Many simple modifications and variations of the technical solution of the present application are possible within the scope of the claims and technical idea of the present application, which simple modifications are all within the scope of the present application.

Claims (6)

1. A wheat spike length-related KASP molecular marker, wherein the molecular marker is located on chromosome 5B in the wheat genome as shown in SEQ ID No. 4.

2. A set of KASP primers for detecting the molecular marker of claim 1, wherein the set of KASP primers is a set of primers X1 for detecting whether the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID No.4 on chromosome 5B in the wheat genome is CC, TT, C or T, and the set of primers X1 comprises two upstream primers and one downstream primer;

the upstream primer is designed according to 36 th deoxyribonucleotide of a sequence shown as SEQ ID NO.4 on chromosome 5B in the wheat genome and an upstream sequence thereof, wherein the 3 'terminal deoxyribonucleotide of one upstream primer is C, and the 3' terminal deoxyribonucleotide of the other upstream primer is T;

the downstream primer is designed according to the downstream sequence of 36 th deoxyribonucleotide of the sequence shown in SEQ ID NO.4 on chromosome 5B in the wheat genome.

3. The KASP primer set according to claim 2, wherein the set of primers X1 consists of an upstream primer as shown in SEQ ID No.1, SEQ ID No.2 and a downstream primer as shown in SEQ ID No. 3.

4. Use of the molecular marker of claim 1 or the KASP primer set of any of claims 2-3 in any of the following:

(A) Identifying or assisting in identifying the wheat spike length character;

(B) Predicting or comparing the wheat spike length character to be detected;

(C) Selecting or screening wheat single plants or lines or varieties with wheat spike length characters;

(D) Preparing a product for identifying or assisting in identifying the wheat spike length trait;

(E) Preparing the products of wheat single plants or strains or varieties for breeding or screening the wheat spike length characters.

5. The method comprises the following steps:

method A: a method for comparing the length characteristics of wheat ears to be tested, comprising the following steps (A1) or (A2):

(A1) Detecting whether the 36 th genotype of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the wheat genome is CC or TT or CT;

(A2) The wheat ear length to be tested was determined as follows: the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome is CC, and the wheat to be detected has allelic variation for increasing the spike length;

method B: a method for breeding or screening wheat single plants or strains or varieties with wheat spike length characters comprises the following steps:

(B1) Detecting whether the 36 th genotype of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the wheat genome is CC or TT or CT;

(B2) Selecting wheat to be detected, of which the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome is homozygote of C, as a parent for breeding, and selecting wheat of which the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in each generation of breeding is homozygote of C, so as to finally obtain a wheat single plant or strain or variety with relatively long wheat spike length;

(B3) Selecting the wheat to be detected, of which the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome is a homozygote of T, as a parent for breeding, and selecting the wheat of which the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in each generation of breeding is a homozygote of T, thereby finally obtaining a wheat single plant or strain or variety with relatively short spike length.

6. The method according to claim 5, wherein the specific operations of step (A1) or step (B1) are:

PCR amplification of the genomic DNA of wheat to be tested using the primer set according to any one of claims 2 to 3, fluorescent signal scanning of the amplified product, analysis of the scanned data, and determination of the 36 th deoxyribonucleotide type as shown in SEQ ID NO.4 on chromosome 5B in the wheat gene to be tested:

if the fluorescence signal data of the amplified product of the wheat to be detected shows red, the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome of the wheat to be detected is a homozygote of C;

if the fluorescence signal data of the amplified product of the wheat to be detected shows blue color, the 36 th deoxyribonucleotide of the molecular marker shown in SEQ ID NO.4 on chromosome 5B in the genome of the wheat to be detected is a homozygote of T.