3348 results about "Chromosome" patented technology

The invention relates to the technical field of molecular markers, and discloses an SNP (Single Nucleotide Polymorphism) molecular marker related to the litter size character of pigs and application of the SNP molecular marker. The SNP molecular marker is located at a 34977540bp site of a chromosome 2 of an international pig reference genome Sscrofa11.1 version, and the nucleotide sequence of the site is G or A and is located in an exon region of an LUZP2 gene. The invention also discloses an application of the SNP molecular marker in breeding of the litter size character of the boar, and provides a method for breeding or auxiliary breeding of the boar with high / low litter size based on the marker. The invention also provides a specific primer for identifying the SNP site. By applying the technologies, accurate prediction and efficient screening of the litter size of the large white pigs can be achieved, the breeding efficiency of excellent breeding pigs is remarkably improved, and the population improvement process is accelerated. The invention also provides important technical support for sustainable development of pig raising industry, also provides theoretical basis for research in related fields, and is expected to promote further development of pig genetic improvement work.

The invention belongs to the technical field of molecular biology, and particularly relates to a molecular marker related to the number of branches of medicago sativa and application of the molecular marker. The invention solves the technical problems that the traditional new variety breeding of alfalfa with a large number of branches is single plant selection according to the number of branches of breeding offspring, and the method is time-consuming, labor-consuming and low in accuracy. The technical scheme of the invention is a molecular marker related to the number of branches of medicago sativa. The specific information is as follows: chromosome: chr2; the position is 57649197; sNP (Single Nucleotide Polymorphism) typing: C / A. The invention also designs a primer combination aiming at the molecular marker, and the primer combination can be used for directly and specifically distinguishing and detecting A or C basic groups of SNP mutation sites.

The invention relates to the technical field of molecular biology and molecular markers, in particular to an SNP (Single Nucleotide Polymorphism) molecular marker located on a porcine chromosome 14 and related to porcine reproductive traits and application. The SNP site of the SNP molecular marker located on the No.14 chromosome of the pig and related to the reproductive traits of the pig corresponds to the Cgt at the 105043272th site on the No.14 chromosome of the international pig reference genome version 11.1; t mutation is carried out, and the polymorphism of the basic group at the site affects the porcine reproductive traits; wherein the reproductive performance of pigs with CC and TC genotypes is superior to that of pigs with TT genotypes. By optimizing the dominant alleles of the SNP molecular marker, the frequency of the dominant alleles can be increased generation by generation, the reproductive performance of pigs is improved, and the genetic improvement progress of the pigs is accelerated, so that the economic benefit of pig breeding is effectively improved.

The invention provides a molecular marker related to the salinity tolerance character of grass carp, an amplification primer of the molecular marker and application of the molecular marker in salt-tolerant breeding of the grass carp, and belongs to the technical field of breeding of aquatic animals. The molecular marker related to the salinity tolerance character of the grass carp is obtained by screening through whole genome association analysis (GWAS), and T / C polymorphism exists at the 25391590 site of a chromosome 3 or A / G polymorphism exists at the 9605803 site of a chromosome 10. The molecular marker is remarkably related to the salt tolerance character of the grass carp, two pairs of amplification primers are developed for the molecular marker, selective breeding of the grass carp can be assisted, salinity tolerance parents of the grass carp can be efficiently identified, and the salt tolerance breeding progress of the grass carp is accelerated.

The invention belongs to the technical field of molecular biotechnology and molecular markers, and particularly relates to an SNP (Single Nucleotide Polymorphism) molecular marker located on a chromosome 2 and related to abnormal delivery traits of sows and application of the SNP molecular marker. An SNP site of the SNP molecular marker corresponds to Cgt at the 23330829bp position on a chromosome 2 of an international pig reference genome version 11.1; and the polymorphism of the basic group at the site affects the abnormal delivery character of the sow. The method solves the problem of genetic improvement of abnormal delivery of sows by means of molecular breeding, and can increase the frequency of dominant alleles generation by generation, reduce the occurrence rate of abnormal delivery of sows and improve the reproductive performance of sows by optimizing the dominant alleles of variation sites. The pig genetic improvement progress is accelerated, so that the economic benefit of breeding pig breeding is effectively improved.

The invention discloses a UUV cluster dynamic task planning method based on a multi-target genetic algorithm, a program, equipment and a storage medium, and belongs to the field of underwater multi-UUV cooperative detection of multiple targets. According to the method, firstly, for path planning of regional task points, chromosome representation is completed through sequential coding, chromosomes are selected and ranked randomly, and the chromosome with the highest fitness value is selected from each group; then, in each group of the current population, selecting an optimal parent individual to carry out crossover and mutation operations so as to improve the quality of offspring individuals, and carrying out updating to obtain a next-generation population; and finally, obtaining a plurality of optimal individuals, and outputting a task planning path result. Dividing the search area into a plurality of task sub-areas, and completing the dynamic task planning of the UUV cluster according to the target distribution condition of the sub-areas and the condition of each UUV. According to the method, the search strategy can be adjusted in real time according to the real-time detection result and the environment change, so that the target distribution non-uniformity and the cluster efficiency difference are effectively relieved.

The invention discloses a macrobrachium rosenbergii iridovirus disease resistance-related SNP (Single Nucleotide Polymorphism) site, a site combination and application thereof, and belongs to the field of aquatic organism breeding. According to the invention, SNP loci related to resistance of the macrobrachium rosenbergii iridovirus disease are successfully screened through whole genome association analysis, and the SNP loci are respectively located at a 9574545th base of a chromosome 10 of the macrobrachium rosenbergii and a 26491028th base of a chromosome 14 of the macrobrachium rosenbergii. Aiming at the two SNP sites, an SNP site combination related to the resistance of the macrobrachium rosenbergii iridovirus disease is further developed, and macrobrachium rosenbergii iridovirus disease resistant individuals can be screened by detecting the SNP site combination. Therefore, the SNP molecular marker provided by the invention can be used for macrobrachium rosenbergii molecular marker assisted breeding, accelerates disease-resistant macrobrachium rosenbergii variety breeding, and provides a reference basis for disease-resistant breeding work of macrobrachium rosenbergii.

The invention belongs to the field of SNP (Single Nucleotide Polymorphism) detection, and particularly provides an SNP molecular genetic marker related to a sheep horn length character and a kit for detecting the SNP molecular marker. The kit provided by the invention is used for performing polymorphism detection on the SNP molecular genetic marker, namely the 30991957th site of the 10th chromosome, screening and determining the horn length character of the sheep, and selecting the horn length character to breed or assist in breeding horn-free sheep individuals, so that the collection of high-quality horn-free Tibetan sheep variety germplasm resources can be ensured, and the kit has a very excellent application prospect.

The invention relates to an STON1 gene molecular marker primer related to chicken double-yolk egg traits and application of the STON1 gene molecular marker primer, and belongs to the technical field of biology. The STON1 gene molecular marker is a 7867409th basic group of a chicken reference genome GRCg7b version chromosome 3, the basic group is mutated into A or G, and the genotypes are A / A, A / G and G / G. The double-yolk egg ratio of the G / G genotype chicken is higher than that of the A / G and A / A genotype individuals, and the double-yolk egg ratio of the A / G genotype chicken is higher than that of the A / A genotype individuals. A forward and reverse primer pair is used for amplifying a fragment containing the molecular marker site, Sanger sequencing is carried out on an amplification product, the genotype of an individual is rapidly and accurately identified to serve as a genetic marker for chicken breeding, and the chicken with the higher proportion of double-yolk eggs is bred; the double-yolk egg traits can be efficiently and accurately detected, the breeding accuracy and breeding efficiency of the chicken double-yolk egg proportion are improved, and the method has important value for chicken breeding and production.

The invention discloses an SNP molecular marker related to the conception rate of young cows, a detection product and application of the SNP molecular marker, and belongs to the technical field of dairy cow breeding markers. The SNP molecular marker is chr6: g. 103355581Cgt, and the SNP molecular marker is a molecular marker. The method comprises the following steps of: taking a bovine reference genome version UMD3.1 as a standard for a coordinate position, numbering Assessment in NCBI (National Center of Biotechnology Information) as GCF000003055.6, and numbering a chromosome as AC 000163.1; the young cows are cows which are 12-24 months old and do not lay calves. By detecting the genotype of the SNP site, the conception rate condition can be effectively judged, parent individuals with the higher young cow conception rate can be screened, early selection of genotype individuals with the high young cow conception rate is achieved, the frequency of the genotype with the high young cow conception rate in a dairy cow group is increased, and the reproduction rate of the dairy cow group is increased; the service life of cows is prolonged, the treatment cost is saved, the breeding cost is reduced, and the pasture income is increased.

Provided herein are methods and compositions for expressing Otoferlin, e.g., utilizing adeno-associated viral (AAV) particles. Further provided herein are compositions of AAV particles comprising one or more polynucleotides encoding Otoferlin are codon optimized for expression in human cells. Such methods and compositions may be useful for treatment of diseases and disorders such as Deafness, Autosomal Recessive 9 (DFNB9). Also provided are kits comprising such compositions.

The invention belongs to the technical field of aquatic biotechnology and molecular marker-assisted breeding, and particularly relates to a cynoglossus semilaevis vibrio harveyi-resistant KASP molecular marker combination and application thereof in cynoglossus semilaevis disease-resistant breeding. The KASP molecular marker combination comprises three SNP (Single Nucleotide Polymorphism) loci which are respectively positioned at 17314099, 17325496 and 17355989 loci of the 14 # chromosome of the cynoglossus semilaevis, when the genotypes of the three SNP loci are respectively CC, AA and GG, the disease resistance of the cynoglossus semilaevis is high, and the invention also provides a primer for detecting the genotype polymorphism of the SNP loci. By utilizing the KASP molecular marker combination, the vibrio harveyi resistance genotype in a cynoglossus semilaevis breeding population can be quickly detected, and disease-resistant individuals are screened, so that the disease-resistant breeding efficiency of the cynoglossus semilaevis is greatly improved, and a new variety of the cynoglossus semilaevis with strong disease resistance can be quickly cultivated.

The invention discloses a KASP molecular marker for identifying soybean hundred-grain weight and application thereof, and relates to the technical field of biology and application of an SNP locus, the SNP locus takes a soybean Wm82. A2. V1 genome sequence as a reference genome, the SNP is the 16321243th SNP on a soybean 11 # chromosome, and the SNP is the 16321243th SNP on the soybean 11 # chromosome. Corresponding to the 20th basic group from the 5'terminal of the sequence shown in SEQ ID NO: 1, when the locus is CC homozygosis, the corresponding genotype is A; when the locus is TT homozygous, the corresponding genotype is B; according to the application, soybeans with different hundred-grain weights are screened or screened in an auxiliary mode, and the different hundred-grain weights of the soybeans are as follows: the homozygous soybeans with the genotype A are higher than or candidate to be higher than the homozygous soybeans with the genotype B. The molecular marker has important theoretical significance and economic value for molecular marker-assisted selection of soybean germplasm or breeding progeny materials with high hundred-grain weight.

The invention belongs to the technical field of crop genetic breeding, and particularly relates to a rice hybrid male sterility site HMS10 co-segregation molecular marker and application thereof. The method comprises the following steps: hybridizing and backcrossing an anti-thermo-sensitive type genic male sterile line Yannong S serving as a female parent with a normal fertile material Yannong HB (serving as a recurrent male parent), finely positioning to a site HMS10 for controlling hybrid male sterility of rice in a physical interval of-60kb of a chromosome 10 of the rice by utilizing a high-generation backcross large population, and developing a co-separation molecular marker IDHMS10. The molecular marker IDHMS10 is utilized, through a molecular breeding strategy, a positive temperature-sensitive male genic male sterile line Quan 211S with excellent comprehensive agronomic traits is transformed into a practical rice hybrid male sterile line Quan 211HS with fertility not affected by light and temperature, and the IDHMS10 is used for purity identification of the hybrid male sterile line, so that the molecular marker IDHMS10 has great significance in solving the seed production risk of two-line hybrid rice and improving the yield of the hybrid male sterile line. And the method has important significance in enriching practical sterile resource types and the like.

The invention relates to the technical field of bee breeding, in particular to an SNP (Single Nucleotide Polymorphism) molecular marker and application of the SNP molecular marker to identification of a honeybee shin length character. The SNP molecular marker is located at the 8751308th site of the 14 # chromosome of the bee, and the polymorphism is T / C. Based on a whole genome association analysis result of bee sample data, the SNP molecular marker which is very related to the character of the shin segment length of the bee is obtained through screening, and a polymorphism detection result of the SNP molecular marker can reflect the shin segment length of the bee to be detected. The SNP molecular marker provided by the invention can be applied to breeding bees with different tibia lengths, is beneficial to improving the pollen collection efficiency of bees, and has important value.

The invention provides a KASP molecular marker related to a corn ear height character under a drought condition and application of the KASP molecular marker, and belongs to the technical field of molecular genetics. The SNP marker site related to the ear height character under the drought condition and having polymorphism is obtained through whole genome association analysis, the SNP marker site refers to a corn B73 RefGenv4 genome, when nucleotide polymorphism T / C exists at the position 147243591 of a 10 # chromosome, the SNP marker site is a dominant character, and nucleotide sequences used for amplifying a KASP molecular marker primer group are shown as SEQ ID NO.1-3. Gene typing identification can be rapidly, simply and efficiently carried out by utilizing a KASP typing technology, enzyme digestion and electrophoresis are not needed, accurate identification and selection can be carried out in a seedling stage, a large amount of breeding workload can be reduced, the period of high-ear-position breeding selection can be shortened, and the method can be used for high-ear-position molecular marker-assisted breeding of corn.

The invention relates to a linked KASP molecular marker of a wheat stripe rust resistance gene YrBN1 and application of the molecular marker. The KASP molecular marker is XK1D-8; the KASP molecular marker and a wheat stripe rust resistance gene YrBN1 are co-localized on a wheat 1DS chromosome, the nucleotide sequence of XK1D-8 is as shown in SEQ ID NO.1, the 100th basic group from the 5'end of the nucleotide sequence is an SNP site, and the polymorphism of the SNP site is C / A. The KASP molecular marker is closely linked with the stripe rust resistant gene YrBN1, can accurately identify wheat stripe rust resistant plants, and is of great significance to wheat germplasm resource stripe rust resistant gene screening, wheat stripe rust resistant material creation or molecular assisted breeding.

The invention discloses a soybean nodulation number related major single nucleotide polymorphism (SNP) site and application thereof, the SNP site is positioned on a soybean chromosome 2, the physical distance of the SNP site in a soybean genome version number Glycine max Wm82.a2.v1 is Chr0243129492, the SNP site corresponds to a 20th basic group of a sequence shown as SEQ ID NO.1, when the site is T / T homozygosis, the corresponding genotype is A, when the site is T / T homozygosis, the corresponding genotype is B, and when the site is T / T homozygosis, the corresponding genotype is C; when the site is C / C homozygous, the corresponding genotype is B; the number of root nodules is as follows: the genotype A homozygous soybean is greater than or candidate to be greater than that of the genotype B homozygous soybean. By detecting the SNP, a tested soybean population can be accurately divided into a low root nodule number (C / C) and a high root nodule number (T / T). Therefore, the molecular marker can be used as a basis for preliminarily identifying the number of soybean nodules, has high efficiency and applicability such as simplicity in operation, low cost and short consumed time, and has important values for digging germplasm of high-nodulation soybeans, solving the problem of nitrogen fertilizer abuse and promoting sustainable development of agriculture.

The invention belongs to the field of pepper breeding and molecular biology, and discloses a KASP molecular marker closely linked with a pepper fruit color gene CaCHL1, the gene of pepper zunla-1 is used as a reference gene, and the single nucleotide polymorphism at the 13072545th basic group on a pepper chromosome 5 is subjected to basic group G-C replacement. The invention further discloses a primer and a kit for identifying the KASP molecular marker closely linked with the pepper fruit color gene CaCHL1 and application of the primer and the kit in identifying pepper fruit color types or molecular assisted breeding. The screened KASP molecular marker can be directly used for identifying the pepper fruit color, then auxiliary breeding is carried out by depending on the molecular marker, the problems that conventional breeding is long in period and prone to being influenced by the environment can be effectively solved, and the KASP molecular marker has important significance in pepper fruit color breeding practice and research on fruit color change and regulation and control mechanisms.

The invention belongs to the field of SNP (Single Nucleotide Polymorphism) detection, and particularly provides an SNP molecular marker related to a sheep horn length character and a kit for detecting the SNP molecular marker. The kit provided by the invention is used for performing polymorphism detection on the SNP molecular genetic marker, namely the 30947874th site of the 10th chromosome, screening and determining the horn length character of the sheep, and selecting the horn length character to breed or assist in breeding horn-free sheep individuals, so that the collection of high-quality horn-free Tibetan sheep variety germplasm resources can be ensured, and the kit has a very excellent application prospect.

The invention discloses an SNP molecular marker related to drought resistance of corn and application of the SNP molecular marker, and relates to the field of agricultural molecular biology. The SNP molecular marker comprises at least one of a first SNP molecular marker and a second SNP molecular marker; the first SNP molecular marker is located at a basic group at a 97605381 site of a chromosome 9 of a corn reference genome Zeamas.AGPv4, and the polymorphism of the first SNP molecular marker is C / T; the second SNP molecular marker is located at the basic group of the 97604011 site of the No.9 chromosome of the corn reference genome Zeamas.AGPv4, and the polymorphism is C / T. The SNP molecular marker disclosed by the invention has the characteristics of high specificity, high sensitivity, high resolution and high typing quality; the drought resistance of the corn material can be quickly judged according to the genotype, and the method has wide application universality and can be used for corn breeding.

The present invention relates to the technical field of molecular markers for maize resistance to stalk rot and genetic breeding, and in particular, to a QTL related to maize resistance to stalk rot, SNP molecular markers closely linked with the QTL, and a use of the SNP molecular markers. Provided is a QTL related to maize resistance to stalk rot, wherein the QTL is located on maize chromosome 10. Also provided are SNP molecular markers Ks4 and Ks6 closely linked with a QTL site for maize resistance to stalk rot. By detecting the SNP molecular markers, the genotype of a maize material under test can be accurately identified in a high-throughput manner, a material resistant to stalk rot is selected, and phenotype identification and assisted screening of the maize resistance to stalk rot can also be carried out in a seedling stage, thus significantly reducing production cost and significantly enhancing the efficiency of breeding maize resistant to stalk rot.

The invention belongs to the technical field of crop genetic breeding, and relates to a linked molecular marker of a peanut hypocotyl elongation related gene locus, an identification method and application of the linked molecular marker. The primer pair is C2-15-F / R, and the sequence of the primer pair is as shown in SEQ ID NO. 1 and SEQ ID NO. 2; by designing an InDel marker C2-15, the peanut hypocotyl length character can be quickly distinguished by using a primer to amplify a target band and using polyacrylamide gel electrophoresis detection. The identification method is more accurate and convenient, has good repeatability, can efficiently distinguish the phenotype and genotype of an individual, shortens the experiment process, has the advantages of simple and feasible operation steps and the like, and saves expenditure. The method disclosed by the invention has important application value in the breeding work aspects such as peanut hypocotyl elongation character related gene positioning, genotype typing and later cultivation of excellent peanut varieties.

Among other things, the present disclosure pertains to methods and compositions related to phasing of allelic variants of genetic loci. Phasing of allelic variants of genetic loci on an individual patient's chromosomes is highly valuable for many purposes, including patient stratification for allele-specific therapeutics.

The invention discloses a whole-genome low-density chip for breeding high-yield and long-life characters of dairy cows and application of the whole-genome low-density chip. The invention firstly discloses a whole-genome low-density chip for breeding the high-yield and long-life character of the dairy cow, the whole-genome low-density chip comprises 10000 SNP (Single Nucleotide Polymorphism) loci, ARS-UCD1.2 is used as a reference genome, and the information of the 10000 SNP loci is shown in a table 6. The invention further discloses application of the whole-genome low-density chip. The 10,000 SNP loci contained in the whole genome low-density chip are uniformly distributed on chromosomes, cover the whole genome and important character loci, can effectively improve the longevity and the accuracy of milk yield breeding, and can be applied to gene screening, gene positioning, marker-assisted breeding and the like. In addition, the detection cost of the low-density chip is greatly reduced, and the low-density chip is more suitable for commercialized dairy farms and has important significance on dairy cow breeding and dairy cow group improvement.

The invention relates to a molecular marker related to the content of 2-acetyl-3-methylpyrazine in pig muscle and application of the molecular marker, belonging to the technical field of determination or inspection methods of enzymes, nucleic acids or microorganisms. The technical problem to be solved by the invention is to provide a molecular marker related to the content of 2-acetyl-3-methylpyrazine in pig muscle. In order to solve the technical problem, the molecular marker provided by the invention is obtained through genome-wide association (GWAS) analysis, the nucleotide sequence of the molecular marker is as shown in SEQ ID NO: 1, and the molecular marker has an Agt at the 6328556 position of a chromosome 9 of a pig genome; a nucleotide single base of G is mutated, and the mutation obviously affects the content of 2-acetyl-3-methylpyrazine in pig muscles. By detecting the genotype of a to-be-detected pig at the SNP site, early selection of the content of 2-acetyl-3-methylpyrazine in pig muscles can be realized.

The invention belongs to the technical field of aquatic animal molecular markers and aquatic genetic breeding, and particularly relates to an SNP (Single Nucleotide Polymorphism) molecular marker remarkably related to growth traits of grass carp and application of the SNP molecular marker. The SNP molecular marker is located at the position of 23608308bp of the eleventh chromosome (SLG1123608308) of the grass carp, and is Tgt; and A basic group mutation. Experiments show that the SNP molecular marker developed by the invention has significant influence on four growth traits (Plt; 0.05), and the allele A has more excellent growth traits. The invention discloses application of an SNP (Single Nucleotide Polymorphism) molecular marker, an amplification primer or a kit in breeding grass carp with excellent growth traits. The SNP molecular marker provided by the invention is not limited by the age, sex and the like of the grass carp, can be used for breeding grass carp varieties with excellent growth traits, and even can be accurately screened after being hatched, so that the breeding process of the grass carp varieties with excellent growth traits is greatly accelerated.

The invention discloses an SNP (Single Nucleotide Polymorphism) molecular marker related to the daily gain character of a pig. The SNP molecular marker is a Ggt (Glutathione Ggt) located at the position of 160773437bp of a first chromosome of a pig genome Ensembl Sscrofa11.1 version; a mutation. Through the SNP molecular marker, the SNP molecular marker can be applied to breeding of the daily weight gain character of the Duroc long commercial pigs, so that the daily weight gain character of the Duroc long commercial pigs is improved, the growth performance and the slaughter weight of the Duroc long commercial pigs are improved, and the economic value and the economic benefit of the Duroc long commercial pigs are improved. And the variety of the Duroc long commercial pigs can be improved, the daily gain character of the variety is further improved, improved variety breeding is performed, and the market competitiveness of the Duroc long commercial pigs is improved. In addition, due to the fact that the Duroc long hybrid population is adopted as a research object, the Duroc long hybrid population can also serve as a reference population of a male parent Duroc purebred population, and reference and application values are improved for breeding of male parent Duroc boars in daily gain.

The invention relates to the field of biological detection, in particular to a mini STR (short tandem repeat) double-multiplex amplification system and kit for degrading 25 gene loci of a sample. The invention provides a kit. The kit comprises 25 gene loci; the 25 gene loci comprise 23 autosomal STR gene loci, one sex gene locus and one Yindel gene locus. According to the kit provided by the invention, the primers are divided into a group A and a group B, and all gene loci are miniS TR gene loci on the basis of using current mainstream instruments and equipment. The two tubes of primers use the same experiment condition, and amplification and electrophoresis can be carried out at the same time. Compared with the existing miniSTR kit, the kit disclosed by the invention can be independently amplified and does not need to be combined with other autosomal STR kits for use, and the typing of 25 gene loci can be obtained through one-time detection. The effective detection rate of degraded samples is greatly improved, and technical support is provided for detection of difficult cases.

The invention provides application of a Zm00001eb378820 gene in molecular marker-assisted breeding for regulating and controlling the hundred-grain weight of corn grains, and relates to the technical field of agricultural biology. A backbone maize inbred line Ye107 is used as a male parent and hybridized with three excellent inbred lines (D39, R-2-1-1 and YML1218), a multi-parent group with remarkable hundred-grain weight difference is constructed, and SNP27712538 positioned on a chromosome 9 is a remarkable associated site by measuring hundred-grain weight phenotype data in multiple environments and combining high-density SNP (Single Nucleotide Polymorphism) markers, GWAS analysis and QTL (Quantitative Trait Loci) positioning. And the functional gene Zm00001eb378820 which is closely related to the regulation and control of the corn hundred-grain weight is excavated. A new insight is provided for a genetic regulation mechanism of the corn hundred-grain weight, and a key target spot is provided for breeding of high-yield corn varieties, so that the breeding efficiency is remarkably improved.