HIGH-EFFICIENCY ZEA MAYS L. BREEDING METHOD BASED ON INDIVIDUAL PLANT EVALUATION AND GENOME-WIDE SELECTION (GWS)

Abstract

A high-efficiency Zea mays L. breeding method based on individual plant evaluation and genome-wide selection (GWS) includes: S1. in a first cropping season, pollinating a Zea mays L. female parent with multiple male parents; S2. in a second cropping season, subjecting hybrid seeds to single-seed sowing, conducting individual plant selection, and evaluating target traits; S3. identifying a parent of a selected cross combination; S4. subjecting a target trait of a cross combination to genome-wide prediction; S5. selecting an excellent cross combination according to a predicted target trait; and S6. subjecting the selected excellent cross combination directly to variety registration or to further evaluation. The high-efficiency Zea mays L. breeding method provided by the present disclosure greatly reduces a quantity of cross combination seeds obtained in the first cropping season and a planting scale of the cross combinations in the second cropping season, and effectively reduces the breeding cost.

Description

TECHNICAL FIELD

The present disclosure relates to a high-efficiency Zea mays L. breeding method based on individual plant evaluation and genome-wide selection (GWS).

BACKGROUND

Zea mays L. is the main field crop worldwide, and the breeding of new high-yield Zea mays L. varieties is one of the important ways to increase a yield. According to the conventional Zea mays L. breeding method, a Zea mays L. breeding unit usually needs to make thousands or even tens of thousands of cross combinations every year and evaluate these cross combinations through multiple-row plots at multiple locations in the next cropping season to screen out a few excellent cross combinations for variety registration. In this process, a large number of useless cross combinations need to be produced and subjected to multi-location evaluation, which consumes a lot of manpower, material resources, and financial resources, and is not conducive to the control of a breeding cost by a breeding unit. In addition, the cross combinations obtained in breeding practice only account for a small part of a theoretical quantity, and thus excellent cross combinations may not be made and screened out, resulting in a waste of excellent genetic resources.

SUMMARY

In order to solve the problem in the prior art that excellent cross combinations may not be made and screened out because the cross combinations obtained in Zea mays L. breeding only account for a small part of a theoretical quantity, which results in a waste of excellent genetic resources, the present disclosure provides a high-efficiency Zea mays L. breeding method based on individual plant evaluation and GWS.

To solve the above technical problem, the present disclosure provides the following technical solution.

A high-efficiency Zea mays L. breeding method based on individual plant evaluation and GWS is provided, including the following steps:

S1. in a first cropping season, pollinating a Zea mays L. female parent with multiple male parents;

S2. in a second cropping season, subjecting hybrid seeds to single-seed sowing, conducting individual plant selection, and evaluating target traits, where when the hybrid seeds are subjected to single-seed sowing, a female parent corresponding to a hybrid seed subjected to single-seed sowing is recorded; and the sowing density, soil conditions, field management measures, and other factors affecting the growth of individual plants should be consistent;

S3. identifying a parent of a selected cross combination, which specifically includes the following steps:

S31. screening genomic DNAs (gDNAs) of all male and female parents in the first cropping season to obtain molecular markers used to identify parental genotypes;

S32. subjecting gDNA templates of all male and female parents in the first cropping season and the hybrid seeds to polymerase chain reaction (PCR) amplification with the molecular markers, and recording genotypes;

S33. deriving all possible cross combination genotypes according to genotypes of all male and female parents in the first cropping season; and

S34. comparing genotypes of the hybrid seeds with all cross combination genotypes derived, and recording a matching rate of identical genotype loci, where if a selected cross combination and a derived cross combination have the highest matching rate of identical genotype loci, a parent of the derived cross combination is a parent of the selected cross combination;

S4. subjecting a target trait of a cross combination to genome-wide prediction, where

S4 specifically includes the following steps:

S41. genotyping a parent of a cross combination identified in S3, and inferring a genotype of the corresponding cross combination according to a genotype of the parent;

S42. using target trait averages and genotypes of cross combinations evaluated in S2 to fit a genome-wide prediction model; and

S43. predicting target traits of all possible cross combinations according to the fitted genome-wide prediction model;

S5. selecting an excellent cross combination according to a predicted target trait; and

S6. subjecting the selected excellent cross combination directly to variety registration or to further evaluation.

The identification of a genotype of a parent and the derivation of a genotype of a cross combination are not limited to the second cropping season and can be completed in the first cropping season.

In theory, as long as the genotype information of Zea mays L. inbred lines and the phenotypic values (such as yield, quality, and resistance) of some cross combinations are acquired, genomic estimated breeding values (GEBVs) of corresponding phenotypes of all remaining cross combinations can be predicted, and according to prediction results, excellent combinations can be selected for variety registration, which avoids the evaluation of a large number of useless combinations. Therefore, GWS is conducive to the development of the high-efficiency Zea mays L. breeding technology, which can effectively reduce the breeding cost and has an important application value for the Zea mays L. breeding of breeding companies at a controlled cost.

The present disclosure has the following beneficial effects:

The present disclosure proposes for the first time the combination of individual plant trait evaluation and GWS for Zea mays L. cross combinations, which can efficiently select a target cross combination and reduce the breeding cost.

Because it is not necessary to conduct multiple-row plot evaluation on the cross combinations, a quantity of cross combination seeds obtained in the first cropping season and a planting scale of the cross combinations in the second cropping season are greatly reduced and the breeding cost is effectively reduced.

The established GWS can predict cross combinations that are not produced to screen excellent combinations, which can reduce the waste of excellent genetic resources and improve the selection efficiency of breeding practice.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing is used to further illustrate the present disclosure and constitutes a part of the specification. The accompanying drawing, together with the example of the present disclosure, is provided to explain the present disclosure, but does not constitute a limitation to the present disclosure.

FIGURE is a flow chart of the high-efficiency Zea mays L. breeding method based on individual plant evaluation and GWS.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The preferred example of the present disclosure is described below with reference to the accompanying drawing. It should be understood that the preferred example described herein is only used to illustrate and explain the present disclosure, rather than to limit the present disclosure.

EXAMPLE

A high-efficiency Zea mays L. breeding method based on individual plant evaluation and GWS was provided, including the following steps:

(1) Production of Cross Combinations

In the winter of 2018, 10 female parent inbred lines and 6 male parent inbred lines were selected and planted in Hainan. The female parent inbred lines were planted with two rows on each ridge, and the male parent inbred lines were mixed-planted with two rows on each ridge. A mixed male parent inbred line row was planted following every 2 adjacent female parent inbred line rows. The tassel was removed from a female parent material before silking, and then the female parent material was open-pollinated. Seeds of a same female parent inbred line were harvested together and sown in the next season.

(2) Single-Seed Sowing of Cross Combinations

Seeds of the cross combinations harvested in the last season were sown in Fuyang, Anhui in the summer of 2019. A test field was flat and had uniform soil fertility. 300 hybrid seeds of a same female parent were randomly selected and directly sown independently at a same density (25 seeds/row). 8 commercial hybrid seeds (parents thereof were among the 16 parents) were sown as controls. Field management during the growth of Zea mays L. were the same.

(3) Trait Evaluation of Individual Hybrid Plant

At a maturity stage of Zea mays L., breeders selected 134 individual hybrid plants with excellent comprehensive traits based on experience and harvested. The amount of hybrid derived from the same female parent ranges from 1 to 37. Single ear threshing was conducted, and resulting grains on each ear were oven-dried and weighed to obtain a grain weight per ear.

(4) Identification of Parents of Cross Combinations

gDNA was extracted from leaves of 134 selected cross combination plants, 8 commercial hybrid controls, and 16 parents. All cross combinations and parents were subjected to PCR amplification using 33 molecular markers screened from the parents, and amplification products were analyzed by agarose gel electrophoresis. For each molecular marker, a short band was recorded as A, a long band was recorded as B, a double-band was recorded as H, and a missing was recorded as N. A genotype of a cross combination was derived according to the following criteria: when either parent of a cross combination is N, a genotype of the cross combination is recorded as N; when genotypes of both parents of a cross combination are both A or B, a genotype of the cross combination is A or B; and when genotypes of both parents of a cross combination are respectively A and B, a genotype of the cross combination is H. Theoretically, a maximum of 60 cross combinations can be obtained from the 10 female parent inbred lines and the 6 male parent inbred lines. The genotypes of 33 marker loci in 142 cross combinations were compared with the derived genotypes of 60 cross combinations, and a number of identical genotype loci and a number of non-missing loci were recorded. A matching rate of identical genotype loci was calculated as follows: matching rate of identical genotype loci (%)=number of identical genotype loci/number of non-missing loci×100. When a matching rate of identical genotype loci is the highest, a parent of a derived genotype cross combination was considered as a parent of a corresponding selected cross combination (Table 1). 8 commercial hybrids as controls were each matched to a correct derived cross combination, which verified the accuracy of the method for identifying a parent. According to analysis, the selected 134 cross combinations were actually 39 different cross combinations, and 1 to 14 plants were selected for each cross combination (Table 1).

(5) Genome-Wide Prediction of Target Traits

The 16 parent inbred lines were genotyped using the illumina MaizeSNP50 BeadChip. Missing and heterozygous single nucleotide polymorphism (SNP) loci and SNP loci with minor allele frequency (MAF) of less than 0.05 were filtered out, and then the remaining 31,260 SNP loci were used to derive genotypes of the 60 cross combinations. Derivation criteria were as follows: when genotypes of both parents of a cross combination are both A or B, a genotype of the cross combination is A or B; and when genotypes of both parents of a cross combination are respectively A and B, a genotype of the cross combination is H. The derived genotypes of 39 cross combinations and an average grain weight per ear of the cross combinations were fitted by the R-rrBLUP v4.6 package to obtain a molecular marker effect. According to the rrBLUP model, GEBVs of grain weight per ear of the 60 cross combinations could be estimated with the deduced genotypes and 31,260 SNP molecular marker effects of the 60 cross combinations to realize the genome-wide prediction of target traits.

(6) Selection of Excellent Cross Combinations

The GEBVs of grain weight per ear of the 60 cross combinations were ranked from largest to smallest (Table 2), and the top 10% of the cross combinations were selected for subsequent breeding (the selection criteria were determined by breeders). The top 10% of the cross combinations include two commercial Zea mays L. varieties, of which Xianyu 335 is currently a Zea mays L. variety with the largest planting area in China. The results indicate the high efficiency of GWS. According to the results, breeders can determine whether the selected cross combinations are subjected directly to variety registration or to further evaluation.

TABLE 1
Parental identification of cross combinations
					Highest
					matching rate
	Corresponding		Number of	Number of	of identical
Individual	commercial hybrid		identical	non-missing	genotype
plant No.	or female parent	Matched derived cross combination	loci	loci	loci (%)
DFDM19001-CK	Denghai 605	605 female parent × 605 male parent	24	33	72.7
DFDM19002-12	605 female parent	605 female parent × B6232	27	33	81.8
DFDM19002-17	605 female parent	605 female parent × B6232	29	33	87.9
DFDM19002-18	605 female parent	605 female parent × B6232	30	33	90.9
DFDM19002-19	605 female parent	605 female parent × B6232	31	33	93.9
DFDM19002-25	605 female parent	605 female parent × B6232	23	31	74.2
DFDM19002-27	605 female parent	605 female parent × B6232	31	33	93.9
DFDM19002-30	605 female parent	605 female parent × B6232	28	33	84.8
DFDM19002-31	605 female parent	605 female parent × B6232	27	33	81.8
DFDM19002-35	605 female parent	605 female parent × B6232	26	33	78.8
DFDM19002-26	605 female parent	605 female parent × B6275	25	33	75.8
DFDM19002-1	605 female parent	605 female parent × PH4CV	16	32	50.0
DFDM19002-16	605 female parent	605 female parent × PH4CV	20	31	64.5
DFDM19002-20	605 female parent	605 female parent × PH4CV	23	31	74.2
DFDM19002-21	605 female parent	605 female parent × 618 male parent	24	33	72.7
DFDM19003-CK	Denghai 618	618 female parent × 618 male parent	31	33	93.9
DFDM19004-1	618 female parent	618 female parent × B6211	27	33	81.8
DFDM19004-4	618 female parent	618 female parent × B6211	28	33	84.8
DFDM19004-6	618 female parent	618 female parent × B6211	32	33	97.0
DFDM19004-7	618 female parent	618 female parent × B6211	25	33	75.8
DFDM19004-10	618 female parent	618 female parent × B6211	29	33	87.9
DFDM19004-15	618 female parent	618 female parent × B6211	30	33	90.9
DFDM19004-16	618 female parent	618 female parent × B6211	32	33	97.0
DFDM19004-12	618 female parent	618 female parent × B6232	28	33	84.8
DFDM19004-17	618 female parent	618 female parent × B6232	26	33	78.8
DFDM19004-22	618 female parent	618 female parent × B6232	27	33	81.8
DFDM19004-25	618 female parent	618 female parent × B6232	27	33	81.8
DFDM19004-5	618 female parent	618 female parent × B6275	23	31	74.2
DFDM19004-20	618 female parent	618 female parent × PH4CV	29	32	90.6
DFDM19004-26	618 female parent	618 female parent × PH4CV	29	33	87.9
DFDM19004-28	618 female parent	618 female parent × PH4CV	22	32	68.8
DFDM19004-31	618 female parent	618 female parent × PH4CV	30	33	90.9
DFDM19004-33	618 female parent	618 female parent × PH4CV	31	33	93.9
DFDM19004-13	618 female parent	618 female parent × 605 male parent	19	33	57.6
DFDM19004-2	618 female parent	618 female parent × 618 male parent	31	33	93.9
DFDM19004-9	618 female parent	618 female parent × 618 male parent	24	33	72.7
DFDM19006-1	DK517 female parent	DK517 female parent × B6211	21	33	63.6
DFDM19006-2	DK517 female parent	DK517 female parent × B6211	31	33	93.9
DFDM19006-3	DK517 female parent	DK517 female parent × B6211	24	33	72.7
DFDM19006-4	DK517 female parent	DK517 female parent × B6211	31	33	93.9
DFDM19006-5	DK517 female parent	DK517 female parent × B6211	29	33	87.9
DFDM19006-7	DK517 female parent	DK517 female parent × B6211	26	33	78.8
DFDM19006-11	DK517 female parent	DK517 female parent × B6211	30	33	90.9
DFDM19006-15	DK517 female parent	DK517 female parent × B6211	26	33	78.8
DFDM19006-17	DK517 female parent	DK517 female parent × B6211	29	33	87.9
DFDM19006-21	DK517 female parent	DK517 female parent × B6211	27	33	81.8
DFDM19006-8	DK517 female parent	DK517 female parent × B6232	26	33	78.8
DFDM19006-13	DK517 female parent	DK517 female parent × B6232	30	33	90.9
DFDM19006-23	DK517 female parent	DK517 female parent × B6232	26	33	78.8
DFDM19006-44	DK517 female parent	DK517 female parent × B6232	28	33	84.8
DFDM19006-10	DK517 female parent	DK517 female parent × B6275	22	32	68.8
DFDM19006-24	DK517 female parent	DK517 female parent × B6275	32	33	97.0
DFDM19006-25	DK517 female parent	DK517 female parent × B6275	30	33	90.9
DFDM19006-28	DK517 female parent	DK517 female parent × B6275	20	30	66.7
DFDM19006-31	DK517 female parent	DK517 female parent × B6275	26	33	78.8
DFDM19006-43	DK517 female parent	DK517 female parent × B6275	28	33	84.8
DFDM19006-14	DK517 female parent	DK517 female parent × PH4CV	29	33	87.9
DFDM19006-16	DK517 female parent	DK517 female parent × PH4CV	29	33	87.9
DFDM19006-18	DK517 female parent	DK517 female parent × PH4CV	29	33	87.9
DFDM19006-20	DK517 female parent	DK517 female parent × PH4CV	30	33	90.9
DFDM19006-22	DK517 female parent	DK517 female parent × PH4CV	28	33	84.8
DFDM19006-29	DK517 female parent	DK517 female parent × PH4CV	29	33	87.9
DFDM19006-34	DK517 female parent	DK517 female parent × PH4CV	27	33	81.8
DFDM19006-35	DK517 female parent	DK517 female parent × PH4CV	28	33	84.8
DFDM19006-36	DK517 female parent	DK517 female parent × PH4CV	30	33	90.9
DFDM19006-38	DK517 female parent	DK517 female parent × PH4CV	29	33	87.9
DFDM19006-40	DK517 female parent	DK517 female parent × PH4CV	28	33	84.8
DFDM19006-41	DK517 female parent	DK517 female parent × PH4CV	25	33	75.8
DFDM19006-42	DK517 female parent	DK517 female parent × PH4CV	27	33	81.8
DFDM19006-46	DK517 female parent	DK517 female parent × PH4CV	29	33	87.9
DFDM19006-26	DK517 female parent	DK517 female parent × 618 male	26	33	78.8
		parent
DFDM19006-27	DK517 female parent	DK517 female parent × 618 male	22	33	66.7
		parent
DFDM19006-45	DK517 female parent	DK517 female parent × 618 male	29	33	87.9
		parent
DFDM19007-CK	Yayu No. 2	A7016 × B6275	21	32	65.6
DFDM19008-1	A7016	A7016 × B6211	30	33	90.9
DFDM19008-2	A7016	A7016 × B6211	29	33	87.9
DFDM19008-7	A7016	A7016 × B6211	27	33	81.8
DFDM19008-13	A7016	A7016 × B6211	27	33	81.8
DFDM19008-15	A7016	A7016 × B6211	28	33	84.8
DFDM19008-40	A7016	A7016 × B6211	28	33	84.8
DFDM19008-3	A7016	A7016 × B6232	24	33	72.7
DFDM19008-18	A7016	A7016 × B6275	25	33	75.8
DFDM19008-36	A7016	A7016 × B6275	26	33	78.8
DFDM19008-20	A7016	A7016 × PH4CV	29	33	87.9
DFDM19008-23	A7016	A7016 × PH4CV	26	33	78.8
DFDM19008-25	A7016	A7016 × PH4CV	28	33	84.8
DFDM19008-26	A7016	A7016 × PH4CV	27	33	81.8
DFDM19008-28	A7016	A7016 × PH4CV	28	33	84.8
DFDM19008-32	A7016	A7016 × PH4CV	27	33	81.8
DFDM19008-12	A7016	A7016 × 618 male parent	23	32	71.9
DFDM19008-29	A7016	A7016 × 618 male parent	29	33	87.9
DFDM19008-34	A7016	A7016 × 618 male parent	31	32	96.9
DFDM19008-38	A7016	A7016 × 618 male parent	29	33	87.9
DFDM19008-6	A7016	A7016 × B6232	18	33	54.5
DFDM19009-CK	Luyan 188	A8001 × B6211	29	33	87.9
DFDM19010-4	A8001	A8001 × B6211	26	33	78.8
DFDM19010-5	A8001	A8001 × B6211	29	33	87.9
DFDM19010-6	A8001	A8001 × B6211	29	33	87.9
DFDM19010-8	A8001	A8001 × B6211	28	33	84.8
DFDM19010-12	A8001	A8001 × B6211	28	33	84.8
DFDM19010-15	A8001	A8001 × B6211	26	33	78.8
DFDM19010-24	A8001	A8001 × B6275	20	30	66.7
DFDM19010-32	A8001	A8001 × B6275	30	33	90.9
DFDM19010-52	A8001	A8001 × B6275	30	33	90.9
DFDM19010-18R	A8001	A8001 × PH4CV	30	33	90.9
DFDM19010-22R	A8001	A8001 × PH4CV	30	33	90.9
DFDM19010-23R	A8001	A8001 × PH4CV	30	33	90.9
DFDM19010-25R	A8001	A8001 × PH4CV	30	33	90.9
DFDM19010-26R	A8001	A8001 × PH4CV	30	33	90.9
DFDM19010-28R	A8001	A8001 × PH4CV	30	33	90.9
DFDM19010-37	A8001	A8001 × 605 male parent	15	33	45.5
DFDM19010-13R	A8001	A8001 × 605 male parent	28	33	84.8
DFDM19011-CK	Lvyu 178	A8111 × B6211	29	33	87.9
DFDM19012-2	A8111	A8111 × B6211	31	33	93.9
DFDM19012-13	A8111	A8111 × B6211	21	33	63.6
DFDM19012-14	A8111	A8111 × B6211	30	33	90.9
DFDM19012-15	A8111	A8111 × B6211	31	33	93.9
DFDM19012-9	A8111	A8111 × B6275	22	33	66.7
DFDM19012-34	A8111	A8111 × PH4CV	29	33	87.9
DFDM19012-11	A8111	A8111 × 618 male parent	19	28	67.9
DFDM19013-2	YD9953 female parent	YD9953 female parent × B6211	24	33	72.7
DFDM19013-3	YD9953 female parent	YD9953 female parent × B6211	25	33	75.8
DFDM19013-8	YD9953 female parent	YD9953 female parent × B6211	25	33	75.8
DFDM19013-11	YD9953 female parent	YD9953 female parent × B6275	17	24	70.8
DFDM19013-1	YD9953 female parent	YD9953 female parent × PH4CV	29	33	87.9
DFDM19014-CK	Yufeng 303	303 female parent × PH4CV	30	33	90.9
DFDM19015-7	303 female parent	303 female parent × B6275	32	33	97.0
DFDM19016-CK	Zhongkeyu 505	505 female parent × PH4CV	29	33	87.9
DFDM19017-5	505 female parent	505 female parent × B6211	31	33	93.9
DFDM19017-8	505 female parent	505 female parent × B6232	26	33	78.8
DFDM19017-6	505 female parent	505 female parent × PH4CV	28	33	84.8
DFDM19017-15	505 female parent	505 female parent × PH4CV	29	33	87.9
DFDM19018-CK	Xianyu 335	PH6WC × PH4CV	30	33	90.9
DFDM19019-3	PH6WC	PH6WC × B6275	27	33	81.8
DFDM19019-4	PH6WC	PH6WC × PH4CV	29	33	87.9
DFDM19019-7	PH6WC	PH6WC × PH4CV	23	33	69.7
DFDM19019-8	PH6WC	PH6WC × PH4CV	29	33	87.9
DFDM19019-9	PH6WC	PH6WC × PH4CV	27	33	81.8
DFDM19019-11	PH6WC	PH6WC × PH4CV	28	33	84.8
DFDM19019-12	PH6WC	PH6WC × PH4CV	20	33	60.6
DFDM19019-13	PH6WC	PH6WC × PH4CV	32	33	97.0
DFDM19019-14	PH6WC	PH6WC × PH4CV	29	33	87.9

TABLE 2
GEBV ranking of 60 cross combinations
	Corresponding	GEBV
Cross combination	commercial hybrid	(g)
PH6WC × B6232		213.4
505 female parent × B6232		213.3
A8111 × B6232		212.9
PH6WC × PH4CV	Xianyu 335	211.5
505 female parent × PH4CV	Zhongkeyu 505	211.4
A8111 × PH4CV		211.0
303 female parent × B6232		209.9
A8001 × B6232		209.3
PH6WC × 605 male parent		208.8
505 female parent × 605 male parent		208.7
PH6WC × B6275		208.3
A8111 × 605 male parent		208.2
505 female parent × B6275		208.2
303 female parent × PH4CV	Yufeng 303	208.0
A8111 × B6275		207.7
A8001 × PH4CV		207.3
303 female parent × 605 male parent		205.3
303 female parent × B6275		204.8
A8001 × 605 male parent		204.6
A8001 × B6275		204.1
PH6WC × 618 male parent		203.7
505 female parent × 618 male parent		203.6
618 female parent × B6232		203.2
A8111 × 618 male parent		203.2
PH6WC × B6211		202.9
505 female parent × B6211		202.8
A8111 × B6211	Lvyu 178	202.4
605 female parent × B6232		202.0
618 female parent × PH4CV		201.2
YD9953 female parent × B6232		201.1
DK517 female parent × B6232		200.3
303 female parent × 618 male parent		200.2
605 female parent × PH4CV		200.1
A8001 × 618 male parent		199.5
303 female parent × B6211		199.4
YD9953 female parent × PH4CV		199.2
A8001 × B6211	Luyan 188	198.7
618 female parent × 605 male parent		198.5
DK517 female parent × PH4CV		198.3
618 female parent × B6275		198.0
605 female parent × 605 male parent	Denghai 605	197.3
605 female parent × B6275		196.8
YD9953 female parent × 605 male parent		196.5
YD9953 female parent × B6275		196.0
DK517 female parent × 605 male parent		195.6
DK517 female parent × B6275		195.1
A7016 × B6232		194.7
618 female parent × 618 male parent	Denghai 618	193.4
A7016 × PH4CV		192.8
618 female parent × B6211		192.6
605 female parent × 618 male parent		192.2
605 female parent × B6211		191.4
YD9953 female parent × 618 male parent		191.4
YD9953 female parent × B6211		190.6
DK517 female parent × 618 male parent		190.5
A7016 × 605 male parent		190.1
DK517 female parent × B6211		189.7
A7016 × B6275	Yayu No. 2	189.6
A7016 × 618 male parent		185.0
A7016 × B6211		184.2

Finally, it should be noted that the above descriptions are only preferred examples of the present disclosure and are not intended to limit the present disclosure. Although the present disclosure is described in detail with reference to the above examples, a person skilled in the art can still make modifications to the technical solutions described in the foregoing examples, or make equivalent replacement to some technical features. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A high-efficiency Zea mays L. breeding method based on an individual plant evaluation and a genome-wide selection (GWS), comprising the following steps: S 1. in a first cropping season, pollinating a Zea mays L. female parent with multiple male parents;S2. in a second cropping season, subjecting hybrid seeds to single-seed sowing, conducting an individual plant selection, and evaluating target traits;S3. identifying a parent of a selected cross combination;S4. subjecting a target trait of the selected cross combination to a genome-wide prediction;S5. selecting an excellent cross combination according to a predicted target trait; andS6. subjecting the excellent cross combination directly to a variety registration or to a further evaluation.

2. The high-efficiency Zea mays L. breeding method based on the individual plant evaluation and the GWS according to claim 1, wherein when the hybrid seeds are subjected to the single-seed sowing in S2, a female parent of the hybrid seeds subjected to the single-seed sowing is recorded.

3. The high-efficiency Zea mays L. breeding method based on the individual plant evaluation and the GWS according to claim 1, wherein during the single-seed sowing in S2, growth factors for individual plants are ensured to be consistent.

4. The high-efficiency Zea mays L. breeding method based on the individual plant evaluation and the GWS according to claim 1, wherein S3 specifically comprises the following steps: S31. screening genomic DNAs (gDNAs) of all male and female parents in the first cropping season to obtain molecular markers used to identify parental genotypes;S32. subjecting gDNA templates of all male and female parents in the first cropping season and the hybrid seeds to a polymerase chain reaction (PCR) amplification with the molecular markers, and recording genotypes;S33. deriving all possible cross combination genotypes according to the genotypes of all male and female parents in the first cropping season; andS34. comparing genotypes of the hybrid seeds with all possible cross combination genotypes derived, and recording a matching rate of identical genotype loci, wherein if the selected cross combination and a derived cross combination have a highest matching rate of identical genotype loci, a parent of the derived cross combination is a parent of the selected cross combination.

5. The high-efficiency Zea mays L. breeding method based on the individual plant evaluation and the GWS according to claim 1, wherein S4 specifically comprises the following steps: S41. genotyping the parent of the selected cross combination identified in S3, and inferring a genotype of the selected cross combination according to a genotype of the parent;S42. using target trait averages and genotypes of cross combinations evaluated in S2 to fit a genome-wide prediction model; andS43. predicting target traits of all possible cross combinations according to the genome-wide prediction model.