CN116831024A - Method for improving corn yield and quality through reducing optimal densification and capacity expansion and increasing rate - Google Patents

Abstract

The invention discloses a method for improving corn yield and quality by reducing the quality, increasing density, and expanding the volume and rate. The hybrid advantages of selected plant height and ear position height are reduced, the planting density of hybrids is increased, and the ear grain bulk weight and seed emergence rate are increased. Hybrid combinations are used to achieve dense planting, multi-resistance, and synergistic improvement in yield and quality of corn. This method conducts density tolerance tests on parental inbred lines to screen for stable panicle rows that have good green-keeping properties, strong lodging resistance, low shade avoidance response, high test weight, seed emergence rate and yield under high-density conditions. The stable genetic parent materials were combined into hybrid combinations to screen for short plant height, low ear position, early maturity, no empty stalks, resistance to lodging, good greenness, high grain bulk density, high ear seed yield and High yielding hybrid combination. By repeatedly comparing the selected combinations with the main recommended varieties in multiple ecological zones and production, the hybrid combinations with small variability at each test point are screened for approval.

Description

Methods to improve corn yield and quality by reducing optimal density, increasing volume and increasing rate

Technical field

The invention belongs to the technical field of corn breeding, and specifically relates to a method for reducing hybrid vigor of plant height and ear height, increasing planting density, grain bulk weight and ear emergence rate, thereby improving the yield and quality of corn varieties.

Background technique

Corn is my country's largest food crop. As my country's population increases, farmland resources shrink, the demand for corn continues to expand, and the competition for land between soybeans and corn becomes increasingly severe. Continuously increasing corn yields is an urgent problem for breeders to solve. The key to producing enough grain on a limited land area to ensure food security is to increase yields. Close planting is an important agronomic measure to increase corn yield, and breeding corn varieties suitable for high-density planting is the key. Varieties with high hybrid vigor have tall plants and luxuriant and flat leaves. When planted at high density, the colonies are prone to lodging, resulting in shading and severe shade-avoidance reactions in the plants. Therefore, varieties with high hybrid vigor are not necessarily suitable for high-yielding dense planting cultivation. Reducing the hybrid vigor of corn, increasing planting density, and increasing the number of ears harvested per unit area are effective ways to increase corn yield.

High yield is the main goal of corn breeding. Appropriately increasing planting density and expanding cultivation groups can increase biological yield and leaf area index and maintain high levels of photosynthetic rate, chlorophyll content and light transmittance, thereby achieving the goal of continuing to increase yields through dense planting. . At present, the density of most approved varieties in my country is 4,500-5,000 plants/acre. Breeding of density-tolerant varieties is an internal factor to increase planting density. In the past 50 years, the yield of corn hybrids per plant in the United States has not increased. The planting density has increased from 3500-4500 plants/acre to 5500 plants/acre. One of the main reasons for the increase in yield is the increase in planting density. With the construction of high-standard fertile fields and the improvement of cultivation technology in my country, breeding high-yield and density-tolerant new varieties and increasing corn planting density have become an inevitable trend in corn breeding. However, in actual production, increasing density intensifies the competition between plants for light, heat and nutrient resources. The empty stalk rate, seed setting rate, grain weight, lodging resistance, permeability and light energy utilization are reduced, ultimately leading to smaller fruit ears and lower yields. The improvement of corn yield level not only depends on the effective number of ears harvested per unit area, but also requires an increase in the number of ears and grain weight. Under dense planting conditions, fruit ears become smaller and the number of kernels per ear decreases, which can be compensated by an increase in kernel weight. Grain weight is one of the three components of corn yield and is crucial to improving corn yield. The key factors affecting grain weight are grain test weight and seed emergence rate.

Contents of the invention

The technical problem to be solved by the present invention is that there are few corn varieties suitable for close planting cultivation in production, and it is difficult to achieve high-density resource utilization and high quality of varieties such as high stalk ratio, low lodging resistance, poor firmness, and low yield during close planting cultivation. High-yield and mechanized harvesting provide a way to improve corn yield and quality through "reducing quality and increasing density" and "expanding capacity and increasing rate", and provide theoretical and technical support for the selection and breeding of high-quality and high-yielding corn varieties with efficient resource utilization under dense planting conditions.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

A method for improving the yield and quality of corn by reducing the quality, increasing the density, and expanding the volume and rate. The method is a breeding process of corn varieties with low hybrid vigor, tolerance to dense planting, high test weight, high seed rate, and high yield. The method is to select plant height The hybrid combination with high ear position reduces the hybrid vigor, increases the planting density of hybrids, and increases the ear grain weight and seed emergence rate, thereby achieving a synergistic improvement in corn density, multi-resistance, yield and quality. By conducting density tolerance tests on the parent inbred lines, stable panicle rows with good green staying power, strong lodging resistance, low shade avoidance reaction, high test weight, seed emergence rate and yield under high density conditions were screened. The stable genetic parent materials were combined into hybrid combinations to screen for short plant height, low ear position, early maturity, no empty stalks, resistance to lodging, good greenness, high grain bulk density, high ear seed yield and High yielding hybrid combination. By repeatedly comparing the selected combinations with the main recommended varieties in multiple ecological zones and production, the hybrid combinations with small variability at each test point are screened for approval. Specifically include:

(1) Selection of parents

The basic material female parent group and male parent group were selected and bred under the adverse ecological environment of light, hot water and fertilizer created at high density, and the parent plants were screened out to have low height, weak shade avoidance response, resistance to lodging, no empty culms, good fruiting, and The male and female parents with strong resistance to biotic and abiotic stresses have stable panicle rows;

(2) Breeding for “expansion and rate” of both parents

The dense-tolerant and stable panicle rows of both parents selected in (1) were bred again under the same high-density conditions, and the stable genetics of the male and female parents with high grain bulk weight and seed emergence rate were selected. ear rows and cross them to form a hybrid combination;

(3) High-yielding and high-quality breeding of hybrid combinations by “reducing quality and increasing density”

The combined hybrid combinations in (2) were identified in multiple ecological zones under high-density conditions, and the results showed that the hybrid vigor of plant height was reduced, the hybrid vigor of ear height was reduced, the empty stalk rate was reduced, the comprehensive stress resistance was strong, and the grain bulk density was reduced. , a hybrid combination with improved seed yield and yield per panicle.

Furthermore, during parent breeding, the basic material female parent group and male parent group were selected under the adverse ecological environment of light, hot water and fertilizer created at a high density of 7500 plants/acre.

Furthermore, re-selection under the same high-density conditions in (2) refers to high-density planting under the same conditions as in (1).

Further, in (2), the bulk density of the ear when the grain moisture content is 14% during natural pollination, and the dry ear seed emergence rate when the grain moisture content is less than 20% after threshing, the male parent grain bulk density is above 780g/L and dry. The self-crossed ear rows corresponding to the ear rows with a seed yield rate of more than 90% will be reserved. After the seeding test, the self-crossed ear rows corresponding to the female parent grain bulk density will be above 780g/L and/or the dry ear seed yield rate will be above 90%. Leave seeds in the ears.

Furthermore, the combined hybrid combinations were used for multi-ecological zone identification under high-density conditions of 6,500 plants/acre.

Furthermore, (3) the hybrid vigor of medium plant height is reduced by 8-16%, and the hybrid vigor of high panicle position is reduced by 8-22%.

Furthermore, the hybrid combination achieved in (3) has a plant height of 220-265cm, an ear height of 90-100cm, an ear rate of 99-100%, a bulk density of 790-800g/L, and a seed yield of 90-92%. .

Beneficial effects of the present invention: agronomic traits such as plant height and ear position height are key indicators that affect dense planting of corn. By "reducing quality and increasing density", the hybrid vigor of plant height and ear position height is reduced to increase planting density and ensure ear growth under dense planting conditions. rate and firmness; at the same time, through "expansion rate", the test weight and seed yield rate are increased, and the harvested grain weight is increased. The increase in the number of ears per mu, number of grains per ear and grain weight will play a better and maximum role in increasing yield and achieve high yield and high quality under high density conditions. The implementation of this patent will help breeders improve breeding theories, breeding materials and breeding methods.

Description of the drawings

Figure 1 shows the yield comparison of MY73 and Zhengdan 958 at different densities.

Figure 2 Comparison of yields of Yudan 8008 and Xianyu 335 at different densities.

Figure 3 Comparison of yields of Yudan 883 and Denghai 605 at different densities.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that the following examples are only used to illustrate the present invention but not to limit the scope of the present invention. Those skilled in the field can make some non-essential improvements and adjustments based on the contents of the above invention.

The invention provides a method for improving the yield and quality of corn by reducing the quality, increasing the density and increasing the volume and increasing the rate. The method is a breeding process of corn varieties with low hybrid vigor, tolerance to dense planting, high test weight, high seed rate and high yield. Breeding a hybrid combination that reduces hybrid vigor for plant height and ear height, increases hybrid planting density, and increases ear grain bulk weight and seed emergence rate, thereby achieving a coordinated increase in corn density, multi-resistance, and yield and quality. By conducting density tolerance tests on the parent inbred lines, stable panicle rows with good green staying power, strong lodging resistance, low shade avoidance reaction, high test weight, seed emergence rate and yield under high density conditions were screened. The stable genetic parent materials were combined into hybrid combinations to screen for short plant height, low ear position, early maturity, no empty stalks, resistance to lodging, good greenness, high grain bulk density, high ear seed yield and High yielding hybrid combination. By repeatedly comparing the selected combinations with the main recommended varieties in multiple ecological zones and production, the hybrid combinations with small variability at each test point are screened for approval. Specifically include:

(1) Selection of parents

The basic material female parent group and male parent group were selected and bred under the adverse ecological environment of light, hot water and fertilizer created at high density, and the parent plants were screened out to have low height, weak shade avoidance response, resistance to lodging, no empty culms, good fruiting, and The male and female parents with strong resistance to biotic and abiotic stresses have stable panicle rows;

(2) Breeding for “expansion and rate” of both parents

The dense-tolerant and stable panicle rows of both parents selected in (1) were bred again under the same high-density conditions, and the stable genetics of the male and female parents with high grain bulk weight and seed emergence rate were selected. ear rows and cross them to form a hybrid combination;

(3) High-yielding and high-quality breeding of hybrid combinations by “reducing quality and increasing density”

The combined hybrid combinations in (2) were identified in multiple ecological zones under high-density conditions, and the results showed that the hybrid vigor of plant height was reduced, the hybrid vigor of ear height was reduced, the empty stalk rate was reduced, the comprehensive stress resistance was strong, and the grain bulk density was reduced. , a hybrid combination with improved seed yield and yield per panicle.

Furthermore, during parent breeding, the basic material female parent group and male parent group were selected under the adverse ecological environment of light, hot water and fertilizer created at a high density of 7500 plants/acre.

Furthermore, re-selection under the same high-density conditions in (2) refers to high-density planting under the same conditions as in (1).

Further, in (2), the bulk density of the ear when the grain moisture content is 14% during natural pollination, and the dry ear seed emergence rate when the grain moisture content is less than 20% after threshing, the male parent grain bulk density is above 780g/L and dry. The self-crossed ear rows corresponding to the ear rows with a seed yield rate of more than 90% will be reserved. After the seeding test, the self-crossed ear rows corresponding to the female parent grain bulk density will be above 780g/L and/or the dry ear seed yield rate will be above 90%. Leave seeds in the ears.

Furthermore, the combined hybrid combinations were used for multi-ecological zone identification under high-density conditions of 6,500 plants/acre.

Furthermore, (3) the hybrid vigor of medium plant height is reduced by 8-16%, and the hybrid vigor of high panicle position is reduced by 8-22%.

Furthermore, the hybrid combination achieved in (3) has a plant height of 220-265cm, an ear height of 90-100cm, an ear rate of 99-100%, a bulk density of 790-800g/L, and a seed yield of 90-92%. .

Example 1 Breeding of density-tolerant, high-yielding and high-quality corn variety MY73

This embodiment provides a breeding process for the corn variety MY73 with low hybrid vigor, tolerance to dense planting, high test weight, high seed rate, and high yield. The steps are as follows:

1. Breeding of MY73 parents

The inbred line materials collected and created by the corn breeding team of Henan Agricultural University were identified as female parent material group and male parent material group according to the germplasm source. Through years of breeding selection, it was found that the suitable planting density of these materials for stable ear rows is generally 4500-5000. Plants/acre. The high competitive pressure of resources such as light, hot water and fertilizer created by high density can further screen the various characteristics of inbred materials. These materials were planted in double rows with 4m long rows. Double seeds were sown in each hole. One strong seedling was left when the leaves were 4. The planting density was 7500 plants/acre, that is, they were screened under high density pressure and pollinated during pollination. Half of each panicle row is self-pollinated for later screening and seed retention, and the other half is naturally pollinated for fruitfulness observation. After fertilization, the plant height, empty stalk rate, and seed setting rate were measured. When the milk line was halfway, the greenness and lodging resistance were measured. It was found that the performance of most materials in shade avoidance response, lodging resistance, empty stalk rate, firmness and other abiotic stress disasters and performance under suitable density differ greatly. Materials with strong competitiveness under high-density pressure may produce hybrid combinations with higher and more stable yields. Therefore, the inbred line materials of each parent were screened under high-density conditions of 7,500 plants/acre. The selected plant height is low under normal density conditions, and there is almost no shade avoidance reaction at high density; there is no difference in lodging resistance under high density and normal density conditions, both are strong, showing hard stems and strong ability to stand in the later period. The aerial roots are well developed; under high-density conditions, the plants all have fruit ears without empty stalks, and the fruit ears have good firmness during natural pollination; in addition, when planted at high density, the plants have strong disease resistance in the later stages, as shown by the good leaves that stay green. The self-crossed ears of the male and female parents were harvested and planted, and the corresponding naturally pollinated ears were harvested and tested indoors.

2. Breeding for "expansion and rate increase" of both parents

The selected panicle rows for indoor seed testing were screened again based on their grain bulk weight and seed emergence rate during natural pollination. The bulk density of the ear when the grain moisture content was 14% during natural pollination, and the seed emergence rate of the dry ear (the grain moisture content after threshing was less than 20%) were investigated respectively. Seeds should be reserved for the self-crossed ears corresponding to the ear rows with a male parent grain bulk density above 780g/L and a dry ear seed yield rate above 90%. After the seeding test, the grain bulk density of the female parent is above 780g/L and the dry fruit ear seeding rate is above 90%, or the female parent only has a grain bulk density above 780g/L, or the female parent only has dry fruit panicles with a seeding rate above 90%. Leave seeds in corresponding rows of selfed ears.

3. High-yielding and high-quality breeding of hybrid combinations by “reducing quality and increasing density”

The selected self-crossed fruit ears of the above-mentioned male and female parents are replanted into ear rows, and the male parent is pollinated with each female parent respectively to prepare a hybrid combination. Using the main production variety Zhengdan 958 as a control, the obtained hybrid combination was identified in multiple ecological zones in Zhumadian Xiping, Shangqiu Yongcheng, Zhengzhou and Xuchang. According to the measurement results of plant height and ear height after fertilization, the plant height range is 220-230cm and the ear height range is 90-95cm. According to the hybrid vigor index, select a hybrid combination with 15-25% lower hybrid vigor for plant height and ear position than Zhengdan 958. When the grain milk line is half way, the empty stalk rate and leaf greenness of these hybrid combinations were investigated. After harvest, the seed emergence rate, grain bulk weight and yield of dry fruit ears were measured. The empty stalk rate was significantly lower than that of Zhengdan 958 or had no empty stalks. The stalk and grain bulk density are 790-800g/L, the seed emergence rate is 90-92%, and the yield is more than 8% higher than that of Zhengdan 958.

Based on the above screening, it was found that the hybrid combination MY73 of the female inbred line T1932 and the male inbred line T856 has a plant height of 230cm and an ear height of 94cm. The hybrid vigor of MY73 for plant height and ear height is 15.2 lower than that of Zhengdan 958 respectively. % and 10.7%. The grain bulk density is 798g/L, the seed emergence rate is 92%, and the yield is 9.7% higher than that of Zhengdan 958 (Table 1). In the multi-point density test in the Huanghuaihai summer sowing area in 2022, the yield was the highest when the sowing density of MY73 acres was 6,500 plants, which was 2,000 more plants than the variety Zhengdan 958, which has a larger promotion area in production. Therefore, it is recommended that the density be suitable for promotion in this area. The number is 6,500 plants/acre (Figure 1).

Table 1 Comparison of hybrid vigor, grain test weight and ear emergence rate between corn variety MY73 and Zhengdan 958

Note: The hybrid vigor index refers to the ratio of the average value of a certain trait in hybrid F1 to the average value of the same trait in both parents. Expressed by the formula: hybrid vigor index (%) = F1/[(P1+P2)/2]×100%

Example 2 Breeding of Yudan 8008, a high-yield and high-quality corn variety with tolerance to density

The selection process of Yudan 8008 parents in this embodiment is similar to that of MY73 in Example 1. After selection, the paternal inbred line numbered T4691 and the female inbred line numbered T4953 were obtained. The hybrid combination of two parents has a plant height of 264cm and a panicle height of 100cm. Compared with Xianyu 335, the main popular variety in production, the hybrid vigor of Yudan 8008 in plant height and ear height was 8.0% and 9.6% lower than that of Xianyu 335, respectively. The grain bulk density is 791g/L, the seed emergence rate is 90%, and the yield is 10.3% higher than that of Xianyu 335 (Table 2). In the multi-point test in the Huanghuaihai summer sowing area in 2022, the sowing density per mu of Yudan 8008 increased by 2000-2500 plants compared with Xianyu 335, the main variety in production. It is recommended that the density suitable for promotion in this area is about 6500 plants/mu (Figure 2).

Table 2 Comparison of hybrid vigor, grain test weight and ear emergence rate between corn variety Yudan 8008 and Xianyu 335

Example 3 Breeding of Yudan 883, a high-yield and high-quality corn variety with tolerance to density

The breeding process of Yudan 883 parents in this embodiment is similar to that in Example 1 and Example 2. After selection, the male inbred line number G4849 and the female inbred line number T3875 are obtained. The hybrid combination of two parents has a plant height of 241.0cm and a panicle height of 91.5cm. Compared with Denghai 605, the main production variety, the hybrid vigor of Yudan 883 in terms of plant height and ear height was 8.9% and 21.3% lower than that of Denghai 605, respectively. The grain bulk density is 790g/L, the seed emergence rate is 91%, and the yield is 7.1% higher than that of Denghai 605 (Table 3). The sowing density per mu in the Huanghuaihai summer sowing area is 1500-2000 plants higher than that in Denghai 605. It is recommended that the density suitable for promotion in this area is 6000-6500 plants/mu (Figure 3).

Table 3 Comparison of hybrid vigor, grain test weight and ear emergence rate between corn variety Yudan 883 and Denghai 605

The basic principles and main features of the invention as well as the advantages of the invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have other aspects. Various changes and modifications are possible, which fall within the scope of the claimed invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims (10)

1. A method for improving the yield and quality of corns through reducing the quality and the density and the capacity and increasing the rate is characterized in that the method is a breeding process of low hybrid vigor, close planting resistance, high volume weight, high seed yield and high yield corn varieties, and specifically comprises the following steps:

(1) Parent breeding;

(2) Parent 'capacity expansion rate increase' breeding;

(3) Hybrid combination 'reduced quality densification' high yield and high quality breeding.

2. The method for improving the yield and the quality of corn by reducing the densification and the capacity expansion ratio according to claim 1, wherein the method comprises the following steps: the parent breeding process is as follows: the parent plant and the male parent plant are bred under the ecological environment of high-density photo-thermal water-fertilizer adversity stress, and the parent plant with low parent plant height, weak shade-avoidance reaction, lodging resistance, no empty stalk, good fruiting performance and strong biological and abiotic adversity resistance and the stable ear row of the parent plant are screened.

3. The method for improving corn yield and quality by reducing densification and capacity expansion and increase rate according to claim 1 or 2, characterized in that: during parent breeding, a basic material female parent group and a basic material male parent group are bred under ecological environment of photo-thermal water fertilizer adversity stress created by high density 7500 plants/mu.

4. The method for improving the yield and the quality of corn by reducing the densification and the capacity expansion ratio according to claim 1, wherein the method comprises the following steps: the parent 'expansion rate' breeding method comprises the following steps: and (3) breeding the parent density-resistant stable spike rows bred in the step (1) under the same high-density condition again, identifying and selecting the parent and female stable genetic spike rows with high male parent and female spike grain volume weights and seed yield, and hybridizing the parent and female stable spike rows to prepare a hybridization combination.

5. The method for improving corn yield and quality by reducing densification and capacity expansion ratio as claimed in claim 4, wherein: the second breeding under the same high-density condition refers to high-density planting under the same condition as the breeding of the parent in the step (1).

6. The method for improving corn yield and quality by reducing densification and capacity expansion ratio as claimed in claim 4, wherein: (2) The method comprises the steps of respectively investigating the volume weight of the seeds with 14% of water content of the seeds during natural pollination and the seed yield of the dried seeds with the water content of less than 20% after threshing, reserving seeds of the selfing seeds corresponding to the ear rows with the volume weight of the male parent seeds being 780g/L or more and the seed yield of the dried seeds being 90% or more, reserving seeds of the selfing seeds corresponding to the ear rows with the volume weight of the female parent seeds being 780g/L or more and/or the seed yield of the dried seeds being 90% or more after seed examination.

7. The method for improving the yield and the quality of corn by reducing the densification and the capacity expansion ratio according to claim 1, wherein the method comprises the following steps: the hybrid combined 'reduced-quality densification' high-yield and high-quality breeding method comprises the following steps: and (3) carrying out multi-ecological area identification on the combined hybridization combination in the step (2) under a high-density condition, and screening hybridization combinations with reduced plant height hybrid vigor, reduced spike position hybrid vigor, reduced empty stalk rate, strong comprehensive stress resistance and improved grain volume weight, single spike seed yield and yield.

8. The method for improving corn yield and quality by reducing densification and capacity expansion ratio according to claim 7, wherein: the multi-ecological area identification is carried out under the high density condition of 6500 plants/mu by the combined hybridization combination.

9. The method for improving corn yield and quality by reducing densification and capacity expansion ratio according to claim 1 or 7, characterized in that: (3) The hybrid vigor of the medium plant height is reduced by 8-16%, and the hybrid vigor of the spike height is reduced by 8-22%.

10. The method for improving corn yield and quality by reducing densification and capacity expansion ratio according to claim 1 or 7, characterized in that: (3) The plant height of the hybrid combination is 220-265cm, the spike height is 90-100cm, the spike forming rate is 99-100%, the volume weight is 790-800g/L, and the seed yield is 90-92%.