Breeding method for improving comprehensive disease resistance of corn

Abstract

The invention provides a breeding method for improving comprehensive disease resistance of corn, which comprises the following steps of: hybridizing stem rot resistant corn and rough dwarf disease resistant corn as parents to harvest grains, and selecting the grains with stem rot resistance and rough dwarf disease resistance from the grains as first-generation grains; after the first-generation seeds are selfed for one generation, second-generation seeds are harvested; taking the second-generation grains and northern leaf blight-resistant corn as parents, carrying out hybridization to harvest grains, and selecting grains with stem rot resistance, rough dwarf disease resistance and northern leaf blight resistance from the grains as third-generation grains; the third-generation seeds are subjected to selfing for one to two generations and are subjected to backcrossing for two to three generations, and the seeds with stable stem rot resistance, rough dwarf disease resistance and northern leaf blight resistance characters are harvested. The seeds capable of resisting stem rot, rough dwarf disease and northern leaf blight are obtained at the same time through the breeding method and have good comprehensive disease resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of corn breeding, and particularly relates to a breeding method for improving the comprehensive disease resistance of corn. Background Art

[0002] At present, corn is widely planted in northern my country as an economic crop. However, corn has many diseases, which affect its yield. Moreover, corn has a single disease resistance. Currently, many corn seeds are only resistant to one disease, and there is a lack of corn germplasm resources with comprehensive disease resistance. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a breeding method for improving the comprehensive disease resistance of corn in response to the above-mentioned deficiencies in the existing technology. The grains harvested by this method can be resistant to stalk rot, rough dwarf disease and large leaf spot at the same time, and have good comprehensive disease resistance.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is: a breeding method for improving the comprehensive disease resistance of corn, characterized by comprising:

[0005] Using corn resistant to stalk rot and corn resistant to rough dwarf disease as parents, hybridizing and harvesting grains, and selecting grains resistant to both stalk rot and rough dwarf disease from the grains as first-generation grains;

[0006] After the first generation of kernels are self-pollinated for one generation, the second generation of kernels are harvested;

[0007] The second generation of kernels and corn resistant to northern leaf blight are used as parents, and kernels are harvested by hybridization. Kernels resistant to stalk rot, rough dwarf disease, and northern leaf blight are selected from the kernels as the third generation of kernels.

[0008] The third generation of grains are self-pollinated for one to two generations and backcrossed for two to three generations, and grains with stable resistance to stem rot, rough stunt and large leaf spot are harvested.

[0009] Preferably, the stalk rot-resistant corn is the highly resistant corn stalk rot inbred line 1145 or the disease-resistant inbred line LA076.

[0010] Preferably, the rough dwarf disease-resistant corn is the rough dwarf disease-resistant corn inbred line X178.

[0011] Preferably, the corn resistant to northern leaf spot disease is transgenic corn having the corn disease resistance gene MR6.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. The present invention uses stalk rot-resistant corn and rough dwarf disease-resistant corn as parents to obtain grains resistant to stalk rot and rough dwarf disease, and then self-pollinates for one generation and hybridizes with large leaf spot resistant corn as a parent to obtain grains resistant to stalk rot, rough dwarf disease and large leaf spot. Finally, self-pollinates for one to two generations and backcrosses for two to three generations to harvest grains with stable resistance to stalk rot, rough dwarf disease and large leaf spot. The harvested grains are resistant to stalk rot, rough dwarf disease and large leaf spot at the same time and have good comprehensive disease resistance.

[0014] The technical solution of the present invention is further described in detail below through examples.

[0015] Description of Reference Numerals

[0016] Figure 1 This is the field planting test site in Example 1 of the present invention.

[0017] Figure 2 This is the greenhouse planting test site in Example 1 of the present invention.

[0018] Figure 3 This is a photo of a corn plant showing the fourth generation of kernels grown in Example 1 of the present invention.

[0019] Figure 4 This is a photo of a corn plant with fifth-generation kernels grown in Example 1 of the present invention. DETAILED DESCRIPTION

[0020] Example 1

[0021] A breeding method for improving comprehensive disease resistance of corn according to an embodiment of the present invention comprises:

[0022] Using corn resistant to stalk rot and corn resistant to rough dwarf disease as parents, hybridizing and harvesting grains, and selecting grains resistant to both stalk rot and rough dwarf disease from the grains as first-generation grains;

[0023] After the first generation of kernels are self-pollinated for one generation, the second generation of kernels are harvested;

[0024] The second generation of kernels and corn resistant to northern leaf blight are used as parents, and kernels are harvested by hybridization. Kernels resistant to stalk rot, rough dwarf disease, and northern leaf blight are selected from the kernels as the third generation of kernels.

[0025] The third generation of grains were self-pollinated for one generation and backcrossed for two generations, and grains with stable resistance to stem rot, rough dwarf disease and large leaf spot were harvested.

[0026] In this embodiment, the stalk rot-resistant corn is the inbred line 1145 with high resistance to corn stalk rot. The molecular marker SSR334 for assisting in screening stalk rot-resistant corn disclosed in authorization announcement number CN 102395678 B is used to assist in screening stalk rot-resistant kernels from the first generation of kernels.

[0027] The rough dwarf disease-resistant corn is the rough dwarf disease-resistant corn inbred line X178. Molecular markers closely linked to the major QTL for rough dwarf disease resistance disclosed in Grant Publication No. CN 105349684B can assist in screening stalk rot-resistant kernels from first-generation kernels.

[0028] The corn resistant to northern leaf blight is transgenic corn with the corn transgene MR6. The transgenic corn is obtained from corn seeds by the method disclosed in the authorization announcement number CN 103352039 B, as disclosed therein, using the Agrobacterium-mediated method to introduce pTE102-MR into the corn inbred line H99, and using quantitative PCR technology to detect the slight expression level of MR6 in the grains, thereby screening grains resistant to northern leaf blight.

[0029] By simultaneously using the molecular marker SSR334 for stalk rot resistance and a marker tightly linked to the major QTL for maize rough dwarf resistance, first-generation kernels can be screened for resistance to both stalk rot and stalk rot. By simultaneously using the molecular marker SSR334 for stalk rot resistance and a marker tightly linked to the major QTL for maize rough dwarf resistance, and by detecting the expression level of MR6 in kernels, kernels can be screened for resistance to stalk rot, rough dwarf, and large leaf spot.

[0030] In this embodiment, the experimental farm of Hebei North University in Zhangjiakou was selected as Figure 1 Sowing is carried out by first sowing the prepared seeds of the inbred line 1145 with high resistance to corn stalk rot and the seeds of the inbred line X178 with resistance to corn rough dwarf disease as parents in late April. The hybrid is then crossed and the grains are harvested in mid-to-late September. Through molecular marker-assisted breeding, the grains with both stalk rot and rough dwarf disease resistance are selected from the grains based on the molecular marker SSR334 for corn stalk rot resistance and a molecular marker closely linked to the major effect QTL for corn rough dwarf disease resistance as the first generation of grains. At the same time, grains with good plant shape, plant height, and ear shape are selected as much as possible.

[0031] The first generation of grains were planted in the greenhouse in October. Figure 2 As shown, after one generation of self-pollination after flowering, the second generation of grains were harvested in March of the following year to screen grains with stable resistance to stem rot and rough dwarf disease.

[0032] Next, the second-generation kernels and transgenic maize seeds carrying the maize transgene MR6 were sown in the field as parents, hybridized, and the kernels were harvested. The expression of MR6 in the kernels was detected using the molecular marker SSR334 for maize resistance to stalk rot and a molecular marker closely linked to the major QTL for maize resistance to rough dwarf disease. Kernels with resistance to stalk rot, rough dwarf disease, and large leaf spot were selected as the third-generation kernels.

[0033] Finally, the third generation of grains were planted in the greenhouse for another generation, and after flowering, they were self-pollinated for one generation to obtain the fourth generation of grains. Then, the field and greenhouse were backcrossed for two generations. The fourth and fifth generation grains planted were as follows: Figure 3 and 4 As shown, the grains with stable resistance to stem rot, rough dwarf disease and large leaf spot were screened and harvested as the sixth generation grains.

[0034] Table 1 Agronomic traits of grains of each generation

[0035]

[0036] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A breeding method for improving comprehensive disease resistance of corn, characterized in that: include: Using corn resistant to stalk rot and corn resistant to rough dwarf disease as parents, hybridizing and harvesting grains, and selecting grains resistant to both stalk rot and rough dwarf disease from the grains as first-generation grains; After the first generation of kernels are self-pollinated for one generation, the second generation of kernels are harvested; The second generation of kernels and corn resistant to northern leaf blight are used as parents, and kernels are harvested by hybridization, and kernels resistant to stem rot, rough dwarf disease and northern leaf blight are selected from the kernels as the third generation of kernels; The third generation of grains are self-pollinated for one to two generations and backcrossed for two to three generations, and grains with stable resistance to stem rot, rough dwarf disease and large leaf spot disease are harvested.

2. The breeding method for improving comprehensive disease resistance of corn according to claim 1, characterized in that: The stalk rot-resistant corn is the inbred line 1145 with high resistance to corn stalk rot.

3. The breeding method for improving comprehensive disease resistance of corn according to claim 1, characterized in that: The rough dwarf disease resistant corn is the rough dwarf disease resistant corn inbred line X178.

4. The breeding method for improving comprehensive disease resistance of corn according to claim 3, characterized in that: The corn resistant to northern leaf spot disease is transgenic corn having the corn disease resistance gene MR6.

Images