2. Variety name: Zhongnongda 678;

3. Applicant: China Agricultural University;

4. Breeder: China Agricultural University;

5. Variety source: c229×C783；; ;

6. Characteristics: The emergence to maturity of middle-late maturing spring maize population in East China and North China is 128.5 days, which is 0.5 days earlier than the control Zheng Dan 958. Compact plant type, plant height 269 cm, spike height 1 10 cm, spike length 19.2 cm, rows per spike 14~ 18 rows, and 100 grains weight 39.3 grams. Inoculation identification showed that it was resistant to stem rot, moderately resistant to ear rot, susceptible to leaf spot, head smut and gray leaf spot. Quality analysis showed that the grain bulk density was 764g/L, crude protein content was 65438 00.54%, crude fat content was 3.58%, crude starch content was 76.74%, and lysine content was 0.28%. The emergence to maturity of summer maize population in Huanghuaihai was 102 days, which was 0.5 days earlier than that of control Zheng Dan 958. Seedling leaf sheath is purple, leaf is green, leaf margin is purple, anther is purple, glume is green. The plant type is compact, the plant height is 256 cm, the ear position is 97 cm, and the number of leaves is 20. The ear is tubular, the ear length is 17.3cm, the rows per ear are 12~ 18, the ear axis is red, the seeds are yellow and dentate, and the 100-grain weight is 34.85g g. Inoculation identification shows that it is resistant to stem rot, moderately resistant to leaf spot, Curvularia leaf spot, southern rust and highly susceptible to ear rot. Quality analysis showed that the grain bulk density was 760g/L, crude protein content was 65438 00.06%, crude fat content was 3.765438 0%, crude starch content was 76.25%, and lysine content was 0.28%.

7. Yield performance: From July, 2065438 to July, 20 18, I participated in the regional test of middle and late-maturing spring corn groups in East China and North China, and the average yield per mu for two years was 76 1.3 kg, which was 5.8% higher than that of the control Zheng Dan 958. The production test in 20 18 years showed that the average yield per mu was 732.5 kg, which was 5.0% higher than that of the control Zheng Dan 958. During 20 17-20 18, we participated in the regional test of Huanghuaihai Summer Maize Group, and the average yield per mu for two years was 654.2kg, which was 5.3% higher than that of the control Zheng Dan 958. The production test in 20 18 years showed that the average yield per mu was 607.3kg, which was 8.6% higher than that of the control Zheng Dan 958.

8. Key points of cultivation techniques: Sow in middle and late-maturing spring corn areas in East China and North China from late April to early May; The planting density is 4500 plants per mu; Planting in plots with medium or high fertility; Pay attention to the control of leaf spot and corn borer in the later stage. Sowing in the middle and late June in the yellow summer corn area; The planting density is 4500 plants per mu; Planting in plots with medium or high fertility; Pay attention to the prevention and control of ear rot and smut.

9. Appraisal opinion: This variety conforms to the national maize variety appraisal standard and has passed the appraisal. It is suitable for most areas of Siping City, Songyuan City and Changchun City in Jilin Province, Liaoyuan City and Baicheng City, some areas of Jilin City, southern Tonghua City, most areas of Liaoning Province except the eastern mountainous areas and Dalian and donggang city, most areas of Chifeng City and Tongliao City in Inner Mongolia, Xinzhou City, Jinzhong City, Taiyuan City, Yangquan City, Changzhi City, Jincheng City and Pingchuan District of Lvliang City in Inner Mongolia. It is also suitable for planting in southern and southern areas of Henan Province, Shandong Province, Baoding City and Cangzhou City of Hebei Province, Guanzhong Irrigation District of Shaanxi Province, Yuncheng City and Linfen City of Shanxi Province, some Pingchuan areas of Jincheng City, areas north of Huaihe River in Jiangsu Province and Anhui Province, and Xiangyang area of Hubei Province.