Breeding of Jingdan 15, a New Stress-resistant and High-yield Maize Cultivar

Jimei HUANG, Dinghua ZHANG, Xiaohong TIAN, Chunxiu XU, Mei YANG, Chengcai HUANG

1. Qujing Experimental Station of National Maize Industrial Technology System/Qujing Academy of Agricultural Sciences, Qujing 655000, China; 2. Yunnan Zhujiang Seed Industry Co., Ltd., Qujing 655331, China

Abstract The parental origin, breeding process, yield, traits and characters, and cultivation and seed production key points of Jingdan 15, a stress-resistant and high-yield maize cultivar are introduced, in order to provide reference and help for maize breeders, agricultural extension personnel and grain farmers.

Key words Maize, Jingdan 15, Breeding

1 Introduction

Jingdan 15 is a high-quality single cross maize cultivar bred by Huang Jimei, a researcher of Qujing Academy of Agricultural Sciences, in 2013 with QJ12-3 as female parent and QJ12-1 as male parent. In 2017-2018, it participated in the regional test, and in 2018, it participated in the production test of spring maize of Sichuan Agricultural University. It was approved by the National Crop Variety Approval Committee of the Ministry of Agriculture, China in November, 2020, and the approval number is Guo Shen Yu 20200410. It is suitable for the hilly, flat and low mountain areas of Sichuan Province, Chongqing Municipality, Hunan Province, Hubei Province and Shaanxi Province with an altitude of 800 m and below, the areas of Guiyang City, Qiannan Prefecture, Qiandongnan Prefecture, Tongren City and Zunyi City of Guizhou Province with altitude below 1 100 m, the hilly, flat and low mountain areas of Kunming, Chuxiong, Yuxi, Dali and Qujing, as well as the areas of Wenshan, Honghe, Puer, Lincang, Baoshan, Xishuangbanna and Dehong with an altitude of 800-1 800 m in Yunnan Province, and Guilin City and Hezhou City of Guangxi Zhuang Autonomous Region. The cultivar is widely adaptable, resistant to stress and diseases, and high in yield, and is favored by grain farmers.

2 Parental origin and breeding process

2.1 Parental origin

Taking QJ0803 (S) bred by crossing hybrid Xianyu 696 (♀) and inbred line Shui1-6 (

♂

) in 2008 as the basic material, the female parent QJ12-3 was bred by bagging for 4 years and 8 generations. It became a stable line in 2012. The pedigree is QJ0803 (S)-1-2-1-2-1-2-1, named QJ12-3. The male parent QJ12-1 was bred by bagging for 4 years and 8 generations using QJ0801 (S) as the basic material, which was crossed with hybrid Xuanhuangdan 4 as the female parent and Ludan 8 as the male parent in 2008. The line became stable in 2012, with pedigree of QJ0801 (S)-1-2-1-1-2-1-1, named QJ12-1.

2.2 Breeding process

Jingdan 15 was bred in 2013. It participated in the identification and screening test in the experimental base of Qujing Academy of Agricultural Sciences in 2014, the multi-pilot comparative test in Baoshan, Qujing, Xuanwei, Huize, Wenshan, Dehong, Lincang, Chuxiong, Shizong and Ludian of Yunnan Province in 2015 and 2016, the regional test of spring maize of Sichuan Agricultural University in 2017-2018, and the production test of spring maize of Sichuan Agricultural University in 2018. The results show that the cultivar had good disease resistance, strong stress resistance, wide adaptability and excellent quality. It was approved by the National Crop Variety Approval Committee of the Ministry of Agriculture, China in November, 2020.

3 Yield

3.1 Regional tests

The cultivar participated in the regional test of spring maize in southwestern China in 2017-2018. In 2017, the average yield of Jingdan 15 was 9 660.00 kg/ha, increased by 19.8% compared with that of Yudan 8 (control) (

P

<0.01). The proportion of pilots with yield improved reached 84.4%, ranking second among the tested varieties. In 2018, the average yield of Jingdan 15 was 9 337.50 kg/ha, increased by 13.78% compared with that of Yudan 8 (control) (

P

<0.01). The proportion of pilots with yield improved reached 84.62%, ranking fifth among the tested varieties. The average yield of Jingdan 15 in the two years was 9 498.75 kg/ha, 16.76% higher than that of Yudan 8 (control).

3.2 Production test

Jingdan 15 participated in the production test of spring maize in southwestern China in 2018. The average yield was 9 180.00 kg/ha, increased by 17.65% compared with that of Yudan 8 (control) (

P

<0.01). The proportion of pilots with yield improved reached 84.62%, ranking fourth among the tested varieties.

3.3 Production demonstration

In 2019, Jingdan 15 was planted demonstratively in Taguanying Village, Zhaokua Town, Luliang County, Yunnan Province, with an area of 67.73 ha. The average yield was 11 244.6 kg/ha, increased by 33.65% compared to that of Zhongyu 335 (control). In 2020, Jingdan 15 participated in the demonstrative cultivation (6.67 ha) in Baishapo Village, Lingjiao Township, Zhanyi District, Qujing City, Yunnan Province, and showed am average yield of 13 654.5 kg/ha, 18.53% higher than that of Zhongyu 335 (control). In the areas with different altitudes, Jingdan 15 all performed outstandingly. In 2019 and 2020 with severe drought, Jingdan 15 still exerted good yield without irrigation in the whole growth period, suggesting that it is drought and barren-tolerant. Therefore, it is favored by farmers in mountainous areas.

4 Traits and characters

4.1 Agronomic traits

It took 122.7 d from seedling emergence to maturity, 2.5 d longer than Yudan 8 (control). In young seedlings, the leaf sheaths are light purple, the leaves are green, the leaf margin is green, the anthers are yellow, and the glumes are light purple. The plant type is semi compact, with plant height of 304.4 cm, ear height of 115.45 cm and 17 leaves in adult plant. The ears are cylindrical, with a length of 18.6 cm, row number per ear of 16-18, ear diameter of 5 cm, corncobs white, kernels yellow and semidentate, and hundred-seed weight of 35.2 g.

4.2 Quality analysis

Jingdan 15 was tested by Grain Quality Inspection and Testing Center of Ministry of Agriculture and Rural Areas, China, with grain bulk density of 776 g/L, crude protein content of 10.35%, crude fat content of 4.52%, crude starch content of 72.08% and lysine content of 0.35%.

4.3 Resistance identification

After two consecutive years of inoculation identification of Institute of Plant Protection, Sichuan Academy of Agricultural Sciences and College of Plant Protection, Yunnan Agricultural University, it was found that Jingdan 15 is susceptible/moderately resistant to northern leaf blight, moderately resistant/resistant to gray leaf spot, moderately resistant/resistant to stem rot, susceptible/moderately to ear rot, susceptible/moderately resistant to southern leaf blight, moderately resistant to sheath blight, and moderately resistant to southern corn rust.

5 Key points of cultivation and seed production

5.1 Key points of cultivation technique

The soil should be prepared finely, and sufficient base fertilizer should be applied. When the rainy season comes, all the seedlings were planted in one time, at a density of 7.2×10-7.5×10plants/ha. Single-row single-plant or double-row double-plant was adopted. Seedling thinning is carried out in time and fertilization is conducted early. At the 3-4-leaf stage, seedling thinning is carried out to prevent crowding. At the 5-6-leaf stage, the seedlings are fixed, and diseased, miscellaneous and weak seedlings are removed. At the same time of seedling fixation, 150-225 kg/ha of urea is applied as seedling fertilizer, in combination with tillage and soil loosening. Emphasis is placed on ear fertilizer. At the 10-11-leaf stage, 375-450 kg/ha of urea is applied, followed by tillage and soil loosening. If larvae of

Spodoptera

frugiperda

are found in the field, emamectin benzoate should be sprayed after sunset in a timely manner, and attention should be paid to spraying heart leaves. Harvest and drying should be conducted in time.

5.2 Key points of seed production

The seed production fields should be concentrated and contiguous, and have sufficient light and convenient irrigation and drainage. Spring sow is usually adopted for seed production. No other maize cultivar is planted 500 m upwind and 300 m downwind the seed production area. The male parent is sown by stages, 50% for the first stage at the same time as the female parent, and 50% for the second stage 5 d after the sowing of the female parent, in order to ensure flowering synchronization. Weeds in fields are removed in a timely manner. The female parent is castrated in time. Harvest and drying should be conducted in time.