Breeding of Yujingyou 50, a New Late

Fei ZHU Yiqin YU Yuping HU Yun’an DU Fengqin YU Xiaolin CHENG Xinjian ZOU Jinhe HU

Hybrid Rice Combination with Good Quality

Abstract Yujingyou 50 is a new high-quality late indica hybrid rice combination selected by Institute of Grain and Oil Crops， Nanchang Academy of Agricultural Sciences and Hunan Zhonglang seed Industry Co.， Ltd. The combination matured 3 d earlier than Tianyouzhan. It has the characteristics of moderate plant type， broad and long flag leaves， general tillering ability， colorless palea tips， large panicles with many grains， high seed setting rate， average 1 000-grain weight， good color change at maturity， and rice quality reaching grade 2 of ministry standard. It was approved by the Jiangxi Provincial Crop Variety Approval Committee on March 18， 2021. This paper introduced the breeding process， characteristics， cultivation techniques and key points of seed production of this variety.

Key words High quality; Hybrid rice; Yujingyou 50; Breeding

Received： November 3， 2021  Accepted： January 5， 2022

Supported by Jiangxi Provincial R&D Program （20181BBF60007）.

Fei ZHU （1984-）， male， P. R. China， research assistant， devoted to research about breeding and promotion of new rice varieties.

*Corresponding author. E-mail： yangzi810603@163.com.

The breeding of high-quality hybrid rice focuses on greatly improving the quality of rice without affecting the yield， while the quality of hybrid rice depends on the quality of the parents[1].  The chalkiness of hybrid rice is mainly affected by sterile lines[2]. Therefore， breeding sterile lines with good rice quality， good combining ability and high seed production yield is the foundation， and breeding restorer lines with good rice quality， good combining ability and strong disease resistance is the key[3]. Yujingyou 50 is a new high-quality three-line mid-to-late-maturing late indica rice combination bred by Institute of Grain and Oil Crops， Nanchang Academy of Agricultural Sciences and Hunan Zhonglang Seed Co.， Ltd.， using self-bred three-line sterile line "Yujing A" with good rice quality and good combining ability and self-fertile restorer line "Langhui 50" with good rice quality， good combining ability and strong disease resistance. The combination showed high rice quality and high yield in the regional tests of late indica combinations in Jiangxi Province in 2019-2020， and approved by Jiangxi Provincial Crop Variety Approval Committee on March 18， 2021.

Source of Parents and Selection Process

Breeding of Yujing A

Yujing A is a new three-line sterile line， which was bred through crossing of Jin 23A as the female parent and T98B//2402-3B/03-75B as the male parent， followed by multiple generations of backcrossing， and multiple years and multiple generations of generation-adding directional selection in Hainan and Hunan， and finally obtained in 2013. The sterile line has stout stems， scattered plant type， good rice quality， strong tillering ability， and large panicles with many grains. Its leaf sheaths， palea tips and stigmas are green. Its stigmas have high exposure rate， good outcrossing property and stable sterility. In May 2017， it passed the appraisal of Hunan Provincial Crop Variety Approval Committee （Table 1）.

Breeding of Langhui 50

Langhui 50 is a late-maturing restorer line bred by crossing R08-45 and R09-17 and obtained in the F9 generation. In 2009， the self-fertile intermediate material R08-45 with resistance to rice blast was used as the male parent and crossed with R09-17 used as the female parent. The F1 generation was planted in 2010. In 2010， the F2 generation was planted in the rice blast disease area of Hunan， and single plants resistant to rice blast were selected. From 2011 to 2013， the F3 and higher generation lines were systematically selected and selected under high-pressure stress of rice blast in Hainan Province and Xiangxi disease areas of Hunan Province. In 2012， excellent individual plants of the F5 generation were selected for test cross with Zhongyujing A. In 2013， the line numbered 013-50 was selected in the test cross nursery， and its test cross progeny showed obvious heterosis， high seed setting rate and good maturity. The corresponding male parent 013-50 has excellent comprehensive agronomic traits， strong resistance to rice blast， and stable traits. It was named Langhui 50 （Table 2）.

Breeding of Yujingyou 50

In 2013， Yujing A was paired with Longhui 50. In 2014， a comparative test of late mid-maturing indica combinations was carried out in Hunan. From 2015 to 2017， a multi-site test of late mid-maturing indica combinations was carried out in Jiangxi Province. Among them， Yujing A/Langhui 50 performed outstandingly， and it was tentatively named Yujing A You 50 （Table 3）.

Characteristics

Yujingyou 50 was planted as late rice in Jiangxi， with a whole growth period of 121.4 d， 3 d earlier than Tianyouzhan （CK）. It has the characteristics of moderate plant type， broad and long flag leaves， general tillering ability， colorless palea tips， large panicles with many grains， high seed setting rate， average 1 000-grain weight， good color change at maturity， and rice quality up to grade 2. The plant height was 113 cm; it had 2 857 500 effective panicles per hectare， with a percentage of ear-bearing panicles of 62.4%; the panicle length was 24.3 cm; the total number of grains per panicle was 160.65; the number of filled grains per panicle was 130.65; the seed setting rate was 81.35%; and the 1 000-grain weight was 25.4 g[5].

Yield Performance

In the regional test in Jiangxi Province in 2019， the average yield was 9 063.15 kg/hm2， which was 2.13% lower than that of Tianyouhua （CK）， which was not significant. In the continued test in 2020， the average yield was 7 984.95 kg/hm2， which was 1.31% lower than that of Tianyouhua （CK）， which was not significant. The average yield of the two-year regional test was 8 523.75 kg/hm2， which was 1.72% lower than that of Tianyouhua （CK）. In 2020， large-scale demonstration planting was carried out in Nanchang， Yichun， Fuzhou， Shangrao， Ganzhou and other places， with a general yield of 8 250 kg/hm2[5].

Rice Quality and Resistance

Rice quality

The results of rice quality analysis in Jiangxi Province in 2019 were as follows： husked rice yield 81.1%， milled rice rate 74.1%， head rice rate 71.6%， grain length 6.8 mm， grain length-width ratio 3.4， percentage of chalky rice 10%， chalkiness degree 2.4%， amylose content 15.8%， gel consistency 65 mm， alkali spreading value 6.5， transparency grade 1， and moisture content 12.1%. The rice quality reached the ministry standard of grade 2[5] （Table 4）.

Resistance

Identification results of rice blast resistance under natural induction：

2019： It had neck blast resistance of grade 9， and was highly susceptible to rice blast; and the average neck blast loss rate was 13.9%.

2020： It had neck blast resistance of grade 9， and was highly susceptible to rice blast; and the average neck blast loss rate was 21.0%[5].

Key Points of Seed Production Technology

Seeding

Yujingyou 50 is sown in late summer in Fujian after tobacco production. The male parent is sown on June 5 for the first phase and on June 12 for the second phase， and the female parent is sown on June 23. The leaf difference of the male and female parents is 4.5 leaves， and the time difference is 18 d. The two parents originally start to head around August 25.

Transplanting

Do a good job in the management of nutrients and water in the field： Yujing A has medium tillering ability and average seed setting， and transplanting enough basic seedlings is the key. The row ratio for transplanting is 1∶8. The male parent is inserted according to the size of 8 inches × 6 inches， and the female parent is inserted according to the size of 4 inches × 5 inches. Each hole is planted with two seedlings. The base fertilizer is mainly organic fertilizer， and topdressing is performed early. Fertilization is performed once 5 d after planting the male plant to ensure the growth of the male parent and ensure sufficient pollen during pollination. Topdressing is performed early to ensure that the seedlings reach the highest quantity 15 d after the female parent is planted.

Nutrient and water management

Enough base fertilizer is applied. The tiller fertilizer is applied early. Before transplanting， the seedling lifting fertilizer and seedling lifting drugs are applied.

Spray "gibberellic acid （920）"， and do a good job of artificial pollination

The hybrid is sensitive to gibberellic acid. Gibberellic acid is sprayed at a rate of 120 g/hm2 when 15% of the plants of the female parent have headed， and at a rate of 120 g/hm2 the next day. It is necessary to do a good job of artificial pollination， and artificial pollination is performed 3-4 times a day during the peak pollen-dispersing period of the male parent to increase the rate of outcrossing.

Disease and pest control

The seeds of the parents are disinfected. Nitrogen fertilizer is applied early in the field. In the middle and late stages， the application of nitrogen fertilizer is controlled， while phosphorus and potassium fertilizers are increased. It is necessary to timely control various diseases and pests according to the information on diseases and pests.

Yield

The general yield is 2 625-3 000 kg/hm2.

Fei ZHU et al. Breeding of Yujingyou 50， a New Late Hybrid Rice Combination with Good Quality

References

[1] LIAO FM， ZHOU KL， YANG HH， et al. Study on the status quo of rice quality of indica three-line hybrid rice[J]. Hybrid Rice， 1999， 14（6）： 35-38. （in Chinese）.

[2] LIANG SH， LI CG， WU YY， et al. Effects of sterile rice lines on the quality traits of their hybrids[J]. Fujian Science and Technology of Rice and Wheat， 2000， 25（4）：1-2. （in Chinese）.

[3] LI H， JIANG JW， ZHU HW， et al. Breeding of new hybrid rice combination ‘Shengtaiyou 018’ with fine grain quality[J]. 2017， 31（6）： 648-650. （in Chinese）.

[4] LUO QC， CHEN YM， CHEN CH， et al. Breedina of new good grain quailty rice variety Guijing 1 and cultivation technique for obtaining high yield and quality [J]. Guangxi Agricultural Sciences， 2009， 40 （9）： 1142-1143. （in Chinese）.

[5] Jiangxi Provincial Seed Administration. Compilation of regional test data of new rice varieties in Jiangxi Province in 2020. （in Chinese）.

Editor： Yingzhi GUANG  Proofreader： Xinxiu ZHU