Xinwei SONG,Jianrong LIN,Mingguo WU，Guanhai RUAN

1.China National Rice Research Institute,Hangzhou 310006,China;

2.Zhejiang Academy of Agricultural Sciences,Hangzhou 310021,China

The Breeding of New Indica-japonica Intersubspecific Hybrid Rice Combination Chunyou 84

Xinwei SONG1*,Jianrong LIN1,Mingguo WU1，Guanhai RUAN2

1.China National Rice Research Institute,Hangzhou 310006,China;

2.Zhejiang Academy of Agricultural Sciences,Hangzhou 310021,China

Chunyou 84 is an indica-japonica hybrid rice combination developed from Chunjiang 16A,a late japonica CMS line with early anthesis time,and C84,an indica-japonica intermediate type restorer line with wide compatibility.It has the characteristics of high yield potential,high seed production,excellent agronomic characters, good resistance and wide adaptability.It was registered and released by Zhejiang Provincial Crop Variety Appraisal Committee in March,2013.The breeding procedure,characteristics,major techniques of cultivation and seed production of Chunyou 84 were introduced in this paper.

Intersubspecific hybrid rice;Chunyou 84;High yield;Breeding

I n recent years,it has already been proved by practice that an efficient path to guarantee increasingly rice yield in China is the utilization of the strong hybrid vigour of indica-japonica intersubspecific hybrid rice,however,in the present popularization and application of indica-japonica intersubspecific hybrid rice,there have been many problems,such as low seed production,poor grain plumpness in the later stage,etc[1-5].Therefore,actively demonstrating and popularizing indica-japonica intersubspecific hybrid rice combination with high seed production,strong hybrid vigour and good colouring in the later grain filling stage meets the current market requirement of rice production,which has important significance for further promoting rice production and guaranteeing food security in China.Chunyou 84,an indica-japonica hybrid rice combination with super high yield bred by China National Rice Research Institute and Zhejiang Nongke Seed Industry Co.,Ltd.,developed from Chunjiang 16A which is a late japonica CMS line with early anthesis time and C84 which is an indica-japonica intermediate type restorer line with wide compatibility.It has the characteristics of high yield and high yield-increasing potential,high seed production,excellent agronomic characters,good resistance and wide adaptability.It was registered and released by Zhejiang Provincial Crop Variety Appraisal Committee in March,2013.It is a promising new indica-japonica intermediate combination.

Breeding Process

Chunjiang 16A,developed by crossing cytoplasmic sterile line Ning 67A which is a Dian-type japonica rice CMS line with male parent Chunjiang 16 which is a dwarf early-ripening ma-

Main Characteristics

Yield performance

Chunyou 84 was one of the regional trial varieties of Zhejiang single late japonica rice in 2010,its average yield was 10.05 t/hm2,which increased by 19.8%compared with Jiayou No.2, thus reaching extremely significant level,and ranking the first,the yieldincreasing point rate was 100%;in 2011,it was also one of the regional trial varieties of Zhejiang single late japonica rice,its average yield was 10.53 t/hm2,which increased by 26.1% compared with Jiayou No.2(CK),also reaching extremely significant level, and ranking the second,the yield-increasing point rate was 100%.In 2012,Chunyou 84 was one of the production testing varieties of Zhejiang single late japonica rice,its average yield was 9.87 t/hm2,which increased by 13.0%compared with CK.In the trial planting,Chunyou 84 showed the characteristics of high yield,fertilizer tolerance and lodging resistance and great yield-increasing potential,generally the yield of single cropping late rice was 9.75-10.50 t/hm2,and parcels of high rice field can reach above 11.25 t/hm2.

Main agronomic traits

Chunyou 84 has strong photonasty,it was cultivated as single cropping late rice in Zhejiang Province, its growth period was 156.7 d.Chunyou 84 has the characteristics of short and strong plants at the seedling stage,better seedling flexibility,being not easy to be bad after transplanting, turning green quickly,medium tillering ability,vigorous vegetative growth, luxuriant growth,thick and strong stalk,moderate height,compact plant type,strong lodging-resistance capability,concentrated heading,dark green leaf,tall and straight stem leaf, good form for light interception,strong cold endurance at the later period and good colouring.From the regional trial data of Zhejiang single late japonica rice during 2010-2011(Table 1),it was shown that the plant height of Chunyou 84 was 120.0 cm,the panicle length was 18.7 cm,the number of effective panicles was 210.0×104/hm2, total grains of each panicle were 244.9,theseed setting percentage was 83.6%and 1 000-seed weight was 25.2 g.

Indica-japonica characteristics

The female parent and male par-ent of Chunyou 84 were Chunjiang 16A and C84,respectively;based on the determination using Chen’s index, it showed that the Chen’s index of Chunjiang 16A was 19,belonged to japonica type,and that of C84 was 15, and it was japonica-cline type,indicating that C84 was not typical japonica restorer line,but indica-japonica intermediate type restorer line[7],therefore, Chunyou 84 was an indica-japonica (japonica-cline type)hybrid rice combination.

Table 1The main agronomic traits of Chunyou 84

Quality characters

According to the detection results of Rice and Its Products Quality Supervision and Inspection Center,Ministry of Agriculture of the People’s Republic of China during 2010-2011, Chunyou 84 had 82.2%brown rice rate,73.0%milled rice rate,65.9% head rice rate,5.6 mm grain length, 2.0 length-width ratio,71%chalkiness grain rate,11.3%chalkiness ratio,3-grade transparency,5.7-grade alkali spreading value,80 mm gel consistency,16.8%amylose content and 10.0%protein content.

Resistance

Based on the resistance identification results of Institute of Plant Protection and Microbiology,Zhejiang A-cademy of Agricultural Sciences during 2010-2011,Chunyou 84 had 0.3-grade leaf blast,1.0%spike blast loss ratio,1.7 comprehensive index of rice blast,6.0-grade bacterial blight,9-grade brown rice planthopper and 1.0-grade rice stipe virus.By comprehensive assessment,Chunyou 84 had moderate resistance in rice blast,and good resistance in bacterial blight, brown rice planthopper and rice stipe virus.

Suitable planting areas

After many years of planting experimentally,it preliminarily showed that Chunyou 84 had wide application range,it was mainly suitable to plant as single cropping rice or continuous cropping late rice in the middle and lower reaches of Changjiang River, such as Zhejiang,Anhui,Hubei,etc., and as single-season rice or continuous cropping late rice in Jiangxi,Hu’nan,Fujian,etc.

Yield of hybrid seed production

As the female parent of Chunyou 84,Chunjiang 16A is a late japonica CMS line with early anthesis time,and as the male parent of Chunyou 84, C84 is an indica-japonica intermediate type restorer line with wide compatibility,and its flowering time is obviously later than common indica type rice restorer line,the flowering time difference is obviously shorter than common inter-subspecific hybrid rice, moreover,C84 has large spike shape, adequate pollen quantity and good pollen quality,so the yield of seed production of Chunyou 84 is high.In 2012,Zhejiang Nongke Seed Industry Co.,Ltd.produced 33.3 hm2hybrid seeds in Nanxun District of Huzhou City in Zhejiang Province and Fengxian District of Shanghai,its average yield reached 2.25 t/hm2.

Main Points of Cultivation Techniques

Sowing timely

Chunyou 84 can be sowed as single cropping late rice in Zhejiang Province from middle and late May to early June.The seeding quantity for raising rice seedlings can be among 90.0-120.0 kg/hm2,and the sowing quantity for field planting can be among 9.0-12.0 kg/hm2,dry land and wet land for seedlings are both suitable,adequate fertilizer and sparse seeding are required for strong seedlings with tillers,the seedling age must be about 25 d;for mechanical transplanting rice, the sowing quantity can be 18.0 kg/ hm2,the seedling age can be among 18-20 d;for direct-seeding cultivation, the sowing quantity should be among 18.8-22.5 kg/hm2.

Rational close planting

Chunyou 84 has moderate tillering ability,many kernels per spike and high setting percentage,the number of effective spikes is a key factor for high yield of Chunyou 84.To increase the number of effective spikes,manual transplanting should be carried out for single cropping late rice,the planting distance of field planting can be 20.0 cm×26.7 cm,1-2 plants for each cluster;the planting distance of machine transplanting of rice can be 30.0 cm× 21.0 cm,1-2 plants for each cluster.

Nutrient and water management

Chunyou 84 needs more fertilizer and has high fertilizer tolerance and lodging resistance,generally,the land with middle fertility needs about 210 kg/hm2pure nitrogen.The fertilizing methods are:base fertilizer should be applied heavily,organic fertilizer accounts for the largest,appropriate phosphorus-potassium fertilizer is also required,tillering fertilizer should be applied early,fertilization for head sprouting should be applied in the later period,N:P:K must be 1:0.5:1.The irrigation should follow shallow water,in the later stage,moistening irrigation is dominant and it is also mixed with the alternation of wetting and drying,water cut-off can not be too early.

Pest control

Before sowing,the seed should be treated with medicament to prevent bakanae disease;during rice seedling stage,rice thrips should be paid attention to preventing;during prime field period,some plant diseases and insect pests like snout moth’s larva, aphid,brown rice planthopper,false smut and banded sclerotial blight should be paid attention to preventing.

Main Points of Seed Production Techniques

Choosing seed production field

The spatial isolation of the field for seed production must be more than 100 m,and the time isolation must be more than 20 d.

Timely and sparsely sowing for cultivating strong seedlings with tillers

According to the characteristics and features of the parents and the climatic features of Zhejiang,the male parent of the second stage should be made for hybrid seed production,the male parent C84 of the first stage should be sowed on May 30 and that of the second stage should be sowed on June 7;the female parent Chunjiang 16A should be sowed on June 1; all these are to ensure the flower synchronization of the parents.The sowing quantity of female parent for field planting should be among 22.5-30.0 kg/hm2,and that of male parent should be among 4.5-6.0 kg/hm2;nutrient and water management during the seedling stage must be strengthened, and rice seedlings for transplanting must be 1-2 tillers.

Transplanting in the suitable period and rationally arranging row ratio

The seedling age should be about 25 d when transplanting,multiple plants of male parent should be planted in double rows,and female parent should also be planted with multiple plants,the row ratio of male parent to female parent should be 2∶10 and the planting space should be 16.7 cm× 18.3 cm.

Rationally applying fertilizer,scientifically managing water,and doing well in disease and insect control

To ensure the vigorous growth of female parent,base fertilizer shoudl be applied adequately;to prompt male parent become large panicle,topdressing should be applied early and appropriate phosphorus and potassium fertilizer must also be used together;for water management,there should be deepwater in the period of seedling establishment and shallow water in the tillering stage,and the rules of the alternation of wetting and drying,watering for booting,pellicular water for flowering and flowing water for raising rice should be followed; meanwhile,the pest control should be paid attention to,such as snout moth's larva,banded sclerotial blight,brown rice planthopper,etc.

Artificial supplementary pollination, and applying GA3 timely and appropriately

Generally,the dosage of GA3 is 90-120 g/hm2,and it should be applied twice,the first time is at the 10% heading stage of the parents and the dosage is 45-75 g/hm2,1-2 days after that,the second dosage should be 45 g/hm2.At the same time,at the rupturing stage of female parent,50%flag leaves should be cut out;at the peak flowering stage,artificial supplementary pollination should be done well.

Roguing strictly and harvesting timely

To prevent out-crossing,the isolation work must be done strictly;at the seedling stage and field stage,detaselling work must also be done strictly;before initial heading stage, unusual plants should be removed completely;after artificial?pollination, the male parent must be cut out timely, and the plants should be harvested at the right time to prevent mechanical mixing,thereby ensuring the purity and quality of seeds.

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[2]QIAN XM(钱兴苗),MA YC(马寅超),MA RR(马荣荣),et al.Performance of indica-japonica hybrid late rice combination Yongyou 9 and key points of its cultivation(籼粳杂交晚稻甬优9号的试种表现及栽培要点)[J].Journal of Zhejiang A-gricultural Sciences(浙江农业科学), 2008(2):198.

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[4]WU MG(吴明国),LIN JR(林建荣), SONG XW(宋昕蔚),et al.Breeding of new japonica-indica hybrid rice combination Chunyou 59(粳不籼恢亚种间杂交水稻新组合春优59的选育)[J].Hybrid Rice(杂交水稻),2010,25(1):16-17.

[5]YANG WG(杨伟国),WANG C(王超), JIN ZJ(金仲锦),et al.Characteristics and high-yielding cultivation techniques of Yongyou 12(甬优12特征特性与高产栽培技术)[J].China Rice(中国稻米), 2011,17(3):62,64.

[6]LIN JR(林建荣),WU MG(吴明国),RUAN GH(阮关海),et al.Breeding and utilization of late japonica CMS line Chunjiang 16A with early flowering,dwarf and early maturity(早花时矮秆早熟粳稻不育系春江16A的选育与利用)[J]. China Rice(中国稻米),2006(6):17-18. [7]LIN JR(林建荣),SOPNG WX(宋昕蔚), WU MG(吴明国).Biological characteristics and heterosis utilization of four indica-japonica intermediate type restorer lines with wide compatibility(4份籼粳中间型广亲和恢复系的生物学特性及其杂种优势利用)[J].Chinese Journal of Rice Science(中国水稻科学),2012,26 (6):652-662.

Responsible editor:Nanling WANG

Responsible proofreader:Xiaoyan WU

籼粳亚种间杂交稻春优84的选育

宋昕蔚1*，林建荣1，吴明国1，阮关海2
（1．中国水稻研究所，浙江杭州310006；2．浙江省农业科学院，浙江杭州310021）

春优84是利用早花时晚粳不育系春江16A与籼粳中间型广亲和恢复系C84配组育成的粳不籼恢亚种间杂交稻新组合。该组合具有产量潜力大、制种产量高、综合农艺性状优良、抗瘟性较好、适应性广等优点，2013年3月通过浙江省农作物品种审定委员会审定。介绍了该组合的选育过程、主要特征特性、栽培技术及制种技术要点。

亚种间杂交稻；春优84；高产；选育terial,and followed by successive fertility identification for many generations and backcrossing,these were carried out by China National Rice Research Institute and Zhejiang Nongke Seed Industry Co.,Ltd.It passed the sterile line identification of Science Technology Department of Zhejiang Province in September,2005[6].Restorer line C84,an indica-japonica intermediate type restorer line with wide compatibility[7],bred by China National Rice Research Institute and Zhejiang Nongke Seed Industry Co.,Ltd.from the hybridization between japonica restorer with wide compatibility(G070×Chunhui 58)and indica restorer CH172 with wide compatibility.In autumn of 2005, the cross combination(G070×Chunhui 58)×CH172 was prepared;in spring of 2006,generation-adding propagation was carried out in Hainan; in autumn of 2006,850 strains of F2generation were planted in Hangzhou, and 35 plants with thick and strong stalk and larger spikes were chosen;in spring of 2007,35 strains of F3generation were planted in Hainan,and 49 plants with thick and strong stalk and larger spikes were chosen;in autumn of 2007,49 strains of F4generation were planted in Hangzhou,and the screening of agronomic trait and the identification of resistance and rice quality were done,finally 18 plants with thick and strong stalk,good disease-resistance,large spikes and high yield were chosen;in spring of 2008, 18 strains of F5generation were planted in Hainan,3 strains with thick and strong stalk,good disease-resistance, large spikes,high and uniformly stable yield were chosen to carry out the determination of fertility recovery capability using japonica rice sterile line Chunjiang 12A and indica rice sterile line II-32A;in autumn of 2008,test cross F1 and tester parent were planted in Hangzhou,based on the fertility and seed setting rate of test cross F1, restorer line C84 with good agronomic trait,strong lodging resistance and large spikes and wide compatibility was bred,and man-made seed production of Chunjiang 16A×C84 was carried out.In spring of 2009,the identification on agronomic trait and yield of Chunjiang 16A×C84 was carried out in Hainan,and the performance was good,therefore,the production of hybrid seeds was carried out using Chunjiang 16A and C84;in autumn of 2009,Chunjiang 16A×C84 was taken to take part in regional trial of Hangzhou single late japonica rice in Zhejiang Province,its performance was outstanding,finally it was named as Chunyou 84;in 2010,Chunyou 84 was one of the regional trial varieties of Zhejiang single late japonica rice;in 2011,it was also one of the regional trial varieties of Zhejiang single late japonica rice;in 2012,it was taken to take part in production test of Zhejiang single late japonica rice;in 2013,it was registered and released by Zhejiang Provincial Crop Variety Appraisal Committee(Zheshendao 2013020); during 2012-2013,it was taken to take part in South China rice regional trial of single late japonica rice.

浙江省0406项目；农业部“中国超级稻选育与试验示范”项目；中国水稻研究所基本科研业务费项目（2012R G001-2）；国家农业科技转化资金项目（2013GB23260592）；浙江省“三农六方”农业科技协作计划项目；浙江省公益技术研究农业项目(2012C22023)。

宋昕蔚（1979-），女，浙江杭州人，助理研究员，硕士，从事水稻育种方面的研究工作，E-mail：songxw129@hotmail.com。*通讯作者。

2015-03-26

修回日期 2015-06-12

Supported by Zhejiang 0406 Project;the Project of"The Breeding and Experimental Demonstration of Chinese Super Rice"by Ministry of Agriculture;the Project of Fundamental Research Funds of China National Rice Research Institute(2012R G001-2);National Agricultural Science and Technology Transformation Fund Project (2013GB23260592);Zhejiang Agricultural Science and Technology Cooperation Projects of"Three Agricultural Issues and Six Parties";Zhejiang Agricultural Project of Public Welfare Technology Research(2012C22023).

*Corresponding author.E-mail:songxw129@hotmail.com

Received:March 26,2015 Accepted:June 12,2015