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Abstract Yuanliangyou 1000 is new combination of semilate rice bred by Yuan S and R900 by Institute of Grain and Oil Crops of Nanchang Academy of Agricultural Science， Yuanshi Seed Industry High Tech Co.， Ltd. and Jiangxi Pusheng Agricultural Development Co.， Ltd. It passed through new variety certification of Jiangxi Province in 2017， and approval number was Ganshendao 20170020， which was suitable for plantation of semilate rice in Jiangxi. In this paper， breeding process， combination characteristic， main cultivation technique and seed production technology of Yuanliangyou 1000 were introduced.
Key words Semilate rice; New combination; Yuanliangyou 1000; Breeding process
Jiangxi Province is in middle and lower reaches of the Yangtze River， and it is one of 13 main rice producing provinces， one of two provinces providing food to the state without interruption since the founding of China， as well as main production region of early and late indica rice in China. In recent years， with adjustment of agricultural supply side structure， plantation area of early and late rice decreases， while plantation area of semilate rice continuously increases. The breeding of excellent new variety （combination） of semilate rice has an important role in the development of Jiangxi rice industry and guaranteeing national food security[1-2]. Yuanliangyou 1000 is new combination of semilate rice bred by Yuan S and R900 by Institute of Grain and Oil Crops of Nanchang Academy of Agricultural Science， Yuanshi Seed Industry High Tech Co.， Ltd. and Jiangxi Pusheng Agricultural Development Co.， Ltd. The combination has large potential of yield increase， stronger resistance to rice blast， strong stem and lodging resistance， and appearance and taste quality are better. It passed through new variety certification of Jiangxi Province in 2017， and approval number was Ganshendao 20170020， which was suitable for plantation of semilate rice in Jiangxi.
Breeding process of the combination
Breeding of female parent Yuan S
Yuan S was bred by Yuanshi Seed Industry High Tech Co.， Ltd. in summer of 2006， and female parent was DGMS C81S with better agronomic characters and lower sterile starting temperature， while Q127 was male parent. C81S was from Y58S/ and 620S//F21， while Q127 was from 8WR91 which was a lodging resistant material in International Rice Institute. Via the stress selection of short days and low temperature in Hainan， long days and low temperature in summer of Changsha， short days and low temperature in autumn of Changsha， dualpurpose genic male sterile line Yuan S with excellent quality， ideal plant shape and low sterile starting temperature was bred in 2011 by 10 generations of directional breeding in 5 years. Breeding of male parent R900
Male parent was the combination of R900 and Y Liangyou 900， and was from Hunan Yuanchuang Super Rice Technology Co.， Ltd.， and authorization number of plant variety was CNA20120634.6.
Combination breeding
Self bred indica type of dual purpose genic male sterile line Yuan S was female parent， while medium indica rice restorer line R900 bred by Hunan Yuanchuang Super Rice Technology Co.， Ltd. was taken as male parent for testcross. It was bred by multipleyear identification， screening and variety comparative test， and was named as Yuanliangyou 900. During 2015-2016， it joined in regional trial of Jiangxi and performed well. It passed through new rice variety certification of Jiangxi Province in 2017， with approval number of Ganshendao 20170020， and its name was Yuanliangyou 1000.
Parents characteristics
Characteristics of female parent
Yuan S is 80 cm high， with strong stem， moderate plant shape and straight blade. There are 13-15 leaves on main stem， and leaf is light green. Coleoptile and leaf sheath are green， while auricle and leaf pillow are light green. It has stronger tillering ability and high spike forming rate. Yuan S has big spike and more grains， and spike length is 25.8 cm. Total grain number per spike is 115-185， and mean is 135， while grain density is moderate. Its cervix degree is small， and cervix grain rate is only 6.8% without spraying "920". The grain is 8.3 mm long and 2.5 mm wide， and ratio of length to width is 3.3. Lemma is yellow， while stigma is white， and thousandgrain weight is 25 g.
Yuan S has good outcrossing characteristics and larger spike shape， and slightly shows arc in heading and flowering period. Flowering period is 4-5 d， and flowering time is early， which is at 09：00-12：00. Flowering peak is obvious， and flowering before the noon is more than 75%， and encountering rate of flowering time is high. Cervix rate of spike is about 20%， and exsertion rate of stigma is high. Without spraying "920"， total exsertion rate of stigma is 81.2%， in which bilateral exposure rate is 34.1%. Stigma has stronger vitality， and setting rate of outcrossing could reach 50%， and seed production is easy to produce high yield. It is sensitive to "920"， and 225 g/hm 2 of "920" could relieve cervix phenomenon when heading reaches 15%-20%[3-5].
Yuan S is analyzed by Rice Quality Testing Center of Ministry of Agriculture. The analysis result shows that brown rice percentage， milled rice rate and head rice rate are 81.2%， 72.9 % and 60.3%. Grain length is 7.8 mm， and ratio of length to width is 3.2. Chalky rice rate is 21.0%， while chalkiness degree is 1.8%， and transparency reaches grade one. Alkali elimination value is grade 6.0， and gel consistency is 84 mm. Amylose content is 15.1%， while protein content is 9.6%. Among them， roughness rate， chalky rice rate， chalkiness degree and gel consistency all reach grade one of highquality rice， while head rice rate reaches grade three of highquality rice. Rice blast of Yuan S was identified in Dawei Mountain of Liuyang City in 2013. The result showed rice blast of seedling reached grade five， while rice blast of spike was grade seven， and comprehensive level reached grade 5.5. The resistance to bacterial blight reached grade five， and banded sclerotial blight was light.
Characteristics of male parent
Male parent R900 is restorer line of late maturing middle indica rice two lines. It is sown in early May in Chenzhou of Hunan， heading starts in middle dekad of August， and the duration from sowing to initial heading is about 100 d. Plant height is 95 cm， with strong stem and dark green leaves. Flag leaf is broad， thick and straight， which is 30-35 cm long and 3.0-3.5 cm wide. Spike is straight and large， while average spikelet number per spike is 350-450， and secondary branch is developed. Grain density is large， and setting rate reaches more than 85%， while thousandgrain weight is 24 g. Leaf sheath， leaf ear， lemma tip have no color and beard. It has restoring force on most of cms lines and worse resistance to rice blast. Resistance identification result of rice blast in disease nursery of Jinggang Mountain of Jiangxi shows that leaf rice blast， leaf blast and spike blast are grades 5， 7 and 9， with general rice quality.
Regional test results over many years
Yuanliangyou 900 joined in regional test of oneseason rice in Jiangxi Province in 2015， and average yield was 9 393.9 kg/hm 2， which increased by 4.31% than Y Liangyou 1. The yield increase was insignificant， and it was ranked fourth in the group. Average whole growth period was 132.1 d， which was 1.2 d longer than control.
Reexamination result of 2016 showed that average yield of Yuanliangyou 900 was 9 136.5 kg/hm 2， which increased by 3.40% than Y Liangyou 1. The yield increase was insignificant， and it was ranked fifth in the group. Average whole growth period was 132.4 d， which was 2.4 d longer than control.
The mean of the two years showed that average yield of Yuanliangyou 900 was 9 265.2 kg/hm 2， which increased by 3.86% than Y Liangyou 1. Whole growth period was 132.3 d， which was 1.8 d longer than control.
Production test and demonstration results of multiplepoint test in the province
Oneseason rice variety production test of Yuanliangyou 900 was respectively conducted in Yugan， Xiushui， Fengxin， Pingxiang and Yongxiu of Jiangxi Province in 2016 by Jiangxi Seed Bureau. The combination had better plant and leaf shapes， good growth and stronger lodging resistance， without obvious defect. It passed through expert field inspection of oneseason rice production test organized by Jiangxi Crop Variety Approval Committee. In 2016， Jiangxi Pusheng Agricultural Development Co.， Ltd. set oneseason rice test demonstration of Yuanliangyou 900 combination. 0.1-0.2 hm 2 of plantation demonstration was set in Mashan Base of Pingxiang， Qianshan Seed Bureau， Yongxiu Seed Station， and Y Liangyou 1 was control. According to the statistics of 3 demonstration points， average yield was 9 798.0-10 857.0 kg/hm 2， which increased by 3.48%-6.92% than control. Whole growth period was 132.6 d， which was 2.3 d longer than control. The combination had better plant and leaf shapes， good lodging resistance， large spike， more grains， and good maturity phase. Yield potential was large， and taste and appearance quality were good， and it was suitable for oneseason rice plantation in Jiangxi （Table 1）.
Main characteristics
Whole growth period
In regional test of late rice in Jiangxi Province in 2015， its growth period was 132.1 d，which was 1.2 d longer than control. In continued trial of late rice in Jiangxi Province in 2016， whole growth period was 132.4 d， which was 2.4 d longer than control. Average whole growth period of the two years was 132.3 d， which was 1.8 d longer than control.
Rice quality
Quality analysis in regional trial of Jiangxi Province was conducted by Food Quality Supervision and Testing Center （Wuhan）of Ministry of Agriculture. Rice quality of Yuanliangyou 900 did not reach grade three， but appearance and eating quality were better than control （Table 2）. The variety had good appearance quality， softer rice and good palatability， which corresponded with the demand of living standard rising day by day.
Resistance
Regional trial result of Jiangxi during 2015-2016 showed that the resistance of Yuanliangyou 900 to rice blast in main disease region of Jiangxi Province was obviously stronger than control. Diseased ear rate was about 1/2 of control， and loss rate of panicle blast was about 1/3 of control， while comprehensive index was about 1/2 of control. Identification result of rice blast in regional trial of 2015 showed that panicle blast was grade nine， and it was highly sensitive to rice blast. Diseased panicle rate was 41.0%， and loss rate of panicle blast was 14.9%. In trial group， it was in moderate disease resistance level， and its resistance was obviously better than control. In continuous test of 2016， it was identified that panicle blast was grade nine， and it was highly sensitive to rice blast. Disease panicle rate was 53.0%， while loss rate of panicle blast reached 16.4%， and comprehensive index of rice blast reached grade 4.5. In trial group， it was at moderate resistance level， and its resistance was obviously better than control （Table 3）. Agricultural Biotechnology2018
Agronomic characters
The variety has compact plant shape and dark green leaf， and flag leaf is short， broad and straight. Field growth is handsome， with strong tillering ability. There is more effective panicle， apex of lemma is purplish， with large spike and more grains. Setting rate is higher， and thousandgrain weight is lighter， and color turning during mature period is better. Regional trial result during 2015-2016 showed that average plant height of the two years was 111.7 cm， and effective panicle reached 2 730 000 ears/hm 2， with spike formation rate of 63.7%. Total grain number per spike was 194.5， and setting rate was 75.6%-85.4%， and thousandgrain weight reached 23.6 g.
Cultivation techniques
Sowing and raising seedlings
Oneseason rice cultivation was carried out in Jiangxi Province， and it was sown during May 15-20. Seed was soaked by strong chlorin or prochloraz， with less soaking and more exposition， which could promote consistent and uniform germination. Sowing rate of rice seedling bed was 225 kg/hm 2， and seed use amount of field was 15 kg/hm 2. Paclobutrazol was sprayed during oneleaf and oneheart period， and timely topdressing was conducted during twoleaf and oneheart period. The seedling with fertilizer and pesticide was transplanted.
Transplantation
The seedlings with 5-6leaves were transplanted， and the longest seedling age did not exceed 30 days. It was suggested that planting density was 20.0 cm×26.7 cm， and planting number was 180 000-195 000 clumps/hm 2. 2 seedlings were planted in each clump， and basic seedlings per hm 2 reached 750 000-900 000. Shallow insertion was advocated， which was conducive to early renascence， and made effective panicle reach 2 250 000-2 700 000 ears/hm 2.
Fertilization management
The variety had strong stem， lodging resistance and higher fertilization level. Fertilization principle of heavy in prior period， light in middle period and supplement in latter period was used， and 210 kg/hm 2 of pure nitrogen was fertilized， and N∶P2O5∶K2O was 1∶0.5∶0.9. More base fertilizer was used， and topdressing should be conducted early， and moderate panicle fertilizer was used. Base fertilizer contained 40% of nitrogen fertilizer and 50% of phosphate fertilizer. Tillering fertilizer was used within 5 days after transplantation， and it contained 20% of nitrogen fertilizer and 50% of phosphorus and potassium fertilizer. In period 4 of young ear differentiation， 45-75 kg/hm 2 of urea and 105-120 kg/hm 2 of potash fertilizer were taken as panicle fertilizer. Water management
In water management， deep water was used to turn green， while shallow water was used for tillering. When total seedling number reached 2 550 000-2 700 000 seedlings/hm 2 （equivalent to final ear number）， field could be dried， and its field drying degree was determined by seedling growth， soil texture and weather situation. Wetness was dominant in early booting stage， and it maintained water layer on field surface in middle and latter periods， and shallow water was maintained in heading period. Humid irrigation was conducted in grouting period， dry and wet， and water was stopped in 7 d before harvest.
Prevention and control of diseases， pests and weeds
Pesticide was used to soak seed to prevent disease. According to disease and insect forecast in field period， it could timely use pesticide to prevent and control banded sclerotial blight， rice blast， snout moths larva and rice planthopper. With 7 days after transplantation， herbicide was used to remove weeds in the field by combining the first topdressing.
Seed production techniques
Correctly arranging sowing and transplanting periods， to ensure florescence encountering
Yuan S was sown in Changsha on May 25， and transplanted on June 12. Initial heading started from August 19， and the duration from sowing to initial heading was 85 d. The duration from sowing of male parent R900 to initial heading was 100 d. Sowing and transplanting periods of summer seed production of Yuanliangyou 900 in Chenzhou of Hunan were as below： time difference was about 15 d， and leaf difference was 6.0 leaves. Male parent was sown on May 1， while sowing period of female parent was on May 16， and heading and flowering stage was during August 10-30.
Rational close planting
Seed use amount of female parent in seed production field was 30 kg/hm 2， and seedling age was 20-23 d. Seed use amount of male parent was 7.5 kg/hm 2， and seedling age was 30 d. Parent line ratio was 2∶（13-14）， and rowing space of female parent used 13.3 cm×16.7 cm. Two grains of rice seedlings were planted， and 345 000-375 000 clumps/hm 2 of basic seedlings were planted. Male parent used large double lines， and rowing space used 16.7 cm×20.0 cm.
Fertilization management
Basic fertilizer of field was dominant by organic fertilizer， and it should use more base fertilizer and early topdressing. Total fertilization amount was converted to 165 kg/hm 2 of pure nitrogen， and the ratio of nitrogen， phosphorus and potash fertilizer was 1∶0.6∶0.8. In 5 days after male parent was cultivated， 151515 of threeelement compound fertilizer （75 kg/hm 2） was used once， to promote tillering. The fertilization method of sufficient base fertilizer and early topdressing was used. 25% of compound fertilizer for rice （600 kg/hm 2） was fertilized when raking field， and 150 kg/hm 2 of urea and potash fertilizer were fertilized in 3 days after planted female parent. In period 5 of young spike differentiation， 45% of compound fertilizer （75 kg/hm 2） and potassium chloride （150 kg/hm 2） were used as panicle fertilizer to improve setting rate. Water management
Shallow water irrigation was dominant. Root lived in inch water， and tillering was conducted by thin water， while field was basked in seedling period. Rehydration was conducted after middle stage of booting period， and 10 cm of water layer was maintained during flowering stage， to decline the influence of high temperature on setting rate. The alternation of dryness and wetness was dominant from latter period of grouting to maturity period， and water was stopped in one week before harvest.
Spraying appropriate amount of "920" in appropriate time
"920" was sprayed twice. "920" was sprayed firstly when 15%-20% of female parent broke， and the usage was 105-120 g/hm 2. When heading reached 40%， the second spraying of "920" was conducted， and the usage was 120-180 g/hm 2. Its cumulative usage was 225-300 g/hm 2.
Strictly removing miscellaneous plant， timely harvesting and ensuring quality
Miscellaneous plants should be strictly removed in whole process of seed production， especially before and after initial heading. It should timely harvest， and prevent mechanical mixing.
Pest control
It should prevent and control grey planthopper in seedling stage， to prevent dwarf. In the field， prevention and control of banded sclerotial blight， smut， rice blast， rice planthopper and rice leaf roller should be conducted. The population of seed production field was large， and the temperature was higher， and seedling was vivid green. Banded sclerotial blight and rice blast should be mainly prevented and controlled. Seedling was sprayed 1-2 times before heading by "Aimiao"， and the usage was 300 ml/hm 2[6].
References
[1] PAN RS， MAO DM， CHEN ZW， et al. Jinshan you 70， a new hybrid rice combination with weak photosensitivity[J]. Hybrid Rice， 2013， 28（1） ： 82-83. （in Chinese）.
[2]YOU Z， LIAO CM. Guangliangyou 2010， a new highyielding twoline hybrid rice combination[J]. Hybrid Rice， 2013， 28（1） ： 83-84 . （in Chinese）.
[3] ZHOU YC， PAN RS， CHEN ZW， et al. Breeding and utilization of a new rice CMS line Jinshan1A with nonchalk， aroma and good quality[J]. Fujian Science and Technology of Rice and Wheat， 2003， 21（1） ： 4-5. （in Chinese）.
[4] ZHANG JX， LIN MJ， WANG XM， et al. Breeding and application of excellentquality and highresistance restorer line Minghui 70[J]. Sanming Agricultural Science and Technology， 2002（1）： 21-25. （in Chinese）.
[5] LV DA， WANG SC， WANG J， et al. Breeding of excellentquality， highyield and midseason hybrid rice Guangliangyou 558[J]. China Seed Industry， 2011（18）：28-29. （in Chinese）.
[6] ZHOU Q， MEI KH， TU JM， et al. Breeding twoline medium hybrid rice variety Guangliangyou 16 with high yield and good quality[J]. Hubei Agricultural Sciences， 2014（14）：3239-3240. （in Chinese）.
Key words Semilate rice; New combination; Yuanliangyou 1000; Breeding process
Jiangxi Province is in middle and lower reaches of the Yangtze River， and it is one of 13 main rice producing provinces， one of two provinces providing food to the state without interruption since the founding of China， as well as main production region of early and late indica rice in China. In recent years， with adjustment of agricultural supply side structure， plantation area of early and late rice decreases， while plantation area of semilate rice continuously increases. The breeding of excellent new variety （combination） of semilate rice has an important role in the development of Jiangxi rice industry and guaranteeing national food security[1-2]. Yuanliangyou 1000 is new combination of semilate rice bred by Yuan S and R900 by Institute of Grain and Oil Crops of Nanchang Academy of Agricultural Science， Yuanshi Seed Industry High Tech Co.， Ltd. and Jiangxi Pusheng Agricultural Development Co.， Ltd. The combination has large potential of yield increase， stronger resistance to rice blast， strong stem and lodging resistance， and appearance and taste quality are better. It passed through new variety certification of Jiangxi Province in 2017， and approval number was Ganshendao 20170020， which was suitable for plantation of semilate rice in Jiangxi.
Breeding process of the combination
Breeding of female parent Yuan S
Yuan S was bred by Yuanshi Seed Industry High Tech Co.， Ltd. in summer of 2006， and female parent was DGMS C81S with better agronomic characters and lower sterile starting temperature， while Q127 was male parent. C81S was from Y58S/ and 620S//F21， while Q127 was from 8WR91 which was a lodging resistant material in International Rice Institute. Via the stress selection of short days and low temperature in Hainan， long days and low temperature in summer of Changsha， short days and low temperature in autumn of Changsha， dualpurpose genic male sterile line Yuan S with excellent quality， ideal plant shape and low sterile starting temperature was bred in 2011 by 10 generations of directional breeding in 5 years. Breeding of male parent R900
Male parent was the combination of R900 and Y Liangyou 900， and was from Hunan Yuanchuang Super Rice Technology Co.， Ltd.， and authorization number of plant variety was CNA20120634.6.
Combination breeding
Self bred indica type of dual purpose genic male sterile line Yuan S was female parent， while medium indica rice restorer line R900 bred by Hunan Yuanchuang Super Rice Technology Co.， Ltd. was taken as male parent for testcross. It was bred by multipleyear identification， screening and variety comparative test， and was named as Yuanliangyou 900. During 2015-2016， it joined in regional trial of Jiangxi and performed well. It passed through new rice variety certification of Jiangxi Province in 2017， with approval number of Ganshendao 20170020， and its name was Yuanliangyou 1000.
Parents characteristics
Characteristics of female parent
Yuan S is 80 cm high， with strong stem， moderate plant shape and straight blade. There are 13-15 leaves on main stem， and leaf is light green. Coleoptile and leaf sheath are green， while auricle and leaf pillow are light green. It has stronger tillering ability and high spike forming rate. Yuan S has big spike and more grains， and spike length is 25.8 cm. Total grain number per spike is 115-185， and mean is 135， while grain density is moderate. Its cervix degree is small， and cervix grain rate is only 6.8% without spraying "920". The grain is 8.3 mm long and 2.5 mm wide， and ratio of length to width is 3.3. Lemma is yellow， while stigma is white， and thousandgrain weight is 25 g.
Yuan S has good outcrossing characteristics and larger spike shape， and slightly shows arc in heading and flowering period. Flowering period is 4-5 d， and flowering time is early， which is at 09：00-12：00. Flowering peak is obvious， and flowering before the noon is more than 75%， and encountering rate of flowering time is high. Cervix rate of spike is about 20%， and exsertion rate of stigma is high. Without spraying "920"， total exsertion rate of stigma is 81.2%， in which bilateral exposure rate is 34.1%. Stigma has stronger vitality， and setting rate of outcrossing could reach 50%， and seed production is easy to produce high yield. It is sensitive to "920"， and 225 g/hm 2 of "920" could relieve cervix phenomenon when heading reaches 15%-20%[3-5].
Yuan S is analyzed by Rice Quality Testing Center of Ministry of Agriculture. The analysis result shows that brown rice percentage， milled rice rate and head rice rate are 81.2%， 72.9 % and 60.3%. Grain length is 7.8 mm， and ratio of length to width is 3.2. Chalky rice rate is 21.0%， while chalkiness degree is 1.8%， and transparency reaches grade one. Alkali elimination value is grade 6.0， and gel consistency is 84 mm. Amylose content is 15.1%， while protein content is 9.6%. Among them， roughness rate， chalky rice rate， chalkiness degree and gel consistency all reach grade one of highquality rice， while head rice rate reaches grade three of highquality rice. Rice blast of Yuan S was identified in Dawei Mountain of Liuyang City in 2013. The result showed rice blast of seedling reached grade five， while rice blast of spike was grade seven， and comprehensive level reached grade 5.5. The resistance to bacterial blight reached grade five， and banded sclerotial blight was light.
Characteristics of male parent
Male parent R900 is restorer line of late maturing middle indica rice two lines. It is sown in early May in Chenzhou of Hunan， heading starts in middle dekad of August， and the duration from sowing to initial heading is about 100 d. Plant height is 95 cm， with strong stem and dark green leaves. Flag leaf is broad， thick and straight， which is 30-35 cm long and 3.0-3.5 cm wide. Spike is straight and large， while average spikelet number per spike is 350-450， and secondary branch is developed. Grain density is large， and setting rate reaches more than 85%， while thousandgrain weight is 24 g. Leaf sheath， leaf ear， lemma tip have no color and beard. It has restoring force on most of cms lines and worse resistance to rice blast. Resistance identification result of rice blast in disease nursery of Jinggang Mountain of Jiangxi shows that leaf rice blast， leaf blast and spike blast are grades 5， 7 and 9， with general rice quality.
Regional test results over many years
Yuanliangyou 900 joined in regional test of oneseason rice in Jiangxi Province in 2015， and average yield was 9 393.9 kg/hm 2， which increased by 4.31% than Y Liangyou 1. The yield increase was insignificant， and it was ranked fourth in the group. Average whole growth period was 132.1 d， which was 1.2 d longer than control.
Reexamination result of 2016 showed that average yield of Yuanliangyou 900 was 9 136.5 kg/hm 2， which increased by 3.40% than Y Liangyou 1. The yield increase was insignificant， and it was ranked fifth in the group. Average whole growth period was 132.4 d， which was 2.4 d longer than control.
The mean of the two years showed that average yield of Yuanliangyou 900 was 9 265.2 kg/hm 2， which increased by 3.86% than Y Liangyou 1. Whole growth period was 132.3 d， which was 1.8 d longer than control.
Production test and demonstration results of multiplepoint test in the province
Oneseason rice variety production test of Yuanliangyou 900 was respectively conducted in Yugan， Xiushui， Fengxin， Pingxiang and Yongxiu of Jiangxi Province in 2016 by Jiangxi Seed Bureau. The combination had better plant and leaf shapes， good growth and stronger lodging resistance， without obvious defect. It passed through expert field inspection of oneseason rice production test organized by Jiangxi Crop Variety Approval Committee. In 2016， Jiangxi Pusheng Agricultural Development Co.， Ltd. set oneseason rice test demonstration of Yuanliangyou 900 combination. 0.1-0.2 hm 2 of plantation demonstration was set in Mashan Base of Pingxiang， Qianshan Seed Bureau， Yongxiu Seed Station， and Y Liangyou 1 was control. According to the statistics of 3 demonstration points， average yield was 9 798.0-10 857.0 kg/hm 2， which increased by 3.48%-6.92% than control. Whole growth period was 132.6 d， which was 2.3 d longer than control. The combination had better plant and leaf shapes， good lodging resistance， large spike， more grains， and good maturity phase. Yield potential was large， and taste and appearance quality were good， and it was suitable for oneseason rice plantation in Jiangxi （Table 1）.
Main characteristics
Whole growth period
In regional test of late rice in Jiangxi Province in 2015， its growth period was 132.1 d，which was 1.2 d longer than control. In continued trial of late rice in Jiangxi Province in 2016， whole growth period was 132.4 d， which was 2.4 d longer than control. Average whole growth period of the two years was 132.3 d， which was 1.8 d longer than control.
Rice quality
Quality analysis in regional trial of Jiangxi Province was conducted by Food Quality Supervision and Testing Center （Wuhan）of Ministry of Agriculture. Rice quality of Yuanliangyou 900 did not reach grade three， but appearance and eating quality were better than control （Table 2）. The variety had good appearance quality， softer rice and good palatability， which corresponded with the demand of living standard rising day by day.
Resistance
Regional trial result of Jiangxi during 2015-2016 showed that the resistance of Yuanliangyou 900 to rice blast in main disease region of Jiangxi Province was obviously stronger than control. Diseased ear rate was about 1/2 of control， and loss rate of panicle blast was about 1/3 of control， while comprehensive index was about 1/2 of control. Identification result of rice blast in regional trial of 2015 showed that panicle blast was grade nine， and it was highly sensitive to rice blast. Diseased panicle rate was 41.0%， and loss rate of panicle blast was 14.9%. In trial group， it was in moderate disease resistance level， and its resistance was obviously better than control. In continuous test of 2016， it was identified that panicle blast was grade nine， and it was highly sensitive to rice blast. Disease panicle rate was 53.0%， while loss rate of panicle blast reached 16.4%， and comprehensive index of rice blast reached grade 4.5. In trial group， it was at moderate resistance level， and its resistance was obviously better than control （Table 3）. Agricultural Biotechnology2018
Agronomic characters
The variety has compact plant shape and dark green leaf， and flag leaf is short， broad and straight. Field growth is handsome， with strong tillering ability. There is more effective panicle， apex of lemma is purplish， with large spike and more grains. Setting rate is higher， and thousandgrain weight is lighter， and color turning during mature period is better. Regional trial result during 2015-2016 showed that average plant height of the two years was 111.7 cm， and effective panicle reached 2 730 000 ears/hm 2， with spike formation rate of 63.7%. Total grain number per spike was 194.5， and setting rate was 75.6%-85.4%， and thousandgrain weight reached 23.6 g.
Cultivation techniques
Sowing and raising seedlings
Oneseason rice cultivation was carried out in Jiangxi Province， and it was sown during May 15-20. Seed was soaked by strong chlorin or prochloraz， with less soaking and more exposition， which could promote consistent and uniform germination. Sowing rate of rice seedling bed was 225 kg/hm 2， and seed use amount of field was 15 kg/hm 2. Paclobutrazol was sprayed during oneleaf and oneheart period， and timely topdressing was conducted during twoleaf and oneheart period. The seedling with fertilizer and pesticide was transplanted.
Transplantation
The seedlings with 5-6leaves were transplanted， and the longest seedling age did not exceed 30 days. It was suggested that planting density was 20.0 cm×26.7 cm， and planting number was 180 000-195 000 clumps/hm 2. 2 seedlings were planted in each clump， and basic seedlings per hm 2 reached 750 000-900 000. Shallow insertion was advocated， which was conducive to early renascence， and made effective panicle reach 2 250 000-2 700 000 ears/hm 2.
Fertilization management
The variety had strong stem， lodging resistance and higher fertilization level. Fertilization principle of heavy in prior period， light in middle period and supplement in latter period was used， and 210 kg/hm 2 of pure nitrogen was fertilized， and N∶P2O5∶K2O was 1∶0.5∶0.9. More base fertilizer was used， and topdressing should be conducted early， and moderate panicle fertilizer was used. Base fertilizer contained 40% of nitrogen fertilizer and 50% of phosphate fertilizer. Tillering fertilizer was used within 5 days after transplantation， and it contained 20% of nitrogen fertilizer and 50% of phosphorus and potassium fertilizer. In period 4 of young ear differentiation， 45-75 kg/hm 2 of urea and 105-120 kg/hm 2 of potash fertilizer were taken as panicle fertilizer. Water management
In water management， deep water was used to turn green， while shallow water was used for tillering. When total seedling number reached 2 550 000-2 700 000 seedlings/hm 2 （equivalent to final ear number）， field could be dried， and its field drying degree was determined by seedling growth， soil texture and weather situation. Wetness was dominant in early booting stage， and it maintained water layer on field surface in middle and latter periods， and shallow water was maintained in heading period. Humid irrigation was conducted in grouting period， dry and wet， and water was stopped in 7 d before harvest.
Prevention and control of diseases， pests and weeds
Pesticide was used to soak seed to prevent disease. According to disease and insect forecast in field period， it could timely use pesticide to prevent and control banded sclerotial blight， rice blast， snout moths larva and rice planthopper. With 7 days after transplantation， herbicide was used to remove weeds in the field by combining the first topdressing.
Seed production techniques
Correctly arranging sowing and transplanting periods， to ensure florescence encountering
Yuan S was sown in Changsha on May 25， and transplanted on June 12. Initial heading started from August 19， and the duration from sowing to initial heading was 85 d. The duration from sowing of male parent R900 to initial heading was 100 d. Sowing and transplanting periods of summer seed production of Yuanliangyou 900 in Chenzhou of Hunan were as below： time difference was about 15 d， and leaf difference was 6.0 leaves. Male parent was sown on May 1， while sowing period of female parent was on May 16， and heading and flowering stage was during August 10-30.
Rational close planting
Seed use amount of female parent in seed production field was 30 kg/hm 2， and seedling age was 20-23 d. Seed use amount of male parent was 7.5 kg/hm 2， and seedling age was 30 d. Parent line ratio was 2∶（13-14）， and rowing space of female parent used 13.3 cm×16.7 cm. Two grains of rice seedlings were planted， and 345 000-375 000 clumps/hm 2 of basic seedlings were planted. Male parent used large double lines， and rowing space used 16.7 cm×20.0 cm.
Fertilization management
Basic fertilizer of field was dominant by organic fertilizer， and it should use more base fertilizer and early topdressing. Total fertilization amount was converted to 165 kg/hm 2 of pure nitrogen， and the ratio of nitrogen， phosphorus and potash fertilizer was 1∶0.6∶0.8. In 5 days after male parent was cultivated， 151515 of threeelement compound fertilizer （75 kg/hm 2） was used once， to promote tillering. The fertilization method of sufficient base fertilizer and early topdressing was used. 25% of compound fertilizer for rice （600 kg/hm 2） was fertilized when raking field， and 150 kg/hm 2 of urea and potash fertilizer were fertilized in 3 days after planted female parent. In period 5 of young spike differentiation， 45% of compound fertilizer （75 kg/hm 2） and potassium chloride （150 kg/hm 2） were used as panicle fertilizer to improve setting rate. Water management
Shallow water irrigation was dominant. Root lived in inch water， and tillering was conducted by thin water， while field was basked in seedling period. Rehydration was conducted after middle stage of booting period， and 10 cm of water layer was maintained during flowering stage， to decline the influence of high temperature on setting rate. The alternation of dryness and wetness was dominant from latter period of grouting to maturity period， and water was stopped in one week before harvest.
Spraying appropriate amount of "920" in appropriate time
"920" was sprayed twice. "920" was sprayed firstly when 15%-20% of female parent broke， and the usage was 105-120 g/hm 2. When heading reached 40%， the second spraying of "920" was conducted， and the usage was 120-180 g/hm 2. Its cumulative usage was 225-300 g/hm 2.
Strictly removing miscellaneous plant， timely harvesting and ensuring quality
Miscellaneous plants should be strictly removed in whole process of seed production， especially before and after initial heading. It should timely harvest， and prevent mechanical mixing.
Pest control
It should prevent and control grey planthopper in seedling stage， to prevent dwarf. In the field， prevention and control of banded sclerotial blight， smut， rice blast， rice planthopper and rice leaf roller should be conducted. The population of seed production field was large， and the temperature was higher， and seedling was vivid green. Banded sclerotial blight and rice blast should be mainly prevented and controlled. Seedling was sprayed 1-2 times before heading by "Aimiao"， and the usage was 300 ml/hm 2[6].
References
[1] PAN RS， MAO DM， CHEN ZW， et al. Jinshan you 70， a new hybrid rice combination with weak photosensitivity[J]. Hybrid Rice， 2013， 28（1） ： 82-83. （in Chinese）.
[2]YOU Z， LIAO CM. Guangliangyou 2010， a new highyielding twoline hybrid rice combination[J]. Hybrid Rice， 2013， 28（1） ： 83-84 . （in Chinese）.
[3] ZHOU YC， PAN RS， CHEN ZW， et al. Breeding and utilization of a new rice CMS line Jinshan1A with nonchalk， aroma and good quality[J]. Fujian Science and Technology of Rice and Wheat， 2003， 21（1） ： 4-5. （in Chinese）.
[4] ZHANG JX， LIN MJ， WANG XM， et al. Breeding and application of excellentquality and highresistance restorer line Minghui 70[J]. Sanming Agricultural Science and Technology， 2002（1）： 21-25. （in Chinese）.
[5] LV DA， WANG SC， WANG J， et al. Breeding of excellentquality， highyield and midseason hybrid rice Guangliangyou 558[J]. China Seed Industry， 2011（18）：28-29. （in Chinese）.
[6] ZHOU Q， MEI KH， TU JM， et al. Breeding twoline medium hybrid rice variety Guangliangyou 16 with high yield and good quality[J]. Hubei Agricultural Sciences， 2014（14）：3239-3240. （in Chinese）.