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Abstract Xiangzaoyou 2017 is an excellent early maturing variety bred from the combination of Neixiang 3A and the selffertile restorer QN 2017 by Qiannan Institute of Agricultural Sciences of Guizhou Province， and it has been approved by the Guizhou Crop Variety Approval Committee （Approval No.： Qianshendao 2006001）. In order to promote its application in production， the research on the seed production techniques of Xiangzaoyou 2017 was carried out， and the key technical points of highyield seed production of Xiangzaoyou 2017 were put forward.
Key words Threeline hybrid rice; Xiangzaoyou 2017; Seed production technique
The application of selffertile varieties in hybrid rice in Guizhou Province is of great significance to ensure grain yield in Guizhou. Xiangzaoyou 2017 is an excellent earlymaturing variety bred from the combination of the threeline sterile Neixiang 3A and the selffertile restorer QN 2017 of Sichuan Neijiang Hybrid Rice Science and Technology Development Center by Gannan Institute of Agricultural Sciences， Guizhou Province. The combination has strong cold resistance and excellent rice quality （national standard 3 of excellent tastes）. In 2010， it was designated as the control variety for earlymaturing combination in Guizhou Province by Guizhou Crop Variety Approval Committee.
Since it was approved and promoted in 2006， the variety has been very popular among farmers. The seeds of the variety are in short supply every year because of the low seed production yield， which has been a bottleneck restricting the seed supply. In order to improve the seed production of Xiangzaoyou 2017， we went to Guizhou Liping Seed Production Base （with an annual seed production of 120 kg/667m 2 or so） to investigate the factors that restricted the seed production of this variety， finding that the factors mainly included the follows： first， Neixiang 3 A is sensitive to "920" and susceptible to lodging; second， Neixiang 3A is sensitive to temperature during the heading flowering stage， and the activity time of the stigma is shortened when the temperature is too high. On the basis of the test in 2010， in 2011， a largearea highyield seed production test was carried out in Yuping， Guizhou， with a seed production area of 20 hm 2 and an average yield of 262 kg/667 m 2. The highyield production techniques of Neixiang 3A are introduced as follows.
Characteristics of Parents
Female parent Neixiang 3A Neixiang 3A is a variety of early indica rice and has a strong temperature sensitivity. It has a plant height of about 65 cm， compact plant type， upright leaves， thin stems， strong tillering capacity， and it is not tolerant to nitrogen fertilizer and sensitive to "920". In the Yuping Seed Production Base， Neixiang 3A is planted in midMay， and the sowing date is about 72 d. There are 11 leaves in the main stem， and the average number of grains is 112 per ear. The grains are long with the lengthwidth ratio of 3.2∶1， and the grain tip is colorless. Fragrant， the rice has a 1 000grain weight of 28 g， flowering duration per ear of 15 d， big angle of glume opening， and low exposing rate of stigma of about 50%.
Male parent QN 2017
QN 2017 has moderate plant height and strong growth potential. It is planted around March 26 in Yuping Seed Production Base with a sowing date of about 118 d. There are 15 leaves in the main steam， and the plant type is compact. Thick and strong， the stem is tolerant to lodging， but it has weak tillering capacity. The leaves are dark green. The ears are of medium length with an average grain number of 130 per ear. The grains are long and ovate， and the 1 000grain weight is about 32 g. The variety is sensitive to "920".
Highyield Seed Production Technical Points
Selection of highyield seed production base
The seed production base should have an altitude about 500 m with a large temperature difference between day and night. The place should have deep mud fields with good water source， convenient drainage and irrigation， and sufficient sunshine and fertile soil. It should have convenient transportation with large continuous cultivation area， light pests and diseases damage and good isolation conditions. The base should also have local people with experience of seed production techniques.
Arrangement of heading， flowering and pollination periods
The arrangement of the heading pollination period for highyield seed production should follow the principle of avoiding rain but not high temperature. According to the meteorological data analysis of Yuping Base over the years， the average temperature of the Yuping Seed Production Base in July and the middle of July is relatively high， and the rainfall is relatively small， which is the best heading pollination period for the combination.
Determining the sowing gap period of female and male parents to ensure flower synchronization The determination of the sowing gap period of female and male parents should be based on the leaf difference， supplemented by the time difference. In Yuping base， the male parent is planted around March 26， and the female parent is planted around May 12 with a time difference of 47 d and a leaf difference of 7.3 leaves.
Directed cultivation and management of parents super highyield groups
Directed construction of parents super highyield group structure
Cultivating parents seedlings with strong tillering capacity： ① Rice field preparation. The rice field should be the one with fertile soil， convenient drainage and irrigation， low underground water level， exposed to the sun on the lee side and few rats and sparrows. At 14 d before sowing， high quality compost stock manure of 1 000 kg/667 m 2 is applied to the field， and at 3 d before sowing， 50 kg/667m 2 special fertilizer for seed production is applied as the base fertilizer， followed by dividing the rice field into plots and ridging. ② Sparse seeding of strong seedlings. The amount of seed should be consistent with the rice field with male parent of 0.5 kg/667 m 2 （seed amount for big fields）， female parent field seed amount of 4 kg/667 m 2. The ratio of male parents in transplanting field to big field is 1∶10-12， and the ratio of female parent in seedling field to big field is 1∶3. ③ Good strong chlorine disinfection with paclobutrazol dressing. The male parents are performed with accelerating germination in groups， and the seedlings are raised in different households. The female parents are treated in different households. First， the seeds are washed with clean water to remove the sediments， and then the blighted grains are removed， followed by disinfection for 12 h using strong chlorine solution （2 g/kg seeds）. Before germination acceleration， the seeds must be washed with clean water to remove the strong chlorine solution， and the seeds should be exposed more than soaked with constant temperature and moisture to ensure the germination acceleration. After germinated， paclobutrazol is used to dress the seeds. ④ Cultivate strong seedlings. The male parents have the seedlings raised in 2 stages of dry seedling raising and paddy field transplanting. In the first stage， moist seedling raising is adopted to grow nursery bed， and the field should maintain dry， which can be irrigated and drained. The seeds are evenly sown of 0.2 kg/m 2， and when growing into 2.1-2.5 leaves. Transplanting should be avoided in 3leaf period. The transplanting density is 13.3 cm × 13.3 cm， 2-3 seedlings with soil per hole. There are a total of 2 000 clumps/667 m 2. The seedlings are under fine cultivation and management to ensure the average clump of over 15 seedlings. The female parents are cultivated with sparse seedlings of 20 kg/667 m 2. The seedlings should have more than 2 tillers per plant in the 5leaf period. To achieve the above indicators， it is necessary to strengthen the management of fertilizer and water and improve the control of pests and diseases in rice fields. Strengthening field management and timely controlling pests and diseases
① Row ratio， row direction configuration and transplanting specifications. The row direction should be eastwest or perpendicular to the valley wind to improve the utilization of light energy and improve pollen utilization rate. The row ratio is 2∶14， with male parent plant spacing of 33.3 cm male and female parents line spacing of 6.7 cm， female parent planting spacing of 13.3 cm × 13.3 cm. each hole is sown with 4-5 grains. ② Applying enough base fertilizer and controlling the application rate of nitrogen fertilizer. If permitted， 1 000 kg/667 m 2 composted manure is applied to the field at 3-5 d before planting. If there is no farmyard manure， refined fertilizer can be applied before transplanting the female parents. It should act according to the actual circumstances， and the general application amount for seed production is 50 kg/667 m 2. Rice seedling field or the filed applied with farmyard manure should be applied with few fertilizer. The application of nitrogen fertilizer should be strictly controlled in the middle and late stages. ③ Timely transplanting to ensure the transplanting quality. The male parents are transplanted when there are 8.1 leaves， and the female parents are transplanted at 4.5-5.5 leaves. Transplanting of seedlings with exceeding ages should be avoided. The transplanting standard is shallow， upright and straight， with the aim to achieve early germination and lowlevel tillering. The female parents must be transplanted with enough basic seedlings. In short， the principle for the cultivating seedlings of super hybrid groups is that the male parent is dependent on germination but not transplanting while the female parent is dependent on transplanting but not germination. ④ In normal flowering period， the male parents should be topdressed early， and in the middle stages， the seedlings should be supplemented with bract fertilizer. In other words， the male parents are applied with urea， special fertilizer of 10 kg/667 m 2 at 3 d after transplanting deep between parental lines. In the 2-3 ear period of the male parent， 5 kg/667 m 2 each of urea and potassium fertilizer is applied to improve the panicle setting rate， increase the number of spikelets per flower and the amount of pollen， prolong the pollination period， and increase the seed setting rate. The transplanting of female parents should achieve transplanting in deep water. After transplanting， the water should be well managed to achieve no open water in the field. When the highest seedlings of female parent grow to 280 000 – 300 000/667 m 2， ditches are open to drain the water and dry the field. When the ear differentiation reaches the 5 period， the field should be irrigated with water immediately to promote the development of the young ears. In case of drought in the heading flowering period， the filed should be performed with deep water irrigation to increase the filed moisture， lower the temperature of the ear， increase the amount of the male parent pollen and the vitality of the female stigma， promote the flower synchronization of male and female parents， and enhance the fertilization rate. At 5 d before harvesting， the water is drained to dry the field. Shallow sand fields can delay the drainage， so as to increase the 1 000grain weight of the seeds. ⑤ Pest and disease control. After transplanting， the female parents are applied with 45 kg/667 m 2 of carbofuran to control rice straw leaf miner and other insect pests， and in the middle and late periods， attention should be paid to controlling spider mites， panicle neck blight， sheath blight， smut disease. In addition， it should also prevent and control pests such as striped rice borer， leaf tier and rice planthopper[1-2]. Prediction and Regulation of Flowering Period
It should make good observation and record of the leaf age of parents at the fixed point and timing to accurately grasp the growth and development dynamics of the male and female parents. the leaf ages of the male and female parents should be investigated since the 2.5leaf period on the 5th and 10th of every month. It should refer to the development progress of male and female parents of the same periods of the pervious years to find out problems and make timely adjustment. ① Analyzing the weather conditions of the female seeding period. For example， the growth period speed of male parent after sowing should adjust the sowing period of the female parent. ② Paying attention to the weather conditions after the female seeding. If the rooting of female parent is slow after sowing while the growth of male parent is normal， it should adopt timely adjustment to the male parents. ③ Grasping the mediumterm prediction. During the mediumterm growth of male and female parents， the flowering period should be predicted according to the corresponding leaf age method， the young ear microscopic examination method， and the leaf age remainder method. The standard of flowering meeting of the combination in young ear microscopy is as follows： when the male parent is 3 d ahead of time into the young ear differentiation and the female parent ear differentiation begins， the flower synchronization is ideal by applying bract fertilizer to the male parent.
Appropriate Applications of "920"
Spraying period
The application of "920" should adhere to 4 reads， namely， read the field， read the seedlings， read the flowering period， read the weather conditions， to adopt different spraying methods. The general principles are as follows. For the field with heading period of female parent of 3 d earlier or same initial heading period as previous years， the application amount of "920" is 20 g/667 m 2. In other words， when the ears of female parent reach 8%-10%， the female parent is applied with 4 g/667 m 2 Tiaohuabao and 2 g/667 m 2 "920"; when the ears reach 15%-20%， 8 g/667 m 2 "920" is applied to both the male and female parents， and the second application amount is 10 g/667 m 2. If the plant height of male parent is higher than that of the female parent， 2 g/667 m 2 "920" is applied to the male parent only to make the male plant height 20 cm higher than the female parent height. For the field with heading period of male parent over 3 d earlier， when the ears of female parent reach 10%-15%， a total of 20 g/667 m 2 "920" is applied with half the amount each for 2 continuous days， while the male parent is applied with 4 g/667 m 2 "920". The amount should be increased in the case of more seedlings and rainy days. Spraying method
The spraying should be done before 11：00 or after 17：00 in sunny days with high temperature， and all day in cloudy days. In rainy days， it can spray when the rain stops， and if it rains within 4 h after spraying， it should spray again. The spraying should be done evenly in fine mist.
Agricultural Biotechnology2018
Field Mangement
Elimination of Impurities and Inferior Seeds， and Timely Organization of Field Flower Inspection
The elimination of impurities and inferior seeds should be done from the paddy field. During the tillering stage， the heterotypic plants and maintainer lines are removed before and after the initial spike. After the heading， the late maturing abnormal plants in the female parent are thoroughly removed， and the base is organized with twice field identification timely. In other words， the first identification is done before full heading to control the earlymaturing abnormal plants like field maintainer at 0.05%， and the second identification is done in the milkripe period， to control the latematuring abnormal plants at 0.005% and total abnormal plant ratio of less than 0.1%.
Artificial Supplementary Pollination
Pollinating tools
The pollination is performed by using 2 bamboo poles in both directions， and the bamboo pole should of moderate size with the length of about 2 m.
Pollinating time and times
The pollination begins when there are 8-10 flowers per ear of the male parents or most of the ears have flowered every day. The pollination is performed 3 times in the fullbloom period every day， while the pollinating times can be reduced appropriated in the initial flowering and the final flowering period.
Pollinating method
The pollen should flip high and fly far.
Strengthening the Control of Smut and Rotten Necks in Later Period
The smut disease not only causes production reduction， but also affects the appearance quality of seeds. The optimum control period of smut disease is in the initial stage and the milk stage of rice by spraying 4-5 bags/667 m 2 Shimiao， and the control effect can reach more than 90%. . At the same time， isoprothiolane can be applied simultaneously to control rice rotten necks.
Timely Harvest to Prevent Preharvest Sprouting
When the seed maturity reaches 85%， the harvest begins.
The harvest can be delayed in good weather （it can reduce cracked grains）. The harvested seeds should be aired in time， and the seeds can be stored when the water content is below 13% to avoid affecting the seed germination rate.
References
[1] MAO JY. Highyield planting techniques for hybrid rice[J]. Agricultural Technical Services， 2014，6：57-58.
[2] CHEN WH. Highyield planting techniques for the high quality hybrid rice variety Shuangyou 2088[J]. Bulletin of Agricultural Science and Technology， 2016（7）： 204，255.246.
Key words Threeline hybrid rice; Xiangzaoyou 2017; Seed production technique
The application of selffertile varieties in hybrid rice in Guizhou Province is of great significance to ensure grain yield in Guizhou. Xiangzaoyou 2017 is an excellent earlymaturing variety bred from the combination of the threeline sterile Neixiang 3A and the selffertile restorer QN 2017 of Sichuan Neijiang Hybrid Rice Science and Technology Development Center by Gannan Institute of Agricultural Sciences， Guizhou Province. The combination has strong cold resistance and excellent rice quality （national standard 3 of excellent tastes）. In 2010， it was designated as the control variety for earlymaturing combination in Guizhou Province by Guizhou Crop Variety Approval Committee.
Since it was approved and promoted in 2006， the variety has been very popular among farmers. The seeds of the variety are in short supply every year because of the low seed production yield， which has been a bottleneck restricting the seed supply. In order to improve the seed production of Xiangzaoyou 2017， we went to Guizhou Liping Seed Production Base （with an annual seed production of 120 kg/667m 2 or so） to investigate the factors that restricted the seed production of this variety， finding that the factors mainly included the follows： first， Neixiang 3 A is sensitive to "920" and susceptible to lodging; second， Neixiang 3A is sensitive to temperature during the heading flowering stage， and the activity time of the stigma is shortened when the temperature is too high. On the basis of the test in 2010， in 2011， a largearea highyield seed production test was carried out in Yuping， Guizhou， with a seed production area of 20 hm 2 and an average yield of 262 kg/667 m 2. The highyield production techniques of Neixiang 3A are introduced as follows.
Characteristics of Parents
Female parent Neixiang 3A Neixiang 3A is a variety of early indica rice and has a strong temperature sensitivity. It has a plant height of about 65 cm， compact plant type， upright leaves， thin stems， strong tillering capacity， and it is not tolerant to nitrogen fertilizer and sensitive to "920". In the Yuping Seed Production Base， Neixiang 3A is planted in midMay， and the sowing date is about 72 d. There are 11 leaves in the main stem， and the average number of grains is 112 per ear. The grains are long with the lengthwidth ratio of 3.2∶1， and the grain tip is colorless. Fragrant， the rice has a 1 000grain weight of 28 g， flowering duration per ear of 15 d， big angle of glume opening， and low exposing rate of stigma of about 50%.
Male parent QN 2017
QN 2017 has moderate plant height and strong growth potential. It is planted around March 26 in Yuping Seed Production Base with a sowing date of about 118 d. There are 15 leaves in the main steam， and the plant type is compact. Thick and strong， the stem is tolerant to lodging， but it has weak tillering capacity. The leaves are dark green. The ears are of medium length with an average grain number of 130 per ear. The grains are long and ovate， and the 1 000grain weight is about 32 g. The variety is sensitive to "920".
Highyield Seed Production Technical Points
Selection of highyield seed production base
The seed production base should have an altitude about 500 m with a large temperature difference between day and night. The place should have deep mud fields with good water source， convenient drainage and irrigation， and sufficient sunshine and fertile soil. It should have convenient transportation with large continuous cultivation area， light pests and diseases damage and good isolation conditions. The base should also have local people with experience of seed production techniques.
Arrangement of heading， flowering and pollination periods
The arrangement of the heading pollination period for highyield seed production should follow the principle of avoiding rain but not high temperature. According to the meteorological data analysis of Yuping Base over the years， the average temperature of the Yuping Seed Production Base in July and the middle of July is relatively high， and the rainfall is relatively small， which is the best heading pollination period for the combination.
Determining the sowing gap period of female and male parents to ensure flower synchronization The determination of the sowing gap period of female and male parents should be based on the leaf difference， supplemented by the time difference. In Yuping base， the male parent is planted around March 26， and the female parent is planted around May 12 with a time difference of 47 d and a leaf difference of 7.3 leaves.
Directed cultivation and management of parents super highyield groups
Directed construction of parents super highyield group structure
Cultivating parents seedlings with strong tillering capacity： ① Rice field preparation. The rice field should be the one with fertile soil， convenient drainage and irrigation， low underground water level， exposed to the sun on the lee side and few rats and sparrows. At 14 d before sowing， high quality compost stock manure of 1 000 kg/667 m 2 is applied to the field， and at 3 d before sowing， 50 kg/667m 2 special fertilizer for seed production is applied as the base fertilizer， followed by dividing the rice field into plots and ridging. ② Sparse seeding of strong seedlings. The amount of seed should be consistent with the rice field with male parent of 0.5 kg/667 m 2 （seed amount for big fields）， female parent field seed amount of 4 kg/667 m 2. The ratio of male parents in transplanting field to big field is 1∶10-12， and the ratio of female parent in seedling field to big field is 1∶3. ③ Good strong chlorine disinfection with paclobutrazol dressing. The male parents are performed with accelerating germination in groups， and the seedlings are raised in different households. The female parents are treated in different households. First， the seeds are washed with clean water to remove the sediments， and then the blighted grains are removed， followed by disinfection for 12 h using strong chlorine solution （2 g/kg seeds）. Before germination acceleration， the seeds must be washed with clean water to remove the strong chlorine solution， and the seeds should be exposed more than soaked with constant temperature and moisture to ensure the germination acceleration. After germinated， paclobutrazol is used to dress the seeds. ④ Cultivate strong seedlings. The male parents have the seedlings raised in 2 stages of dry seedling raising and paddy field transplanting. In the first stage， moist seedling raising is adopted to grow nursery bed， and the field should maintain dry， which can be irrigated and drained. The seeds are evenly sown of 0.2 kg/m 2， and when growing into 2.1-2.5 leaves. Transplanting should be avoided in 3leaf period. The transplanting density is 13.3 cm × 13.3 cm， 2-3 seedlings with soil per hole. There are a total of 2 000 clumps/667 m 2. The seedlings are under fine cultivation and management to ensure the average clump of over 15 seedlings. The female parents are cultivated with sparse seedlings of 20 kg/667 m 2. The seedlings should have more than 2 tillers per plant in the 5leaf period. To achieve the above indicators， it is necessary to strengthen the management of fertilizer and water and improve the control of pests and diseases in rice fields. Strengthening field management and timely controlling pests and diseases
① Row ratio， row direction configuration and transplanting specifications. The row direction should be eastwest or perpendicular to the valley wind to improve the utilization of light energy and improve pollen utilization rate. The row ratio is 2∶14， with male parent plant spacing of 33.3 cm male and female parents line spacing of 6.7 cm， female parent planting spacing of 13.3 cm × 13.3 cm. each hole is sown with 4-5 grains. ② Applying enough base fertilizer and controlling the application rate of nitrogen fertilizer. If permitted， 1 000 kg/667 m 2 composted manure is applied to the field at 3-5 d before planting. If there is no farmyard manure， refined fertilizer can be applied before transplanting the female parents. It should act according to the actual circumstances， and the general application amount for seed production is 50 kg/667 m 2. Rice seedling field or the filed applied with farmyard manure should be applied with few fertilizer. The application of nitrogen fertilizer should be strictly controlled in the middle and late stages. ③ Timely transplanting to ensure the transplanting quality. The male parents are transplanted when there are 8.1 leaves， and the female parents are transplanted at 4.5-5.5 leaves. Transplanting of seedlings with exceeding ages should be avoided. The transplanting standard is shallow， upright and straight， with the aim to achieve early germination and lowlevel tillering. The female parents must be transplanted with enough basic seedlings. In short， the principle for the cultivating seedlings of super hybrid groups is that the male parent is dependent on germination but not transplanting while the female parent is dependent on transplanting but not germination. ④ In normal flowering period， the male parents should be topdressed early， and in the middle stages， the seedlings should be supplemented with bract fertilizer. In other words， the male parents are applied with urea， special fertilizer of 10 kg/667 m 2 at 3 d after transplanting deep between parental lines. In the 2-3 ear period of the male parent， 5 kg/667 m 2 each of urea and potassium fertilizer is applied to improve the panicle setting rate， increase the number of spikelets per flower and the amount of pollen， prolong the pollination period， and increase the seed setting rate. The transplanting of female parents should achieve transplanting in deep water. After transplanting， the water should be well managed to achieve no open water in the field. When the highest seedlings of female parent grow to 280 000 – 300 000/667 m 2， ditches are open to drain the water and dry the field. When the ear differentiation reaches the 5 period， the field should be irrigated with water immediately to promote the development of the young ears. In case of drought in the heading flowering period， the filed should be performed with deep water irrigation to increase the filed moisture， lower the temperature of the ear， increase the amount of the male parent pollen and the vitality of the female stigma， promote the flower synchronization of male and female parents， and enhance the fertilization rate. At 5 d before harvesting， the water is drained to dry the field. Shallow sand fields can delay the drainage， so as to increase the 1 000grain weight of the seeds. ⑤ Pest and disease control. After transplanting， the female parents are applied with 45 kg/667 m 2 of carbofuran to control rice straw leaf miner and other insect pests， and in the middle and late periods， attention should be paid to controlling spider mites， panicle neck blight， sheath blight， smut disease. In addition， it should also prevent and control pests such as striped rice borer， leaf tier and rice planthopper[1-2]. Prediction and Regulation of Flowering Period
It should make good observation and record of the leaf age of parents at the fixed point and timing to accurately grasp the growth and development dynamics of the male and female parents. the leaf ages of the male and female parents should be investigated since the 2.5leaf period on the 5th and 10th of every month. It should refer to the development progress of male and female parents of the same periods of the pervious years to find out problems and make timely adjustment. ① Analyzing the weather conditions of the female seeding period. For example， the growth period speed of male parent after sowing should adjust the sowing period of the female parent. ② Paying attention to the weather conditions after the female seeding. If the rooting of female parent is slow after sowing while the growth of male parent is normal， it should adopt timely adjustment to the male parents. ③ Grasping the mediumterm prediction. During the mediumterm growth of male and female parents， the flowering period should be predicted according to the corresponding leaf age method， the young ear microscopic examination method， and the leaf age remainder method. The standard of flowering meeting of the combination in young ear microscopy is as follows： when the male parent is 3 d ahead of time into the young ear differentiation and the female parent ear differentiation begins， the flower synchronization is ideal by applying bract fertilizer to the male parent.
Appropriate Applications of "920"
Spraying period
The application of "920" should adhere to 4 reads， namely， read the field， read the seedlings， read the flowering period， read the weather conditions， to adopt different spraying methods. The general principles are as follows. For the field with heading period of female parent of 3 d earlier or same initial heading period as previous years， the application amount of "920" is 20 g/667 m 2. In other words， when the ears of female parent reach 8%-10%， the female parent is applied with 4 g/667 m 2 Tiaohuabao and 2 g/667 m 2 "920"; when the ears reach 15%-20%， 8 g/667 m 2 "920" is applied to both the male and female parents， and the second application amount is 10 g/667 m 2. If the plant height of male parent is higher than that of the female parent， 2 g/667 m 2 "920" is applied to the male parent only to make the male plant height 20 cm higher than the female parent height. For the field with heading period of male parent over 3 d earlier， when the ears of female parent reach 10%-15%， a total of 20 g/667 m 2 "920" is applied with half the amount each for 2 continuous days， while the male parent is applied with 4 g/667 m 2 "920". The amount should be increased in the case of more seedlings and rainy days. Spraying method
The spraying should be done before 11：00 or after 17：00 in sunny days with high temperature， and all day in cloudy days. In rainy days， it can spray when the rain stops， and if it rains within 4 h after spraying， it should spray again. The spraying should be done evenly in fine mist.
Agricultural Biotechnology2018
Field Mangement
Elimination of Impurities and Inferior Seeds， and Timely Organization of Field Flower Inspection
The elimination of impurities and inferior seeds should be done from the paddy field. During the tillering stage， the heterotypic plants and maintainer lines are removed before and after the initial spike. After the heading， the late maturing abnormal plants in the female parent are thoroughly removed， and the base is organized with twice field identification timely. In other words， the first identification is done before full heading to control the earlymaturing abnormal plants like field maintainer at 0.05%， and the second identification is done in the milkripe period， to control the latematuring abnormal plants at 0.005% and total abnormal plant ratio of less than 0.1%.
Artificial Supplementary Pollination
Pollinating tools
The pollination is performed by using 2 bamboo poles in both directions， and the bamboo pole should of moderate size with the length of about 2 m.
Pollinating time and times
The pollination begins when there are 8-10 flowers per ear of the male parents or most of the ears have flowered every day. The pollination is performed 3 times in the fullbloom period every day， while the pollinating times can be reduced appropriated in the initial flowering and the final flowering period.
Pollinating method
The pollen should flip high and fly far.
Strengthening the Control of Smut and Rotten Necks in Later Period
The smut disease not only causes production reduction， but also affects the appearance quality of seeds. The optimum control period of smut disease is in the initial stage and the milk stage of rice by spraying 4-5 bags/667 m 2 Shimiao， and the control effect can reach more than 90%. . At the same time， isoprothiolane can be applied simultaneously to control rice rotten necks.
Timely Harvest to Prevent Preharvest Sprouting
When the seed maturity reaches 85%， the harvest begins.
The harvest can be delayed in good weather （it can reduce cracked grains）. The harvested seeds should be aired in time， and the seeds can be stored when the water content is below 13% to avoid affecting the seed germination rate.
References
[1] MAO JY. Highyield planting techniques for hybrid rice[J]. Agricultural Technical Services， 2014，6：57-58.
[2] CHEN WH. Highyield planting techniques for the high quality hybrid rice variety Shuangyou 2088[J]. Bulletin of Agricultural Science and Technology， 2016（7）： 204，255.246.