The seed setting rates of total 198 rice cultivars （lines） at heading and flowering stage were investigated under the condition of extreme natural high tem- perature in 2013 so as to analyze the effect of extreme na...The seed setting rates of total 198 rice cultivars （lines） at heading and flowering stage were investigated under the condition of extreme natural high tem- perature in 2013 so as to analyze the effect of extreme natural high temperature on seed setting rate of different rice cultivar （line）. The results showed that the contin- uous high temperature showed certain effects on the seed setting rates of tested materials, and significant differences were shown in seed setting rate among differ- ent rice cultivars （lines）. The seed setting rates differed significantly among indica F1 hybrids derived from different sterile and restorer lines, indicating that the sterile and restorer lines had great effects on heat tolerances of different F~ hybrids. The cor- relation analysis showed that the seed setting rates of conventional indica restorer lines and conventional japonica rice cultivars （lines） were negatively related to the daily highest temperature （P〉0.05）, and the seed setting rates of indica F1 hybrids were positively related to the seed setting rates of their restorer lines. Total four in- dica restorer lines, including Ninghuiguangkangzhan, Shuhui 527, Chenghui 3203 and Xianyin-8, and four new japonica rice cultivars （lines）, including Wuyinjinghui （B2）, Nanjing 4//W3660/Nanjing 44 （B12） and Wuyun 2330/JD6011 （B22） were pre- liminarily screened, and their seed setting rates were all close to the normal level （90%）. The screened rice cultivars （lines） showed higher heat tolerances.展开更多
This study aimed to investigate the effects of treatments of rice pollen with different solvents on the seed setting rate.Rice pollen was treated with ultrapure water,0.5%dimethyl sulfoxide,ethanol(1%,5%,and 8%),and 0...This study aimed to investigate the effects of treatments of rice pollen with different solvents on the seed setting rate.Rice pollen was treated with ultrapure water,0.5%dimethyl sulfoxide,ethanol(1%,5%,and 8%),and 0.5%dimethyl sulfoxide+8%ethanol,and the pollen without treatment was taken as the control.Then,crossing was conducted with the treated rice plants as the male parents and plants subjected to emasculation by warm water as the female parents.The seed setting rates of the male and female parents were then recorded.The results showed that the treatments with different solvents significantly decreased the seed setting rates of both male and female parents.The treatment with 1%ethanol resulted in the highest seed setting rates for both male and female parents,while the treatment with 0.5%dimethyl sulfoxide resulted in the lowest seed setting rates for both parents.Although these solvents affected the seed setting rate of rice,they served as intermediate solvents to dissolve chemicals used in the induction of rice haploids.This study layed a technical foundation for subsequent chemical induction of rice haploids.展开更多
When being planted in wide areas in southern China (23°23' - 33°23' N, 98°35' - 120°19' E, sea level above 2.7 - 1285 m), Liangyoupeijiu (LYPJ), a two-line hybrid rice combination, ...When being planted in wide areas in southern China (23°23' - 33°23' N, 98°35' - 120°19' E, sea level above 2.7 - 1285 m), Liangyoupeijiu (LYPJ), a two-line hybrid rice combination, showed a seed setting rate of 75.2 - 77.2%, which was lower by 4.3 - 7.5 percent point than that of an indica hybrid rice Shanyou 63 (CK), with similar values of grain yield and coefficients of variation to CK. Sowing during 5-25th of May in Nanjing (32°3' N, 118°48' E), China, LYPJ headed before 4th September, and gave a seed setting rate of 75 - 90%, and grain yield over 1 kg/m2. If the sowing date was delayed to 14 - 15th, June, its heading date would be as late as 17th - 21st September, and seed setting rate would be declined by 10 - 15% in comparison with that on a suitable sowing date. When flowering took place at an average daily temperature range of 13.7 - 28.5℃ for five days, the spikelet fertility (SF) would be increased by 1.9- 10.7%, for each increment of 1℃. The suitable (SF≥90%) and safe (SF≥75%) temperatures for flowering stage were indicated to be 26.5℃ and 22.9℃, respectively. To get a high and stable seed set in cultivating LYPJ, it was recommended that LYPJ would be planted in the areas south of 34癗, and the favorable average daily temperature during flowering stage should be at 26 - 28℃.展开更多
Using photo-thermo sensitive genie male rice (PTGMS) Pei' ai 64S, W7415S, W6154S, N26S, Annong S, Nongken 58S, 7001S and 5088S as female parents and conventional indica lines 8258 and U89 as male parents, the fact...Using photo-thermo sensitive genie male rice (PTGMS) Pei' ai 64S, W7415S, W6154S, N26S, Annong S, Nongken 58S, 7001S and 5088S as female parents and conventional indica lines 8258 and U89 as male parents, the factors affecting outcrossed seed-setting were analyzed. The PTGMS had obstacles in outcrossed seed setting influenced by inheritance and environment at varying degrees. Environmental temperature was regarded as the main factor that resulted in the outcrossed seed-setting obstacles. The sensitive stage was at the early stage of grain filling for outcrossed seed setting. There existed remarkable differences at the sensitivity stage, the duration of sensitive period, the sensitive level and the effective level of outcrossed seed-setting obstacles caused by environmental temperature among different PTGMS lines. Therefore, attention should be paid to outcrossed seed-setting obstacles in selection and utilization of PTGMS lines.展开更多
[Objective] The paper was to explore the flowering habits and fertility of Gaozhou common wild rice （Oryza rufipogon Griff.） in Lingshui of Hainan Province. [Method] The flowering habits, pollen fertility and seed s...[Objective] The paper was to explore the flowering habits and fertility of Gaozhou common wild rice （Oryza rufipogon Griff.） in Lingshui of Hainan Province. [Method] The flowering habits, pollen fertility and seed setting rate of Gaozhou common wild rice in Lingshui of Hainan Province were studied, and compared with the flowering habits of common wild rice in Hainan Province. [Result] Gaozhou common wild rice was able to flower twice a year. The first flowering stage was from mid-April to mid-June for about 60 d, and the daily peak flowering dates were from May 13 to May 22. The daily flowering time was mainly between 11：20 and 13：00, and the peak flowering was at 11：30. The second flowering stage was from late August to late October for about 45 d, and the peak flowering dates lasted from September 8 to September 18. The daily flowering time was mainly from 11：15 to 12：50, and the daily peak flowering was at 11：30. In both flowering stages, the panicles had the same flowering characteristics. The stigma exsertion reached a high value of 95.37% with single （46.23%） and dual （49.14%） stigmas exsertion respectively. A spikelet remained open for 1.5-2.5 h, the angle of spikelet opening varied from 29.9° to 32.4°. At the two flowering stage the average pollen fertility rates were 89.67% and 85.62%, the average seed setting rates were 58.81% and 55.79%, respectively. Hainan population flowered only once （from mid-October to mid-December）, this had significant difference with the performance of Gaozhou common wild rice which flowered twice a year. [Conclusion] The results provided basis for the research on gene flow frequency from transgenic rice to wild rice and its relationship with flowering habits of common wild rice.展开更多
The structures of mature embryo sacs in 13 genetic stock lines of autotetraploid rice （Oryza sativa L.）, including indica, japonica and javanica, were studied by using the whole-mount stain-clearing laser scanning c...The structures of mature embryo sacs in 13 genetic stock lines of autotetraploid rice （Oryza sativa L.）, including indica, japonica and javanica, were studied by using the whole-mount stain-clearing laser scanning confocal microscopy （WCLSM）. Among the 13 autotetraploid rice, the majority of ovaries possess normal polygonum-type embryo sacs, while a few ovaries were characterized by abnormal embryo sacs. The abnormalities of embryo sacs could be classified into six categories, i. e. no female germ unit, abnormal polar nuclei, embryo sac degeneration, no egg apparatus, small embryo sac and ＇double set＇ of embryo sacs. The frequency of abnormal embryo sac in japonica （26.6%） was higher than that in indica （19.34%）. In addition, the major abnormalities in each autotetraploid line varied, suggesting that the abnormalities may be related to the genotypes of the varieties.展开更多
The germination of pollen grain in vitro and the growth of pollen tube in the pistil of rice were observed with a microscope. The stigma was removed at different time points after pollination to study its effect on se...The germination of pollen grain in vitro and the growth of pollen tube in the pistil of rice were observed with a microscope. The stigma was removed at different time points after pollination to study its effect on seed setting rate. The rice pollen grain started to germinate at 2 min after pollination and the pollen tube penetrated stigma into style in 5-10 min, 30 min later the end of pollen tube reached the bottom of ovary, and only some pollen tubes arrived at embryo sac at 40 min after pollination. Meanwhile, a small amount of callose began to deposit in the pollen tubes, a great deal of callose was observed at 50 min after pollination, whereas the pollen grain began to shrink. The growing rates of pollen tube in the rice stigma, style and ovary were 1500, 5000, and 5400 μm/h, respectively. The seed setting rate was quite low when the stigma was removed at about 10-15 min after pollination, gradually increased when it removed at 20 min to 50 min after pollination, and over 60% when it removed at 50 min after pollination and finally tended to be stable.展开更多
Comparison of seed setting rate,plant height and Cheng's morphological traits were made between the F_(2)progeny of indica-japonica hybrids,02428/Pei'ai 64 and Taichung 65/Teqing.There existed resemblance norm...Comparison of seed setting rate,plant height and Cheng's morphological traits were made between the F_(2)progeny of indica-japonica hybrids,02428/Pei'ai 64 and Taichung 65/Teqing.There existed resemblance normal distribution in plant height,and the distribution had no relationship with the seed setting rate and plant height in F_(1)progeny,suggesting that there were no gametic selection for the plant height in the F_(2)progeny of indica-japoniea hybrids.An average seed setting rate of the F_(2)was equal to the F_(1)populations in the recombination of 02428/Pei'ai 64 in which there was an excellent cross compatibility,but the remarkable increase in the seed setting rate from the F_(1)to F_(2)in Taichung 65/Teqing,indicating that gametic selection only took place in the indica-japonica crosses with low cross compatibility while null or little in the hybrids with high compatibility.There were many intermediate types among the leaf pubescence,color of hull at heading,and length of the first and second panicle internode,and these Cheng's morphological traits was distributed normally;there were also a little intermediate types in hull hairness and phenol reaction with bi-peak distribution;while length to width ratio of grain was inclined to the japonica types obviously showing a skewed distribution in the F_(2)population.Although Cheng's morphological traits in F_(2)populations had inconsistent distribution types,Cheng's morphological traits index showed normal distribution,which suggested that intermediate types,i.e.indicalinous or japonicalinous,were primary in F_(2)population.展开更多
Based on a series of polyploid indica-japonica hybrid plant lines obtained from a new breeding strategy of using double predominance of wide cross and polyploidization to breed super flee, two polyploid indica-japonic...Based on a series of polyploid indica-japonica hybrid plant lines obtained from a new breeding strategy of using double predominance of wide cross and polyploidization to breed super flee, two polyploid indica-japonica hybrids, PSR073 and PSR120 were studied in their growth periods to show the powerful heterosis in a larger scale and to study the characteristics of polyploid indica-japonica hybrids more elaborately. The leaf age, tiller growth, flowering habits, and agronomic traits of them were observed to analyze their growth habits and characteristics. The results showed that the.agronomic traits of PSR073 and PSR120, such as the plant height, panicle length, grain length, grain width, and 1000-grain weight, all acquired obvious predominance of polyploidy, and that the seed setting rate was more than 83%. No significant difference was observed between the two tetraploids and common diploids in the leaf age, tiller growth, and flowering habits. It was concluded that the characteristics of the two powerful heterosis polyploid hybrids were different from those of the polyploid rice reported earlier. Wide cross and polyploidization had no negative effects on their growth habits and characteristics; on the contrary these had powerful heterosis. This had provided theoretic and practical evidences for their application to agricultural production.展开更多
Polyploidization is a basic feature of plant evolution.Nearly all of the main food,cotton and oil crops are polyploid.When ploidy levels increase,yields double;this phenomenon suggested a new strategy of rice breeding...Polyploidization is a basic feature of plant evolution.Nearly all of the main food,cotton and oil crops are polyploid.When ploidy levels increase,yields double;this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice.Because low seed set rates in polyploid rice usually makes it difficult to breed,the selection of Ph-liked gene lines was emphasized.After progenies of indica-japonica were identified and selected,two poly-ploid lines,PMeS-1 and PMeS-2 with Polyploid Meiosis Stability(PMeS)genes were bred.The proce-dure included seven steps:selecting parents,crossing or multiple crossing,back-crossing,doubling chromosomes,identifying the polyploid,and choosing plants with high seed set rates that can breed themselves into stable lines.The characteristics of PMeS were determined by observing meiotic be-haviors and by cross-identification of seed sets.PMeS-1 and PMeS-2,(japonica rice),have several characteristics different from other polyploid rice lines,including a higher rate of seed set(more than 65%,increasing to more than 70%in their F1 offspring);and stable meiotic behaviors(pairing with bi-valents and quarivalents nearly without over-quarivalent in prophase,nearly without lagging chromo-somes in metaphase and without micronuclei in anaphase and telophase).The latter was obviously different from control polyploid line Dure-4X,which displayed abnormal meiotic behaviors including a higher rate of multivalents,univalents and trivalents in prophase,lagging chromosomes in metaphase and micronuclei in anaphase and telophase.There were also three differences of the breeding method between PMeS lines and normal diploid lines:chromosomes doubling,polyploidism identifying and higher seed set testing.The selection of PMeS lines is the first step in polyploid rice breeding;their use will advance the progress of polyploid rice breeding,which will in turn offer a new way to breed super rice.展开更多
Double haploid(DH)technology can significantly shorten the breeding cycle and improve the breeding effi-ciency,and it is favored by breeders.The metrics for evaluating the effect of haploid genome doubling mainly incl...Double haploid(DH)technology can significantly shorten the breeding cycle and improve the breeding effi-ciency,and it is favored by breeders.The metrics for evaluating the effect of haploid genome doubling mainly include anther emergence and ear seed setting.The evaluation of fertility restoration ability is mainly conducted through visual inspection at present,which is time-consuming,and easy to be affected by fatigue,resulting in errors and inconsistencies.Therefore,it is urgent to develop efficient and accurate evaluation technology to reduce the field work burden of researchers.In this work,we propose a grading evaluation model(Maize-IRNet)of haploid anther emergence and ear seed setting based on Inception-ResNet.Firstly,the modules of Stem and Inception-ResNet are utilized for image feature extraction and multi-scale feature learning.Then,the Reduction module is used for spatial downsampling and feature compression,and the global attention mechanism(GAM)is used to enhance the recognition of key regions of the image.The experimental results show that the Maize-IRNet's classification accuracy of haploid ear seed setting and anther emergence is 84.2%and 84.0%,which is higher than six baseline methods(VGG11_bn,ResNet50,ResNet101,ViT-Base-16,gMLP,MLP-Mixer).In order to facilitate the practical application for breeding researchers,we have developed a mobile application that in-tegrates the Maize-IRNet model.This study helps to achieve high-throughput collection of fertility restoration phenotypes,improves the evaluation efficiency of fertility restoration,reduces breeding costs,and provides technical support for the promotion of engineering breeding of DH technology.展开更多
基金Supported by National Natural Science Foundation of China(31201181)Earmarked Fund for China Agriculture Research System(CARS-01-47)Project for Breeding and Demonstration of New Super Rice Varieties~~
文摘The seed setting rates of total 198 rice cultivars （lines） at heading and flowering stage were investigated under the condition of extreme natural high tem- perature in 2013 so as to analyze the effect of extreme natural high temperature on seed setting rate of different rice cultivar （line）. The results showed that the contin- uous high temperature showed certain effects on the seed setting rates of tested materials, and significant differences were shown in seed setting rate among differ- ent rice cultivars （lines）. The seed setting rates differed significantly among indica F1 hybrids derived from different sterile and restorer lines, indicating that the sterile and restorer lines had great effects on heat tolerances of different F~ hybrids. The cor- relation analysis showed that the seed setting rates of conventional indica restorer lines and conventional japonica rice cultivars （lines） were negatively related to the daily highest temperature （P〉0.05）, and the seed setting rates of indica F1 hybrids were positively related to the seed setting rates of their restorer lines. Total four in- dica restorer lines, including Ninghuiguangkangzhan, Shuhui 527, Chenghui 3203 and Xianyin-8, and four new japonica rice cultivars （lines）, including Wuyinjinghui （B2）, Nanjing 4//W3660/Nanjing 44 （B12） and Wuyun 2330/JD6011 （B22） were pre- liminarily screened, and their seed setting rates were all close to the normal level （90%）. The screened rice cultivars （lines） showed higher heat tolerances.
基金Supported by Agricultural Science and Technology Innovation Fund Project of Hunan Province(2023-CX17)Yuelushan Seed Industry Innovation Project of Hunan Innovation Province Construction Special Project(2021NK1012)。
文摘This study aimed to investigate the effects of treatments of rice pollen with different solvents on the seed setting rate.Rice pollen was treated with ultrapure water,0.5%dimethyl sulfoxide,ethanol(1%,5%,and 8%),and 0.5%dimethyl sulfoxide+8%ethanol,and the pollen without treatment was taken as the control.Then,crossing was conducted with the treated rice plants as the male parents and plants subjected to emasculation by warm water as the female parents.The seed setting rates of the male and female parents were then recorded.The results showed that the treatments with different solvents significantly decreased the seed setting rates of both male and female parents.The treatment with 1%ethanol resulted in the highest seed setting rates for both male and female parents,while the treatment with 0.5%dimethyl sulfoxide resulted in the lowest seed setting rates for both parents.Although these solvents affected the seed setting rate of rice,they served as intermediate solvents to dissolve chemicals used in the induction of rice haploids.This study layed a technical foundation for subsequent chemical induction of rice haploids.
文摘When being planted in wide areas in southern China (23°23' - 33°23' N, 98°35' - 120°19' E, sea level above 2.7 - 1285 m), Liangyoupeijiu (LYPJ), a two-line hybrid rice combination, showed a seed setting rate of 75.2 - 77.2%, which was lower by 4.3 - 7.5 percent point than that of an indica hybrid rice Shanyou 63 (CK), with similar values of grain yield and coefficients of variation to CK. Sowing during 5-25th of May in Nanjing (32°3' N, 118°48' E), China, LYPJ headed before 4th September, and gave a seed setting rate of 75 - 90%, and grain yield over 1 kg/m2. If the sowing date was delayed to 14 - 15th, June, its heading date would be as late as 17th - 21st September, and seed setting rate would be declined by 10 - 15% in comparison with that on a suitable sowing date. When flowering took place at an average daily temperature range of 13.7 - 28.5℃ for five days, the spikelet fertility (SF) would be increased by 1.9- 10.7%, for each increment of 1℃. The suitable (SF≥90%) and safe (SF≥75%) temperatures for flowering stage were indicated to be 26.5℃ and 22.9℃, respectively. To get a high and stable seed set in cultivating LYPJ, it was recommended that LYPJ would be planted in the areas south of 34癗, and the favorable average daily temperature during flowering stage should be at 26 - 28℃.
文摘Using photo-thermo sensitive genie male rice (PTGMS) Pei' ai 64S, W7415S, W6154S, N26S, Annong S, Nongken 58S, 7001S and 5088S as female parents and conventional indica lines 8258 and U89 as male parents, the factors affecting outcrossed seed-setting were analyzed. The PTGMS had obstacles in outcrossed seed setting influenced by inheritance and environment at varying degrees. Environmental temperature was regarded as the main factor that resulted in the outcrossed seed-setting obstacles. The sensitive stage was at the early stage of grain filling for outcrossed seed setting. There existed remarkable differences at the sensitivity stage, the duration of sensitive period, the sensitive level and the effective level of outcrossed seed-setting obstacles caused by environmental temperature among different PTGMS lines. Therefore, attention should be paid to outcrossed seed-setting obstacles in selection and utilization of PTGMS lines.
基金Supported by Special Project of GM(2009ZX08011-010B,2008XZ08011-011)~~
文摘[Objective] The paper was to explore the flowering habits and fertility of Gaozhou common wild rice （Oryza rufipogon Griff.） in Lingshui of Hainan Province. [Method] The flowering habits, pollen fertility and seed setting rate of Gaozhou common wild rice in Lingshui of Hainan Province were studied, and compared with the flowering habits of common wild rice in Hainan Province. [Result] Gaozhou common wild rice was able to flower twice a year. The first flowering stage was from mid-April to mid-June for about 60 d, and the daily peak flowering dates were from May 13 to May 22. The daily flowering time was mainly between 11：20 and 13：00, and the peak flowering was at 11：30. The second flowering stage was from late August to late October for about 45 d, and the peak flowering dates lasted from September 8 to September 18. The daily flowering time was mainly from 11：15 to 12：50, and the daily peak flowering was at 11：30. In both flowering stages, the panicles had the same flowering characteristics. The stigma exsertion reached a high value of 95.37% with single （46.23%） and dual （49.14%） stigmas exsertion respectively. A spikelet remained open for 1.5-2.5 h, the angle of spikelet opening varied from 29.9° to 32.4°. At the two flowering stage the average pollen fertility rates were 89.67% and 85.62%, the average seed setting rates were 58.81% and 55.79%, respectively. Hainan population flowered only once （from mid-October to mid-December）, this had significant difference with the performance of Gaozhou common wild rice which flowered twice a year. [Conclusion] The results provided basis for the research on gene flow frequency from transgenic rice to wild rice and its relationship with flowering habits of common wild rice.
基金supported by the National Natural Science Foundations of China(Grant No.30270814)the Teaching and Research Award Program for 0utstanding Young Teachers in Higher Education Institutions of M0E,P.R.China.
文摘The structures of mature embryo sacs in 13 genetic stock lines of autotetraploid rice （Oryza sativa L.）, including indica, japonica and javanica, were studied by using the whole-mount stain-clearing laser scanning confocal microscopy （WCLSM）. Among the 13 autotetraploid rice, the majority of ovaries possess normal polygonum-type embryo sacs, while a few ovaries were characterized by abnormal embryo sacs. The abnormalities of embryo sacs could be classified into six categories, i. e. no female germ unit, abnormal polar nuclei, embryo sac degeneration, no egg apparatus, small embryo sac and ＇double set＇ of embryo sacs. The frequency of abnormal embryo sac in japonica （26.6%） was higher than that in indica （19.34%）. In addition, the major abnormalities in each autotetraploid line varied, suggesting that the abnormalities may be related to the genotypes of the varieties.
基金the National Natural Science Foundation of China (Grants Nos. 30070454 and 30471045)
文摘The germination of pollen grain in vitro and the growth of pollen tube in the pistil of rice were observed with a microscope. The stigma was removed at different time points after pollination to study its effect on seed setting rate. The rice pollen grain started to germinate at 2 min after pollination and the pollen tube penetrated stigma into style in 5-10 min, 30 min later the end of pollen tube reached the bottom of ovary, and only some pollen tubes arrived at embryo sac at 40 min after pollination. Meanwhile, a small amount of callose began to deposit in the pollen tubes, a great deal of callose was observed at 50 min after pollination, whereas the pollen grain began to shrink. The growing rates of pollen tube in the rice stigma, style and ovary were 1500, 5000, and 5400 μm/h, respectively. The seed setting rate was quite low when the stigma was removed at about 10-15 min after pollination, gradually increased when it removed at 20 min to 50 min after pollination, and over 60% when it removed at 50 min after pollination and finally tended to be stable.
基金supported by a grant from the Department of Science and Technique and Education in Hubei Province(2000B05006 and 2001 AA204A01)the 9th Key Pro-jects of Chinese Academy of Sciences(KY951A13029).
文摘Comparison of seed setting rate,plant height and Cheng's morphological traits were made between the F_(2)progeny of indica-japonica hybrids,02428/Pei'ai 64 and Taichung 65/Teqing.There existed resemblance normal distribution in plant height,and the distribution had no relationship with the seed setting rate and plant height in F_(1)progeny,suggesting that there were no gametic selection for the plant height in the F_(2)progeny of indica-japoniea hybrids.An average seed setting rate of the F_(2)was equal to the F_(1)populations in the recombination of 02428/Pei'ai 64 in which there was an excellent cross compatibility,but the remarkable increase in the seed setting rate from the F_(1)to F_(2)in Taichung 65/Teqing,indicating that gametic selection only took place in the indica-japonica crosses with low cross compatibility while null or little in the hybrids with high compatibility.There were many intermediate types among the leaf pubescence,color of hull at heading,and length of the first and second panicle internode,and these Cheng's morphological traits was distributed normally;there were also a little intermediate types in hull hairness and phenol reaction with bi-peak distribution;while length to width ratio of grain was inclined to the japonica types obviously showing a skewed distribution in the F_(2)population.Although Cheng's morphological traits in F_(2)populations had inconsistent distribution types,Cheng's morphological traits index showed normal distribution,which suggested that intermediate types,i.e.indicalinous or japonicalinous,were primary in F_(2)population.
文摘Based on a series of polyploid indica-japonica hybrid plant lines obtained from a new breeding strategy of using double predominance of wide cross and polyploidization to breed super flee, two polyploid indica-japonica hybrids, PSR073 and PSR120 were studied in their growth periods to show the powerful heterosis in a larger scale and to study the characteristics of polyploid indica-japonica hybrids more elaborately. The leaf age, tiller growth, flowering habits, and agronomic traits of them were observed to analyze their growth habits and characteristics. The results showed that the.agronomic traits of PSR073 and PSR120, such as the plant height, panicle length, grain length, grain width, and 1000-grain weight, all acquired obvious predominance of polyploidy, and that the seed setting rate was more than 83%. No significant difference was observed between the two tetraploids and common diploids in the leaf age, tiller growth, and flowering habits. It was concluded that the characteristics of the two powerful heterosis polyploid hybrids were different from those of the polyploid rice reported earlier. Wide cross and polyploidization had no negative effects on their growth habits and characteristics; on the contrary these had powerful heterosis. This had provided theoretic and practical evidences for their application to agricultural production.
基金the National Natural Science Foundation of China(Grant Nos.39970447,30240090,30471063 and 30650002)the High Technology Research and Development Program of China(Grant No.SZ-01-02-02)+1 种基金the Chenguang Youth Science and Technology Project of Wuhan City(Grant No.20045006071-31)the Educational Commission of Hubei Province of China(Grant No.2004D004)
文摘Polyploidization is a basic feature of plant evolution.Nearly all of the main food,cotton and oil crops are polyploid.When ploidy levels increase,yields double;this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice.Because low seed set rates in polyploid rice usually makes it difficult to breed,the selection of Ph-liked gene lines was emphasized.After progenies of indica-japonica were identified and selected,two poly-ploid lines,PMeS-1 and PMeS-2 with Polyploid Meiosis Stability(PMeS)genes were bred.The proce-dure included seven steps:selecting parents,crossing or multiple crossing,back-crossing,doubling chromosomes,identifying the polyploid,and choosing plants with high seed set rates that can breed themselves into stable lines.The characteristics of PMeS were determined by observing meiotic be-haviors and by cross-identification of seed sets.PMeS-1 and PMeS-2,(japonica rice),have several characteristics different from other polyploid rice lines,including a higher rate of seed set(more than 65%,increasing to more than 70%in their F1 offspring);and stable meiotic behaviors(pairing with bi-valents and quarivalents nearly without over-quarivalent in prophase,nearly without lagging chromo-somes in metaphase and without micronuclei in anaphase and telophase).The latter was obviously different from control polyploid line Dure-4X,which displayed abnormal meiotic behaviors including a higher rate of multivalents,univalents and trivalents in prophase,lagging chromosomes in metaphase and micronuclei in anaphase and telophase.There were also three differences of the breeding method between PMeS lines and normal diploid lines:chromosomes doubling,polyploidism identifying and higher seed set testing.The selection of PMeS lines is the first step in polyploid rice breeding;their use will advance the progress of polyploid rice breeding,which will in turn offer a new way to breed super rice.
基金supported by the National Key Research and Development Program of China[2022YFD1201504]National Natural Science Foundation of China[32572406]+3 种基金Major Program(JD)of Hubei Province[2025BEA003]Hubei Provincial Natural Science Foundation[2023AFB832]Guizhou Provincial Basic Research Program(Natural Science)[MS[2025]096]Major Project of Hubei Hongshan Laboratory[2022H SZD031].
文摘Double haploid(DH)technology can significantly shorten the breeding cycle and improve the breeding effi-ciency,and it is favored by breeders.The metrics for evaluating the effect of haploid genome doubling mainly include anther emergence and ear seed setting.The evaluation of fertility restoration ability is mainly conducted through visual inspection at present,which is time-consuming,and easy to be affected by fatigue,resulting in errors and inconsistencies.Therefore,it is urgent to develop efficient and accurate evaluation technology to reduce the field work burden of researchers.In this work,we propose a grading evaluation model(Maize-IRNet)of haploid anther emergence and ear seed setting based on Inception-ResNet.Firstly,the modules of Stem and Inception-ResNet are utilized for image feature extraction and multi-scale feature learning.Then,the Reduction module is used for spatial downsampling and feature compression,and the global attention mechanism(GAM)is used to enhance the recognition of key regions of the image.The experimental results show that the Maize-IRNet's classification accuracy of haploid ear seed setting and anther emergence is 84.2%and 84.0%,which is higher than six baseline methods(VGG11_bn,ResNet50,ResNet101,ViT-Base-16,gMLP,MLP-Mixer).In order to facilitate the practical application for breeding researchers,we have developed a mobile application that in-tegrates the Maize-IRNet model.This study helps to achieve high-throughput collection of fertility restoration phenotypes,improves the evaluation efficiency of fertility restoration,reduces breeding costs,and provides technical support for the promotion of engineering breeding of DH technology.
