[Objective] To breed and utilize the japonicalinous cytoplasmic male sterile （CMS） line Chunjiang 19A with wide compatibility and high outcrossing rate. [Method] Cbunjiang 16A was used as the female parent to cross ...[Objective] To breed and utilize the japonicalinous cytoplasmic male sterile （CMS） line Chunjiang 19A with wide compatibility and high outcrossing rate. [Method] Cbunjiang 16A was used as the female parent to cross with Indica-Japonica crossing material B125, which was used as male parent. Backcross breeding was contin- ued for consecutive generations to breed the CMS lines with wide compatibility and high outcrossing rate. [Result] Chunjiang 19A is a late medium Japonica CMS line with good fertility stability. The proportion of sterile plants and pollen abortion rates are 100% and the Cheng＇s index is 14. It is the japonicalinous CMS line with early flowering, partial stigma exsertion, high outcrossing rate, wide compatibility, high re- sistance to stripe disease and good combining ability. The hybrid rice combinations originated from Chunjiang 19A have strong tUlering ability, dominant heterosis, high resistance to stripe disease, great yield potential and good color change at mature stage. [Conclusion] The successful breeding of Chunjiang 19A laid good foundation for the breeding of Japonica hybrid rice and Indica-Japonica hybrid rice combinations with high seed production and dominant heterosis, showing a promising application prospect.展开更多
Longfeng A, derived from the cross of Bo A/（Zhenshan 97B/Bo B F1//Bo B/Gui 2 F1）, is a new high-quality indica CMS line with soft-grain characteristics in cooking rice. The CMS line is characterized by good agronomi...Longfeng A, derived from the cross of Bo A/（Zhenshan 97B/Bo B F1//Bo B/Gui 2 F1）, is a new high-quality indica CMS line with soft-grain characteristics in cooking rice. The CMS line is characterized by good agronomic traits, complete pol en sterility, stale fertility, favorable outcrossing habits, high combining ability and good grain quality. It was technical y identified by Guangxi Crop Variety Appraisal Committee in June, 2013.展开更多
[Objective] Understanding the photosynthetic characteristics of the rice CMS line Renong 1A with leaf color markers can promote its utilization in breeding. [Method] The wild type （WT） of rice spontaneous mutant wit...[Objective] Understanding the photosynthetic characteristics of the rice CMS line Renong 1A with leaf color markers can promote its utilization in breeding. [Method] The wild type （WT） of rice spontaneous mutant with virescent-yellow leaves that was the male parent of Renong 1A was selected as the control, and the contents of photosynthetic pigments, photosynthetic parameters, light-response curve and chlorophyll fluorescence kinetic parameters of Renong 1A were measured at the tillering stage. [Result] New leaves of Renong 1A yellowed obviously in the early period. Chlorophyll content, photosynthetic rate and values of parameters Pdt, F/Fm Fv＇/Fm＇,φPSII, and ETR of Renong 1A were all significantly lower than those of the control. However, there was no difference between Renong 1A and the control in terms of photosynthetic rate of leaves turning green. [Conclusion] The photosynthetic capacity of new leaves of Renong 1A decreased at the early stage due to the reduction of chlorophyll content, and then it became normal at the later stage with the increase of chlorophyll content.展开更多
Ningxian 2A is a new Indica CMS line with WA type sterile cytoplasm in rice. It was developed from the testcross between WA type indica CMS line Jin 23A and the single plant selected from the F_4 population of the cro...Ningxian 2A is a new Indica CMS line with WA type sterile cytoplasm in rice. It was developed from the testcross between WA type indica CMS line Jin 23A and the single plant selected from the F_4 population of the cross Wuxiang 2B×Jin 23B followed by successive backcross over years. In September, 2014, it was technically identified by Jiangsu Provincial Crop Variety Appraisal Committee. Ningxian 2A has the characteristics of complete pollen sterility, high outcrossing rate, good plant type, high combining ability and good grain quality. Among its hybrids, Ningxian you 8（ Ningxian 2A×R08） was registered and released for commercial production in Jiangsu Province in May, 2015.展开更多
Renong 1Ais a new indica CMS line with leaf color marker, developed by testcrossing and continuous backcrossing, using a spontaneous mutant with vires-cent-yel ow leaf isolated from the progenies of T98B /Jin 23B ...Renong 1Ais a new indica CMS line with leaf color marker, developed by testcrossing and continuous backcrossing, using a spontaneous mutant with vires-cent-yel ow leaf isolated from the progenies of T98B /Jin 23B ×Yixiang 1B as the male parent, and Fengyuan A as the female parent. Al the chlorotic leaves of Renong 1A turn green in later developmental stages from leaf tip to base. This is the reason why Renong 1A is a new ideal leaf color marker material in indica rice. It shows apparent and stable leaf marker trait, good agronomic traits, high outcross-ing rate, complete pol en sterility, fine grain quality and high combining ability. Renong 1A has already been technical y identified and certified by Hainan Provincial Crop Variety Appraisal Committee in 2013.展开更多
Yangfujing 7A, derived from the cross between Xu 9201A and Yangfujing 7 and its successive backcrosses, is a BT-type japonica CMS line developed by the Agricultural Institute of Riparian Region of Jiangsu Province. It...Yangfujing 7A, derived from the cross between Xu 9201A and Yangfujing 7 and its successive backcrosses, is a BT-type japonica CMS line developed by the Agricultural Institute of Riparian Region of Jiangsu Province. It shows good integrat- ed characteristics, stable male sterility, good flowering habits, high out crossing rate, strong disease resistance, fine grain quality （reaching the 1st class of national standards for fine quality rice） and high combining ability. In 2012, it was technically identified in Jiangsu Province. Its F1 hybrid combination Tongyoujingl （Yangfujing 7 A/R98）, showing high yield and good grain quality, was registered and released to commercial production by Jiangsu Crop Variety Appraisal Committee in 2013.展开更多
Xinlong A was a high quality indica CMS line developed with early rice intermediate material 05Zao20(Zhouyou 903/Zhong9B F6)as female parent and IR58025B/Q96 F4 as male parent,Jin23A was then used as female parent for...Xinlong A was a high quality indica CMS line developed with early rice intermediate material 05Zao20(Zhouyou 903/Zhong9B F6)as female parent and IR58025B/Q96 F4 as male parent,Jin23A was then used as female parent for test crossing with BC,and backcrossed and bred with complete fertility and abortion lines.The male sterile line had the characteristics of good agronomic characters,strong combining ability,good resistance,high yield and good quality which reaches gradeⅡstandard of national high quality rice.It showed broad prospects and was technically identified in Jiangxi Province in 2017.展开更多
From the view of methodology for genetic improvement ofJaponicacytoplasmic male sterile(CMS) lines,we introduced the breeding process of the dwarf-abortive type(DA type)JaponicaCMS line Chunjiang 95A with wide compati...From the view of methodology for genetic improvement ofJaponicacytoplasmic male sterile(CMS) lines,we introduced the breeding process of the dwarf-abortive type(DA type)JaponicaCMS line Chunjiang 95A with wide compatibility,and further investigated the biological characteristics of the DA type Chunjiang 95A and its isonuclear alloplasmic CMS line Dian-I type Chunjiang 95A.The results show that DA type Chunjiang 95A is a japonicalinous CMS line and mainly typical abortive,which is better in fertility stability than stained abortive typeJaponica CMS lines.The DA type Chunjiang 95A is featured with high stigma exsertion,good flowering habit,high outcrossing rate and wide compatibility.Its recoverability differs from stained abortive typeJaponicaCMS lines.Moreover,we discussed genetic improvement of the typical abortive type JaponicaCMS lines and the application prospects of heterosis.展开更多
Taonong 1 A, developed from the cross of Jin 23A/（644B /Yixiang B） F2 and its successive backcrosses over years, is an indica CMS line in rice. It is characteristic of good agronomic characters, restorability, fine ...Taonong 1 A, developed from the cross of Jin 23A/（644B /Yixiang B） F2 and its successive backcrosses over years, is an indica CMS line in rice. It is characteristic of good agronomic characters, restorability, fine grain quality and high multiplication and hybrid seed yield. In 2012, its F1 hybrid combination Taoyou Xi- angzhan （Taonong 1A/Huanghuazhan） was evaluated as a 2nd class fine quality rice variety in Hunan Province. Both Taonong 1A and Taoyou Xiangzhan were regis- tered for release to commercial production by Hunan Provincial Crop Variety Ap- praisal Committee in 2015.展开更多
Breeding sterile lines is the key to the development of hybrid rice with wide adaptability. However, at present, few wide-adaptability sterile lines have been applied in production practice. In this study, Yungu 3A, a...Breeding sterile lines is the key to the development of hybrid rice with wide adaptability. However, at present, few wide-adaptability sterile lines have been applied in production practice. In this study, Yungu 3A, a new WA-type Indica CMS line with good grain quality, was developed by hybridization between Yunfeng 66A with wide adaptability as female parent and F1 plants of Yunfeng 66B/D62B as male parent and continuous backcrossing. According to the results, the finally obtained lndica CMS line Yungu 3A has good plant type and leaf shape, strong tillering ability, excellent flowering habit, stable and complete male sterility with the sterile plant rate and pollen sterility rate of 100%, strong combining ability, high outcrossing rate, low sensitivity to light and temperature, and strong disease resistance, which was approved by Yunnan Provincial Crop Variety Appraisal Committee in 2013. Yungu 3A is conducive to the development of new hybrid rice combinations with good quality and wide adaptability, exhibiting a promising prospect of application.展开更多
An in vitro shoot regeneration procedure was developed in pepper （ Capsicum annuum L. ） cytoplasmic male sterility （CMS） lines 9704A and 8214A using cotyledon as explant. The callus and bud cluster derived from co...An in vitro shoot regeneration procedure was developed in pepper （ Capsicum annuum L. ） cytoplasmic male sterility （CMS） lines 9704A and 8214A using cotyledon as explant. The callus and bud cluster derived from cotyledon tissue explants were proliferated on Murashige and Skoog （MS） medium supplemented with different combinations of 6-benzladenine （6-BA）, indole-3-acetic acid （IAA）, gibberellic acid （GA3） and silver nitrate （AgNO3）. From the formula of MS appended with 5.0 mg/L 6-BA, 1.0 mg/L IAA and 5.0 mg/L AgNO3, for the explants callus and bud cluster, the maximum differentiation rates （ respectively 100.0% and 58.3% ） and average number of adventitious bud from each explant （respectively 18.8 and 13.2） were obtained. The optimum medium combination for the elongation of adventitious bud was determined to be： MS ＋ 3.0 mg/L 6-BA ＋ 1.0 mg/L IAA ＋ 5.0 mg/L AgNO3 ＋ 2.0 mg/L GA3, from which the elongation rates of buds from callus and bud cluster were both 100%, and the average number of per explant adventitious bud number reached 6.3 and 5.8, respectively. And all the elongated shoots were successfully rooted on half-strength MS medium supplemented with 0.3-0.5 mg/L IAA.展开更多
Five cytoplasmic male sterile （CMS） lines were used as parents in an incomplete diallet cross and six restorer lines of rice design （Nc II design）. Thirty hybrid combinations with the same growth period were selec...Five cytoplasmic male sterile （CMS） lines were used as parents in an incomplete diallet cross and six restorer lines of rice design （Nc II design）. Thirty hybrid combinations with the same growth period were selected as experimental ma- terials to investigate the heterosis, combined ability and heredity of Cd content in brown rice of indica hybrid rice. According to the results, Cd content in brown rice showed a significantly negative heterosis; the general combining ability and specific combination ability of Cd content in CMS and restorer lines both reached extremely significant level （P〈0.01）, indicating that both genetic improvement of parents and e- valuation of combinations are important to the breeding of hybrid combinations with low accumulation of Cd; the broad-sense heritabitity and narrow-sense heritability of Cd content were both relatively high with slight differences, which respectively reached 97.73% and 80.10%, indicating that Cd content in brown rice mainly de- pends on the additive action of genes; in addition, parent improvement showed bet- ter effect on the selection of early generation.展开更多
There is a puzzling astrophysical result concerning the latest observation of the absorption profile of the redshifted radio line 21 cm from the early Universe(as described in Bowman et al.). The amplitude of the prof...There is a puzzling astrophysical result concerning the latest observation of the absorption profile of the redshifted radio line 21 cm from the early Universe(as described in Bowman et al.). The amplitude of the profile was more than a factor of two greater than the largest predictions. This could mean that the primordial hydrogen gas was much cooler than expected. Some explanations in the literature suggested a possible cooling of baryons either by unspecified dark matter particles or by some exotic dark matter particles with a charge a million times smaller than the electron charge. Other explanations required an additional radio background. In the present paper, we entertain a possible different explanation for the above puzzling observational result: the explanation is based on the alternative kind of hydrogen atoms(AKHA),whose existence was previously demonstrated theoretically, as well as by the analysis of atomic experiments. Namely, the AKHA are expected to decouple from the cosmic microwave background(CMB) much earlier(in the course of the Universe expansion) than usual hydrogen atoms, so that the AKHA temperature is significantly lower than that of usual hydrogen atoms. This seems to lower the excitation(spin) temperature of the hyperfine doublet(responsible for the 21 cm line) sufficiently enough for explaining the above puzzling observational result. This possible explanation appears to be more specific and natural than the previous possible explanations. Further observational studies of the redshifted 21 cm radio line from the early Universe could help to verify which explanation is the most relevant.展开更多
Xiangxiang 2A has an evident drawback, i.e., instability in male sterility under higher temperature conditions resulting from the existence of minor restoring genes in it, which greatly hampered the extension of its e...Xiangxiang 2A has an evident drawback, i.e., instability in male sterility under higher temperature conditions resulting from the existence of minor restoring genes in it, which greatly hampered the extension of its elite hybrid Xiangyou 63 with both high yield and fine quality in commercial production. To improve Xiangxiang 2A, the hybridization of Xiangxiang 2B with V20 B was made again in 1990. A new aromatic CMS line Xinxiang A was successfully developed in 1994. It not only retains the favorable characteristics of Xiangxiang 2A in grain quality and combining ability, but also expresses complete and stable male sterility and high seed production yield potential. Up to now, by using it as female parent, a series of quasi aromatic hybrids have been developed. Some of them have been released to farmers. Because such hybrids can not only yield higher or as high as but also possess a better grain quality than the current common high yielding hybrid rice varieties,so that they are preferred and well welcome by the farmers in China. The planting area under these hybrids is increasing rapidly in China.展开更多
基金Supported by the National High Technology Research and Development Program ofChina (863 Program) (2010AA101301)the Program of Breeding and Experimental Demonstration of Super Hybrid Rice in China from Ministry of Agriculture+1 种基金the 0406 Program of Zhejiang Provincethe Fundamental Research Fund of China National RiceResearch Institute (2009RG001-5)~~
文摘[Objective] To breed and utilize the japonicalinous cytoplasmic male sterile （CMS） line Chunjiang 19A with wide compatibility and high outcrossing rate. [Method] Cbunjiang 16A was used as the female parent to cross with Indica-Japonica crossing material B125, which was used as male parent. Backcross breeding was contin- ued for consecutive generations to breed the CMS lines with wide compatibility and high outcrossing rate. [Result] Chunjiang 19A is a late medium Japonica CMS line with good fertility stability. The proportion of sterile plants and pollen abortion rates are 100% and the Cheng＇s index is 14. It is the japonicalinous CMS line with early flowering, partial stigma exsertion, high outcrossing rate, wide compatibility, high re- sistance to stripe disease and good combining ability. The hybrid rice combinations originated from Chunjiang 19A have strong tUlering ability, dominant heterosis, high resistance to stripe disease, great yield potential and good color change at mature stage. [Conclusion] The successful breeding of Chunjiang 19A laid good foundation for the breeding of Japonica hybrid rice and Indica-Japonica hybrid rice combinations with high seed production and dominant heterosis, showing a promising application prospect.
基金Supported by National Rural Areas Project Application in the 12~(th) Five-Year Period(2012AA101201-2)Key Project of the National 12thFive-Year Research Program of China(2011BAD35B02-05)+6 种基金Key Program for International S&T Cooperation Projects of China(2012DF131220)Guangxi Scientific Research and Technological Development Projects(GKG1123001-4H,GKG1123001-4F)"Bagui Scholars"Special Funds of Guangxi Zhuang Autonomous RegionNatural Science Foundation of Guangxi Zhuang Autonomous Region(2010GXNSFA013085)Youth Science Foundation of Guangxi Zhuang Autonomous Region(GKQ0991054)Chairman Science and Technology Fund of Guangxi Zhuang Autonomous Region(11166-05)Fundamental Research Funds of Guangxi Academy of Agricultural Sciences(200920F)~~
文摘Longfeng A, derived from the cross of Bo A/（Zhenshan 97B/Bo B F1//Bo B/Gui 2 F1）, is a new high-quality indica CMS line with soft-grain characteristics in cooking rice. The CMS line is characterized by good agronomic traits, complete pol en sterility, stale fertility, favorable outcrossing habits, high combining ability and good grain quality. It was technical y identified by Guangxi Crop Variety Appraisal Committee in June, 2013.
文摘[Objective] Understanding the photosynthetic characteristics of the rice CMS line Renong 1A with leaf color markers can promote its utilization in breeding. [Method] The wild type （WT） of rice spontaneous mutant with virescent-yellow leaves that was the male parent of Renong 1A was selected as the control, and the contents of photosynthetic pigments, photosynthetic parameters, light-response curve and chlorophyll fluorescence kinetic parameters of Renong 1A were measured at the tillering stage. [Result] New leaves of Renong 1A yellowed obviously in the early period. Chlorophyll content, photosynthetic rate and values of parameters Pdt, F/Fm Fv＇/Fm＇,φPSII, and ETR of Renong 1A were all significantly lower than those of the control. However, there was no difference between Renong 1A and the control in terms of photosynthetic rate of leaves turning green. [Conclusion] The photosynthetic capacity of new leaves of Renong 1A decreased at the early stage due to the reduction of chlorophyll content, and then it became normal at the later stage with the increase of chlorophyll content.
基金Supported by Jiangsu Agricultural Science and Technology Independent Innovation Fund(CX[12]1003)Jiangsu Science and Technology Support Program(BE2013301)Earmarked Fund for China Agriculture Research System(CARS-01-47)~~
文摘Ningxian 2A is a new Indica CMS line with WA type sterile cytoplasm in rice. It was developed from the testcross between WA type indica CMS line Jin 23A and the single plant selected from the F_4 population of the cross Wuxiang 2B×Jin 23B followed by successive backcross over years. In September, 2014, it was technically identified by Jiangsu Provincial Crop Variety Appraisal Committee. Ningxian 2A has the characteristics of complete pollen sterility, high outcrossing rate, good plant type, high combining ability and good grain quality. Among its hybrids, Ningxian you 8（ Ningxian 2A×R08） was registered and released for commercial production in Jiangsu Province in May, 2015.
基金Supported by National Nonprofit Institute Research Grant of CATAS-TCGRI(1630032014031)Natural Science Foundation of Hainan Province(313071)+2 种基金Scientific Research Fund for Outstanding Overseas Chinese Scholars(2013)Hunan Provincial Science and Technology Project,China(2013NK3037)Research Foundation of Education Bureau of Hunan Province(13C392)~~
文摘Renong 1Ais a new indica CMS line with leaf color marker, developed by testcrossing and continuous backcrossing, using a spontaneous mutant with vires-cent-yel ow leaf isolated from the progenies of T98B /Jin 23B ×Yixiang 1B as the male parent, and Fengyuan A as the female parent. Al the chlorotic leaves of Renong 1A turn green in later developmental stages from leaf tip to base. This is the reason why Renong 1A is a new ideal leaf color marker material in indica rice. It shows apparent and stable leaf marker trait, good agronomic traits, high outcross-ing rate, complete pol en sterility, fine grain quality and high combining ability. Renong 1A has already been technical y identified and certified by Hainan Provincial Crop Variety Appraisal Committee in 2013.
基金Supported by the Science and Technology Innovation Program of Nantong City,Jiangsu Province(HL2012019)~~
文摘Yangfujing 7A, derived from the cross between Xu 9201A and Yangfujing 7 and its successive backcrosses, is a BT-type japonica CMS line developed by the Agricultural Institute of Riparian Region of Jiangsu Province. It shows good integrat- ed characteristics, stable male sterility, good flowering habits, high out crossing rate, strong disease resistance, fine grain quality （reaching the 1st class of national standards for fine quality rice） and high combining ability. In 2012, it was technically identified in Jiangsu Province. Its F1 hybrid combination Tongyoujingl （Yangfujing 7 A/R98）, showing high yield and good grain quality, was registered and released to commercial production by Jiangsu Crop Variety Appraisal Committee in 2013.
文摘Xinlong A was a high quality indica CMS line developed with early rice intermediate material 05Zao20(Zhouyou 903/Zhong9B F6)as female parent and IR58025B/Q96 F4 as male parent,Jin23A was then used as female parent for test crossing with BC,and backcrossed and bred with complete fertility and abortion lines.The male sterile line had the characteristics of good agronomic characters,strong combining ability,good resistance,high yield and good quality which reaches gradeⅡstandard of national high quality rice.It showed broad prospects and was technically identified in Jiangxi Province in 2017.
基金Supported by Key Research Project of Zhejiang Province(2008C22074)0406 Program of Zhejiang Province+2 种基金Fund for theConversion of Agricultural Science and Technology Achievement inZhejiang ProvinceBasic Operation Fund of China National Rice Re-search Institutethe Program of Breeding and Experimental Dem-onstration of Super Hybrid Rice in China from Ministry of Agriculture.
文摘From the view of methodology for genetic improvement ofJaponicacytoplasmic male sterile(CMS) lines,we introduced the breeding process of the dwarf-abortive type(DA type)JaponicaCMS line Chunjiang 95A with wide compatibility,and further investigated the biological characteristics of the DA type Chunjiang 95A and its isonuclear alloplasmic CMS line Dian-I type Chunjiang 95A.The results show that DA type Chunjiang 95A is a japonicalinous CMS line and mainly typical abortive,which is better in fertility stability than stained abortive typeJaponica CMS lines.The DA type Chunjiang 95A is featured with high stigma exsertion,good flowering habit,high outcrossing rate and wide compatibility.Its recoverability differs from stained abortive typeJaponicaCMS lines.Moreover,we discussed genetic improvement of the typical abortive type JaponicaCMS lines and the application prospects of heterosis.
基金Supported by New Rice Variety Breeding of High-grade and High-quality Rice Industry Improvement in Hunan Province~~
文摘Taonong 1 A, developed from the cross of Jin 23A/（644B /Yixiang B） F2 and its successive backcrosses over years, is an indica CMS line in rice. It is characteristic of good agronomic characters, restorability, fine grain quality and high multiplication and hybrid seed yield. In 2012, its F1 hybrid combination Taoyou Xi- angzhan （Taonong 1A/Huanghuazhan） was evaluated as a 2nd class fine quality rice variety in Hunan Province. Both Taonong 1A and Taoyou Xiangzhan were regis- tered for release to commercial production by Hunan Provincial Crop Variety Ap- praisal Committee in 2015.
基金Supported by Project for Introduction and Training of High-Level Technological Talents of Yunnan Province(2009CI126)New Product Program of Yunnan Province(2011BB002)Project for Construction of Science and Technology Innovation Platform of Yunnan Province(2013DH006)
文摘Breeding sterile lines is the key to the development of hybrid rice with wide adaptability. However, at present, few wide-adaptability sterile lines have been applied in production practice. In this study, Yungu 3A, a new WA-type Indica CMS line with good grain quality, was developed by hybridization between Yunfeng 66A with wide adaptability as female parent and F1 plants of Yunfeng 66B/D62B as male parent and continuous backcrossing. According to the results, the finally obtained lndica CMS line Yungu 3A has good plant type and leaf shape, strong tillering ability, excellent flowering habit, stable and complete male sterility with the sterile plant rate and pollen sterility rate of 100%, strong combining ability, high outcrossing rate, low sensitivity to light and temperature, and strong disease resistance, which was approved by Yunnan Provincial Crop Variety Appraisal Committee in 2013. Yungu 3A is conducive to the development of new hybrid rice combinations with good quality and wide adaptability, exhibiting a promising prospect of application.
基金Supported by "863" High Tech Project of China (2001AA241121-10) Natural Science Foundation of Yunnan Province (2005C0023Q)~~
文摘An in vitro shoot regeneration procedure was developed in pepper （ Capsicum annuum L. ） cytoplasmic male sterility （CMS） lines 9704A and 8214A using cotyledon as explant. The callus and bud cluster derived from cotyledon tissue explants were proliferated on Murashige and Skoog （MS） medium supplemented with different combinations of 6-benzladenine （6-BA）, indole-3-acetic acid （IAA）, gibberellic acid （GA3） and silver nitrate （AgNO3）. From the formula of MS appended with 5.0 mg/L 6-BA, 1.0 mg/L IAA and 5.0 mg/L AgNO3, for the explants callus and bud cluster, the maximum differentiation rates （ respectively 100.0% and 58.3% ） and average number of adventitious bud from each explant （respectively 18.8 and 13.2） were obtained. The optimum medium combination for the elongation of adventitious bud was determined to be： MS ＋ 3.0 mg/L 6-BA ＋ 1.0 mg/L IAA ＋ 5.0 mg/L AgNO3 ＋ 2.0 mg/L GA3, from which the elongation rates of buds from callus and bud cluster were both 100%, and the average number of per explant adventitious bud number reached 6.3 and 5.8, respectively. And all the elongated shoots were successfully rooted on half-strength MS medium supplemented with 0.3-0.5 mg/L IAA.
基金Supported by Youth Fund Project of Sichuan Academy of Agricultural Sciences(2009QNJJ015)~~
文摘Five cytoplasmic male sterile （CMS） lines were used as parents in an incomplete diallet cross and six restorer lines of rice design （Nc II design）. Thirty hybrid combinations with the same growth period were selected as experimental ma- terials to investigate the heterosis, combined ability and heredity of Cd content in brown rice of indica hybrid rice. According to the results, Cd content in brown rice showed a significantly negative heterosis; the general combining ability and specific combination ability of Cd content in CMS and restorer lines both reached extremely significant level （P〈0.01）, indicating that both genetic improvement of parents and e- valuation of combinations are important to the breeding of hybrid combinations with low accumulation of Cd; the broad-sense heritabitity and narrow-sense heritability of Cd content were both relatively high with slight differences, which respectively reached 97.73% and 80.10%, indicating that Cd content in brown rice mainly de- pends on the additive action of genes; in addition, parent improvement showed bet- ter effect on the selection of early generation.
文摘There is a puzzling astrophysical result concerning the latest observation of the absorption profile of the redshifted radio line 21 cm from the early Universe(as described in Bowman et al.). The amplitude of the profile was more than a factor of two greater than the largest predictions. This could mean that the primordial hydrogen gas was much cooler than expected. Some explanations in the literature suggested a possible cooling of baryons either by unspecified dark matter particles or by some exotic dark matter particles with a charge a million times smaller than the electron charge. Other explanations required an additional radio background. In the present paper, we entertain a possible different explanation for the above puzzling observational result: the explanation is based on the alternative kind of hydrogen atoms(AKHA),whose existence was previously demonstrated theoretically, as well as by the analysis of atomic experiments. Namely, the AKHA are expected to decouple from the cosmic microwave background(CMB) much earlier(in the course of the Universe expansion) than usual hydrogen atoms, so that the AKHA temperature is significantly lower than that of usual hydrogen atoms. This seems to lower the excitation(spin) temperature of the hyperfine doublet(responsible for the 21 cm line) sufficiently enough for explaining the above puzzling observational result. This possible explanation appears to be more specific and natural than the previous possible explanations. Further observational studies of the redshifted 21 cm radio line from the early Universe could help to verify which explanation is the most relevant.
文摘Xiangxiang 2A has an evident drawback, i.e., instability in male sterility under higher temperature conditions resulting from the existence of minor restoring genes in it, which greatly hampered the extension of its elite hybrid Xiangyou 63 with both high yield and fine quality in commercial production. To improve Xiangxiang 2A, the hybridization of Xiangxiang 2B with V20 B was made again in 1990. A new aromatic CMS line Xinxiang A was successfully developed in 1994. It not only retains the favorable characteristics of Xiangxiang 2A in grain quality and combining ability, but also expresses complete and stable male sterility and high seed production yield potential. Up to now, by using it as female parent, a series of quasi aromatic hybrids have been developed. Some of them have been released to farmers. Because such hybrids can not only yield higher or as high as but also possess a better grain quality than the current common high yielding hybrid rice varieties,so that they are preferred and well welcome by the farmers in China. The planting area under these hybrids is increasing rapidly in China.
