The seed production of male and female parent of ‘Hunzhi 1＇ contained bentazon susceptible gene was studied. The result showed that spraying 3. 375 L/hm2 48% bentazon aqua could control the self-pollinated fertiliza...The seed production of male and female parent of ‘Hunzhi 1＇ contained bentazon susceptible gene was studied. The result showed that spraying 3. 375 L/hm2 48% bentazon aqua could control the self-pollinated fertilization rate below 1.0% and survival plant rate was 0. The spray of bentazon would not influence MC526 pollen vitality. Seed setting rate of female parent was not obvious different from that of control group with spraying bentazon aqua more than 3. 375 L/hm^2 from the sprouting appearing period to full heading stage. This demonstrated that bentazon aqua had no influence on seed setting rate during florescence of female parent. The weight ratio between male parent seeds and female parent seeds was 1 to 5, then seeds from parents with that weight ratio would be mixedly planted for seed production. With this weight ratio, relative proper structure of panicle and grain would be obtained ,panicle ratio was 1 to 4.3, glumous flowers ratio was 1 to 3.5. Cross seed-setting rate of female parent was 72.6% and seed production per hm^2 was 66 000 kg.展开更多
In the research, 20 indica hybrid rice varieties were investigated under high-dense and low-amount, mid-dense and mid-amount and low-dense and high-amount fertilization conditions in order to explore correlation betwe...In the research, 20 indica hybrid rice varieties were investigated under high-dense and low-amount, mid-dense and mid-amount and low-dense and high-amount fertilization conditions in order to explore correlation between LAI in ful heading stage with yield and to analyze yield differences, yield components, material accumulation and transferring, as wel as correlation between key cultivation factors and yield. Final y, approaches and key technology for yield breakthrough were dis-cussed, which provides theoretical and technological references for rice high yield.展开更多
[Objectives]Current hybrid rice seed production mechanization and a new kind of hybrid rice seed production mechanization using Bentazone sensitive lethal genes for mechanized seed production technology are introduced...[Objectives]Current hybrid rice seed production mechanization and a new kind of hybrid rice seed production mechanization using Bentazone sensitive lethal genes for mechanized seed production technology are introduced in this paper.[Method]Sensitive Restorer Bentazone lethal dose of filtering,parental and seed weight are bred combinations of several aspects of the system described,and presented mechanized seed technology new research directions.[Results]The method of using Bentazone sensitive lethal genes for mechanized seed production technology is feasible,economic,seed production and combination advantages.[Conclusions] Using Bentazone sensitive lethal genes for mechanized seed production technology is the new study direction of mechanic production.展开更多
Yanliangyou 2208, bred by the Jiangsu Institute of Agricultural Sciences in Coastal Areas, is a two-line indica hybrid rice combination characterized with strong heterosis, moderate maturity, wide adaptability, good s...Yanliangyou 2208, bred by the Jiangsu Institute of Agricultural Sciences in Coastal Areas, is a two-line indica hybrid rice combination characterized with strong heterosis, moderate maturity, wide adaptability, good stability and disease resistance. It was identified as a new variety by the National Crop Variety Approval Committee in 2013. According to the characteristics of parents of Yanliangyou 2208 and com- bined with many years of seed production experience, high-yielding seed production techniques of Yanliangyou 2208 are summed up in this paper.展开更多
According to seed production of Yanliangyou 888, a two-line hybrid rice variety, the research reviewed seed production characters, as follows： to improve outcrossing rate and spike size provided sufficient spikes of ...According to seed production of Yanliangyou 888, a two-line hybrid rice variety, the research reviewed seed production characters, as follows： to improve outcrossing rate and spike size provided sufficient spikes of female/male parents. The seed production techniques include scientific arrangement of seeding interval, cultivating strong multi-tiller seedlings, scientific arrangement of row ratio of inter- cropping with adequate basic seedlings, scientific water and fertilizer management, improving outcrossing rate by synthesis measures, disease/insect control, and rein- forcing production management.展开更多
Four pairs of microsatellite molecular polymorphism primers were used to analyse microsatellite fingerprints of 188 seedlings derived from an open-pollinated progeny grafted Eucalyptus globulus breeding arboretum in V...Four pairs of microsatellite molecular polymorphism primers were used to analyse microsatellite fingerprints of 188 seedlings derived from an open-pollinated progeny grafted Eucalyptus globulus breeding arboretum in Victoria, south-eastern Australia. The microsatellite loci chosen for this study were highly polymorphic with the mean number of alleles per locus of 14.25. Individual mothers varied in their outcrosssing rate estimate from 15% to 95%, the overall outcrossing level in the arboretum was 47.9% and the contamination rate was 17.6%. The high selfing level was likely to result in marked inbreeding depression in the performance of open-pollinated seed lots. Open-pollinated seeds collected from such arboreta are not advisable because of its low genetic quality, although such arboreta may be useful for the seed production through large-scale manual pollination or collecting seeds only from trees or genotypes within the arboretum that have high outcrossing rates.展开更多
Rong 18A, bred by Crop Research Institute, Chengdu Academy of Agri- culture and Forestry Sciences is a new blast-highly resistant and high-combining ability hybrid rice sterile line. It is currently one of the male st...Rong 18A, bred by Crop Research Institute, Chengdu Academy of Agri- culture and Forestry Sciences is a new blast-highly resistant and high-combining ability hybrid rice sterile line. It is currently one of the male sterile lines in Sichuan Province which combine well high grain quality and rice blast resistance. More than 20 combinations of Rong 18A have passed the national and provincial variety iden- tification. Combined with the climate conditions in Chengdu, the key points of high- yielding seed production techniques for Rong18A are analyzed and summarized in this paper.展开更多
AIM： To investigate the transactivating effect of pre-S2 protein of hepatitis B virus （HBV） and construct a subtractive cDNA library of genes transactivated by pre-S2 protein with suppression subtractive hybridizat...AIM： To investigate the transactivating effect of pre-S2 protein of hepatitis B virus （HBV） and construct a subtractive cDNA library of genes transactivated by pre-S2 protein with suppression subtractive hybridization （SSH） technique, and to pave the way for elucidating the pathogenesis of HBV infection. METHODS： pcDNA3.1（-）-pre-S2 containing pre-S2 region of HBV genome was constructed by routine molecular methods. HepG2 cells were cotransfected with pcDNA3.1 （-）-pre-S21pSV-lacZ and empty pcDNA3.1（-）/pSV-lacZ. After 48 h, cells were collected and detected for the expression of β-galactosidase （β-gal）. SSH and bioinformatics techniques were used, the mRNA of HepG2 cells transfected with pcDNA3.1（-）-pre-S2 and pcDNA3.1（-） empty vector was isolated, respectively, cDNA was synthesized. After digestion with restriction enzyme RsaI, cDNA fragments were obtained. Tester cDNA was then divided into two groups and ligated to the specific adaptor 1 and adaptor 2, respectively. After tester cDNA was hybridized with driver cDNA twice and underwent two times of nested PCR, amplified cDNA fragments were subcloned into pGEM-Teasy vectors to set up the subtractive library. Amplification of the library was carried out with E.coli strain DH5α The cDNA was sequenced and analyzed in GenBank with Blast search after PCR. RESULTS： The pre-S2 mRNA could be detected in HepG2 cells transfected with pcDNA3.1（-）-pre-S2 plasmid. The activity of β-gal in HepG2 cells transfected with pcDNA3.1 （-）-pre-S2/pSV-lacZ was 7.0 times higher than that of control plasmid （P〈0.01）. The subtractive library of genes transactivated by HBV pre-S2 protein was constructed successfully. The amplified library contains 96 positiveclones. Colony PCR showed that 86 clones contained 200-1 000 bp inserts. Sequence analysis was performed in 50 clones randomly, and the full length sequences were obtained with bioinformatics method and searched for homologous DNA sequence from GenBank, altogether 25 coding sequences were obtained, these cDNA sequences might be the target genes transactivated by pre-S2 protein. CONCLUSION： The pre-S2 protein of HBV has transactivating effect on SV40 early promoter. The obtained sequences may be target genes transactivated by pre-S2 protein among which some genes coding proteins involved in cell cycle regulation, metabolism, immunity, signal transcluction and cell apoptosis.This finding brings some new clues for studying the biological functions of pre-S2 protein and further understanding of HBV hepatocarcinogesis.展开更多
The cultivation of the first filial generation of monoploid gametophyte clones of different Laminaria species (hybrid Laminaria) is an effective way of utilizing heterozygous vigor (heterosis). A female gametophyte cl...The cultivation of the first filial generation of monoploid gametophyte clones of different Laminaria species (hybrid Laminaria) is an effective way of utilizing heterozygous vigor (heterosis). A female gametophyte clone of L. japonica and a male gametophyte clone of L. longissima were hybridized, generating Dongfang No.2 hybrid Laminaria. The parentage of this hybrid Laminaria was determined using AFLP of total DNA, SNP of the ITS region of ribosomal RNA transcription unit and microsatellite DNA variation at two loci. In addition to 167 AFLP bands shared by Dongfang No.2, L. japonica and L. longissima, Dongfang No.2 hybrid Laminaria shared another 70 and 55 bands with L. japonica and L. longissima, respectively, which were obviously more than 11 bands shared by L. japonica and L. longissima. Dongfang No.2 held both ‘T’ and ‘C’ at position 847 of the ITS region, while ‘T’ at this position was specific for L. japonica and ‘C’ for L. longissima, respectively. Dongfang No.2 also held the microsatellite DNA alleles of two parents together at two microsatellite DNA marker loci. These observations clearly proved that Dongfang No.2 is a true hybrid of L. japonica and L. longissiuma. Unfortunately, the origin of the chloroplast of Dongfang No.2 was not determined based on the variation of RuBisCo spacer. More sequence variants of both ITS region and RuBisCo spacer were identified in Dongfang No.2 and most of them did not exist in either L. japonica or L. longissima. The unexpected variants may be due to the mutation of ga- metophyte clones occurring during their vegetative amplification.展开更多
The genetic basis of heterosis was studied through mid-parent, standard variety and better parent for 11 quantitative traits in 17 parental lines and their 10 selected hybrids in rice (Oryza sativa L.).The characters ...The genetic basis of heterosis was studied through mid-parent, standard variety and better parent for 11 quantitative traits in 17 parental lines and their 10 selected hybrids in rice (Oryza sativa L.).The characters were plant height,days to flag leaf initiation, days to first panicle initiation, days to 100% flowering, panicle length,flag leaf length, days to maturity, number of fertile spikelet/panicle, number of effective tillers/hill, grain yield/10-hill, and 1000-grain weight.In general the hybrids performed significantly better than the respective parents.Significant heterosis was observed for most of the studied characters. Among the 10 hybrids, four hybrids viz., 17A×45R,25A×37R,27A×39R,31A×47R,and 35A×47R showed highest heterosis in 10-hill grain yield/10-hill. Inbreeding depression of F2 progeny was also studied for 11 characters of 10 hybrids.Both positive and negative inbreeding depression were found in many crosses for the studied characters,but none was found significant. Selection of good parents was found to be the most important for developing high yielding hybrid rice varieties.展开更多
[Objective] This study aimed to explore germplasm resources of salt toler- ant Spartina alterniflora and high yield rice, and develop an innovative strategy for distant hybridization between S. altemiflora and rice. [...[Objective] This study aimed to explore germplasm resources of salt toler- ant Spartina alterniflora and high yield rice, and develop an innovative strategy for distant hybridization between S. altemiflora and rice. [Method] Crossing （rice ♀ ）： hot water emasculation and glume-cutting pollination method, heat emasculation and pollen-suction pollination method; reciprocal crossing （S. alterniflora ♀ glume-cutting emasculation and pollination method, continuous emasculation-pollination method, hot water emasculation and continuous emasculation-pollination method. [Result] In crossing groups （rice ♀ × S. alterniflora ♂ ）, compared with hot water emasculation and glume-cutting pollination treatment, the number of seed-bearing combinations, seed number per spike and seedling emergence rate in heat emasculation and pollen-suction pollination treatment were improved by 34.09%, 121.21% and 60.07%, respectively; hybridization efficiency was improved by 6-7 times. In reciprocal cross- ing groups （S. altemiflora ♀× rice ♂ ）, compared with glume-cutting emasculation and pollination treatment, the number of seed-bearing combinations and seed num- ber per spike in continuous emasculation-pollination treatment were improved by 3.14 and 4.21 times, respectively; seedling emergence rate was improved by 68.47%; hybridization efficiency was improved by 7-8 times. [Conclusion] Heat emas- culation and pollen-suction pollination method is suitable for hybridization between rice ♀× S. alterniflora ♂; continuous emasculation-pollination method is suitable for hybridization between S. alterniflora ♀× rice ♂.展开更多
Low soil nitrogen （N） and weed infestations are some of the major constraints to maize production in Nigeria. A split-split plot experiment in a randomized complete block design with three replicates was established...Low soil nitrogen （N） and weed infestations are some of the major constraints to maize production in Nigeria. A split-split plot experiment in a randomized complete block design with three replicates was established at two sites with different agroecological zones, Ikenne （Typic Paleudalf） and Shika （Typic Tropaquept）, in Nigeria in 2002 and 2003 rainy seasons to investigate the responses of four maize genotypes （Oba super II, Low N pool C2, TZB-SR, and ACR 8328 BN C7） to N fertilizer applied at four rates, 0, 30, 60, and 90 kg N ha^-1, and three weed pressure treatments, no weed pressure （weekly weeding）, low weed pressure （inter-row weekly weeding）, and high weed pressure （no weeding throughout the growing season）. Growth and yield parameters of maize and weeds were taken at flowering and harvest. The results indicated that there was a significant reduction in maize leaf area, leaf area index, and photosynthetically active radiation due to weed interference at both sites. The application of nitrogen at 90 kg N ha^-1 significantly increased maize leaf area. Reductions in maize growth and yield at flowering and harvest were significant due to weed interference at both Ikenne and Shika, thus showing that the reductions in maize growth and yield due to weed interference were not ecological zone specific even though weed species and their seed banks may differ. Ameliorative management options could thus be the same in the two agroecological zones. Application of 90 kg N ha^-1 led to a significant increase in maize grain yield at Shika while there was no fertilizer effect at Ikenne on grain yield. There was no significant difference between 60 and 90 kg N ha^-1, suggesting that 60 kg N ha^-1 could be a possible replacement for the higher fertilizer rate at least for the identified maize genotypes. Low weed pressure treatment led to 26% and 35% reductions in maize grain yield at Ikenne and Shika, respectively, while 22% and 51% reductions, respectively, were observed due to high weed pressure. Generally, maize grain yield was higher at Ikenne than Shika. The maize genotypes Low N pool C2 and ACR 8328 PIN C7 performed better than the other genotypes at Ikenne while the maize genotype Oba super II had the best performance at harvest at Shika. Application of nitrogen increased weed biomass at flowering at Ikenne. The maize grain yield was highest in the N-efficient genotypes, Oba super II and Low N pool C2; the susceptible genotype TZB-SR had the least yield at Shika. There existed a negative and significant correlation between maize grain yield and weed biomass at both sites.展开更多
According to seed production practice, the seed production techniques for BenIiangyou 3113, a new two-Iine hybrid rice combination, were summarized. In or-der to obtaln high and stabIe yielding, the seed production of...According to seed production practice, the seed production techniques for BenIiangyou 3113, a new two-Iine hybrid rice combination, were summarized. In or-der to obtaln high and stabIe yielding, the seed production of BenIiangyou 3113 re-quires appropriate site seIection, rational sowing period, rational ratio between parental Iines, enhanced water and fertiIizer management, appropriate Ieaf cutting, strict weeding, good artificial poI ination and good pests and diseases controI.展开更多
Hybrid rice technology in China was developed in three stages. From the 1950s onwards, hybrid rice researchers, as typified by Yuan Longping, sought out a feasible approach to utilizing rice heterosis, and developed t...Hybrid rice technology in China was developed in three stages. From the 1950s onwards, hybrid rice researchers, as typified by Yuan Longping, sought out a feasible approach to utilizing rice heterosis, and developed the three-line indica hybrid rice. Led by the government, the hybrid rice technology R&D teams adopted the research mode of "large-scale cooperation"(大协作), and accomplished technical innovations in the three-line system, selective breeding, and production of hybrid seeds. In the ensuing decade, Yuan Longping and others discovered the photo-thermo sensitive genic male sterility(PTGMS) of rice and developed PTGMS lines, turning highly advantageous two-line rice breeding from scientific vision into reality. Over the next twenty-five years, China’s super-rice breeding program integrated the conventional, three-line, and two-line breeding methods with modern molecular biotechnology methods. For nearly half a century, China made outstanding attainments in acquiring quality strains that yielded enormous economic and social benefits. Throughout this process, factors such as urgent social demand for increased grain production and scientific research cooperation provided significant impetus.展开更多
Chuanxiang No.2058 is a new combination of three-line late indica hybrid rice bred based on sterile line Chuanxiang 29A and restorer Qiannanhui No.2058. In order to promote its application, seed production techniques ...Chuanxiang No.2058 is a new combination of three-line late indica hybrid rice bred based on sterile line Chuanxiang 29A and restorer Qiannanhui No.2058. In order to promote its application, seed production techniques of Chuanxiang No.2058 were explored during 2009-2010. The research detailed the seed production tech- niques from selection of seed production bases, rational arrangement of sowing gap stage, seedling cultivation in different stages, scientific arrangement of male/female parents, management of fertilizer and water, adjustment of florescence, artificial pol- lination, comprehensive treatment of disease and pest damages, and timely control- ling of abnormal and poorly-qualified rice.展开更多
High-quality hybrid rape Changzayou 3 is a new yellow-seed double-low rape variety with high yield, good resistance to diseases and lodging and high oil content, suitable for winter cropping in central China. Its high...High-quality hybrid rape Changzayou 3 is a new yellow-seed double-low rape variety with high yield, good resistance to diseases and lodging and high oil content, suitable for winter cropping in central China. Its high-yield cultivation tech- niques are mainly early seeding at proper time, thinning timely, rational close planting, scientific fertilization, control of diseases and pest and weeding.展开更多
Augmented randomized complete block test was conducted to evaluate the heterosis of 80 hybrid combinations from TGMS line 402S and its original parent Xiangyou 91S,and the combining a-bility of 40 testcrossing lines.T...Augmented randomized complete block test was conducted to evaluate the heterosis of 80 hybrid combinations from TGMS line 402S and its original parent Xiangyou 91S,and the combining a-bility of 40 testcrossing lines.The results of identification test showed that among 47 combinations yielding over the control Xiangyou 15,17 ones with 402S and 3 ones with Xiangyou 91S overyielded more than 20%,reaching the significant level of 1 %;and among 51 combinations yielding over their corresponding higher yield parents,18 ones with 402S and 9 ones with Xiangyou 91S overyielded at 5% or 1% significant level.The test for the GCA effect of all parents indicated that 402S possessed a stronger combining ability than Xiangyou 91S on yield,ailiquae of main inflorescence,total siliquae per plant,seed yield of single plant and 1000 seed weight.10 testcrossing lines with high GCA were picked out for next testcrosses.Among 8 agronomic traits,total siliquae per plant and seed yield of single plant were regarded as the key selecting indexes according to the correlation analysis between yield and the agronomic traits on heterosis and on the GCA effect of all parents.展开更多
This paper deals with the recent hybrid rice development in the Philippines and some information about developing economic and technical cooperation in hybrid rice between China and the Philippines.
基金Supported by the Important Science and Technology Key Project of An-hui Eleventh-five Year Plan(06003010B)the International Cooperation Program of Anhui Province(06088013)~~
文摘The seed production of male and female parent of ‘Hunzhi 1＇ contained bentazon susceptible gene was studied. The result showed that spraying 3. 375 L/hm2 48% bentazon aqua could control the self-pollinated fertilization rate below 1.0% and survival plant rate was 0. The spray of bentazon would not influence MC526 pollen vitality. Seed setting rate of female parent was not obvious different from that of control group with spraying bentazon aqua more than 3. 375 L/hm^2 from the sprouting appearing period to full heading stage. This demonstrated that bentazon aqua had no influence on seed setting rate during florescence of female parent. The weight ratio between male parent seeds and female parent seeds was 1 to 5, then seeds from parents with that weight ratio would be mixedly planted for seed production. With this weight ratio, relative proper structure of panicle and grain would be obtained ,panicle ratio was 1 to 4.3, glumous flowers ratio was 1 to 3.5. Cross seed-setting rate of female parent was 72.6% and seed production per hm^2 was 66 000 kg.
基金Supported by Rice Industry Technology System(2010030162011BAD16B05-1)~~
文摘In the research, 20 indica hybrid rice varieties were investigated under high-dense and low-amount, mid-dense and mid-amount and low-dense and high-amount fertilization conditions in order to explore correlation between LAI in ful heading stage with yield and to analyze yield differences, yield components, material accumulation and transferring, as wel as correlation between key cultivation factors and yield. Final y, approaches and key technology for yield breakthrough were dis-cussed, which provides theoretical and technological references for rice high yield.
文摘[Objectives]Current hybrid rice seed production mechanization and a new kind of hybrid rice seed production mechanization using Bentazone sensitive lethal genes for mechanized seed production technology are introduced in this paper.[Method]Sensitive Restorer Bentazone lethal dose of filtering,parental and seed weight are bred combinations of several aspects of the system described,and presented mechanized seed technology new research directions.[Results]The method of using Bentazone sensitive lethal genes for mechanized seed production technology is feasible,economic,seed production and combination advantages.[Conclusions] Using Bentazone sensitive lethal genes for mechanized seed production technology is the new study direction of mechanic production.
文摘Yanliangyou 2208, bred by the Jiangsu Institute of Agricultural Sciences in Coastal Areas, is a two-line indica hybrid rice combination characterized with strong heterosis, moderate maturity, wide adaptability, good stability and disease resistance. It was identified as a new variety by the National Crop Variety Approval Committee in 2013. According to the characteristics of parents of Yanliangyou 2208 and com- bined with many years of seed production experience, high-yielding seed production techniques of Yanliangyou 2208 are summed up in this paper.
基金Supported by National Key Technology R&D Program(BAD01B01,2015BAD01B02,2015BAD01B03)Independent Innovation Fund Project of Agricultural Science and Technology in Jiangsu Province(CX(15)1005-3-1)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA08030104-3)~~
文摘According to seed production of Yanliangyou 888, a two-line hybrid rice variety, the research reviewed seed production characters, as follows： to improve outcrossing rate and spike size provided sufficient spikes of female/male parents. The seed production techniques include scientific arrangement of seeding interval, cultivating strong multi-tiller seedlings, scientific arrangement of row ratio of inter- cropping with adequate basic seedlings, scientific water and fertilizer management, improving outcrossing rate by synthesis measures, disease/insect control, and rein- forcing production management.
基金This study was supported by State Administration of Foreign Experts Affairs, P. R. China (No.2001430007)
文摘Four pairs of microsatellite molecular polymorphism primers were used to analyse microsatellite fingerprints of 188 seedlings derived from an open-pollinated progeny grafted Eucalyptus globulus breeding arboretum in Victoria, south-eastern Australia. The microsatellite loci chosen for this study were highly polymorphic with the mean number of alleles per locus of 14.25. Individual mothers varied in their outcrosssing rate estimate from 15% to 95%, the overall outcrossing level in the arboretum was 47.9% and the contamination rate was 17.6%. The high selfing level was likely to result in marked inbreeding depression in the performance of open-pollinated seed lots. Open-pollinated seeds collected from such arboreta are not advisable because of its low genetic quality, although such arboreta may be useful for the seed production through large-scale manual pollination or collecting seeds only from trees or genotypes within the arboretum that have high outcrossing rates.
文摘Rong 18A, bred by Crop Research Institute, Chengdu Academy of Agri- culture and Forestry Sciences is a new blast-highly resistant and high-combining ability hybrid rice sterile line. It is currently one of the male sterile lines in Sichuan Province which combine well high grain quality and rice blast resistance. More than 20 combinations of Rong 18A have passed the national and provincial variety iden- tification. Combined with the climate conditions in Chengdu, the key points of high- yielding seed production techniques for Rong18A are analyzed and summarized in this paper.
文摘AIM： To investigate the transactivating effect of pre-S2 protein of hepatitis B virus （HBV） and construct a subtractive cDNA library of genes transactivated by pre-S2 protein with suppression subtractive hybridization （SSH） technique, and to pave the way for elucidating the pathogenesis of HBV infection. METHODS： pcDNA3.1（-）-pre-S2 containing pre-S2 region of HBV genome was constructed by routine molecular methods. HepG2 cells were cotransfected with pcDNA3.1 （-）-pre-S21pSV-lacZ and empty pcDNA3.1（-）/pSV-lacZ. After 48 h, cells were collected and detected for the expression of β-galactosidase （β-gal）. SSH and bioinformatics techniques were used, the mRNA of HepG2 cells transfected with pcDNA3.1（-）-pre-S2 and pcDNA3.1（-） empty vector was isolated, respectively, cDNA was synthesized. After digestion with restriction enzyme RsaI, cDNA fragments were obtained. Tester cDNA was then divided into two groups and ligated to the specific adaptor 1 and adaptor 2, respectively. After tester cDNA was hybridized with driver cDNA twice and underwent two times of nested PCR, amplified cDNA fragments were subcloned into pGEM-Teasy vectors to set up the subtractive library. Amplification of the library was carried out with E.coli strain DH5α The cDNA was sequenced and analyzed in GenBank with Blast search after PCR. RESULTS： The pre-S2 mRNA could be detected in HepG2 cells transfected with pcDNA3.1（-）-pre-S2 plasmid. The activity of β-gal in HepG2 cells transfected with pcDNA3.1 （-）-pre-S2/pSV-lacZ was 7.0 times higher than that of control plasmid （P〈0.01）. The subtractive library of genes transactivated by HBV pre-S2 protein was constructed successfully. The amplified library contains 96 positiveclones. Colony PCR showed that 86 clones contained 200-1 000 bp inserts. Sequence analysis was performed in 50 clones randomly, and the full length sequences were obtained with bioinformatics method and searched for homologous DNA sequence from GenBank, altogether 25 coding sequences were obtained, these cDNA sequences might be the target genes transactivated by pre-S2 protein. CONCLUSION： The pre-S2 protein of HBV has transactivating effect on SV40 early promoter. The obtained sequences may be target genes transactivated by pre-S2 protein among which some genes coding proteins involved in cell cycle regulation, metabolism, immunity, signal transcluction and cell apoptosis.This finding brings some new clues for studying the biological functions of pre-S2 protein and further understanding of HBV hepatocarcinogesis.
文摘The cultivation of the first filial generation of monoploid gametophyte clones of different Laminaria species (hybrid Laminaria) is an effective way of utilizing heterozygous vigor (heterosis). A female gametophyte clone of L. japonica and a male gametophyte clone of L. longissima were hybridized, generating Dongfang No.2 hybrid Laminaria. The parentage of this hybrid Laminaria was determined using AFLP of total DNA, SNP of the ITS region of ribosomal RNA transcription unit and microsatellite DNA variation at two loci. In addition to 167 AFLP bands shared by Dongfang No.2, L. japonica and L. longissima, Dongfang No.2 hybrid Laminaria shared another 70 and 55 bands with L. japonica and L. longissima, respectively, which were obviously more than 11 bands shared by L. japonica and L. longissima. Dongfang No.2 held both ‘T’ and ‘C’ at position 847 of the ITS region, while ‘T’ at this position was specific for L. japonica and ‘C’ for L. longissima, respectively. Dongfang No.2 also held the microsatellite DNA alleles of two parents together at two microsatellite DNA marker loci. These observations clearly proved that Dongfang No.2 is a true hybrid of L. japonica and L. longissiuma. Unfortunately, the origin of the chloroplast of Dongfang No.2 was not determined based on the variation of RuBisCo spacer. More sequence variants of both ITS region and RuBisCo spacer were identified in Dongfang No.2 and most of them did not exist in either L. japonica or L. longissima. The unexpected variants may be due to the mutation of ga- metophyte clones occurring during their vegetative amplification.
文摘The genetic basis of heterosis was studied through mid-parent, standard variety and better parent for 11 quantitative traits in 17 parental lines and their 10 selected hybrids in rice (Oryza sativa L.).The characters were plant height,days to flag leaf initiation, days to first panicle initiation, days to 100% flowering, panicle length,flag leaf length, days to maturity, number of fertile spikelet/panicle, number of effective tillers/hill, grain yield/10-hill, and 1000-grain weight.In general the hybrids performed significantly better than the respective parents.Significant heterosis was observed for most of the studied characters. Among the 10 hybrids, four hybrids viz., 17A×45R,25A×37R,27A×39R,31A×47R,and 35A×47R showed highest heterosis in 10-hill grain yield/10-hill. Inbreeding depression of F2 progeny was also studied for 11 characters of 10 hybrids.Both positive and negative inbreeding depression were found in many crosses for the studied characters,but none was found significant. Selection of good parents was found to be the most important for developing high yielding hybrid rice varieties.
基金Supported by 2014 Project for Scientific and Technological Innovation and Industrialization of Nantong City,Jiangsu Province"Breeding of New Varieties(Lines)of Saline-alkali Tolerant Spartina alterniflora and Rice in Coastal Areas"(HL2014020)2014 Program for Leading Talents of Scientific and Technological Innovation of Nanjing City,Jiangsu Province(616035)~~
文摘[Objective] This study aimed to explore germplasm resources of salt toler- ant Spartina alterniflora and high yield rice, and develop an innovative strategy for distant hybridization between S. altemiflora and rice. [Method] Crossing （rice ♀ ）： hot water emasculation and glume-cutting pollination method, heat emasculation and pollen-suction pollination method; reciprocal crossing （S. alterniflora ♀ glume-cutting emasculation and pollination method, continuous emasculation-pollination method, hot water emasculation and continuous emasculation-pollination method. [Result] In crossing groups （rice ♀ × S. alterniflora ♂ ）, compared with hot water emasculation and glume-cutting pollination treatment, the number of seed-bearing combinations, seed number per spike and seedling emergence rate in heat emasculation and pollen-suction pollination treatment were improved by 34.09%, 121.21% and 60.07%, respectively; hybridization efficiency was improved by 6-7 times. In reciprocal cross- ing groups （S. altemiflora ♀× rice ♂ ）, compared with glume-cutting emasculation and pollination treatment, the number of seed-bearing combinations and seed num- ber per spike in continuous emasculation-pollination treatment were improved by 3.14 and 4.21 times, respectively; seedling emergence rate was improved by 68.47%; hybridization efficiency was improved by 7-8 times. [Conclusion] Heat emas- culation and pollen-suction pollination method is suitable for hybridization between rice ♀× S. alterniflora ♂; continuous emasculation-pollination method is suitable for hybridization between S. alterniflora ♀× rice ♂.
基金supported by the International Institute of Tropical Agriculture (IITA),Ibadan,Nigeria
文摘Low soil nitrogen （N） and weed infestations are some of the major constraints to maize production in Nigeria. A split-split plot experiment in a randomized complete block design with three replicates was established at two sites with different agroecological zones, Ikenne （Typic Paleudalf） and Shika （Typic Tropaquept）, in Nigeria in 2002 and 2003 rainy seasons to investigate the responses of four maize genotypes （Oba super II, Low N pool C2, TZB-SR, and ACR 8328 BN C7） to N fertilizer applied at four rates, 0, 30, 60, and 90 kg N ha^-1, and three weed pressure treatments, no weed pressure （weekly weeding）, low weed pressure （inter-row weekly weeding）, and high weed pressure （no weeding throughout the growing season）. Growth and yield parameters of maize and weeds were taken at flowering and harvest. The results indicated that there was a significant reduction in maize leaf area, leaf area index, and photosynthetically active radiation due to weed interference at both sites. The application of nitrogen at 90 kg N ha^-1 significantly increased maize leaf area. Reductions in maize growth and yield at flowering and harvest were significant due to weed interference at both Ikenne and Shika, thus showing that the reductions in maize growth and yield due to weed interference were not ecological zone specific even though weed species and their seed banks may differ. Ameliorative management options could thus be the same in the two agroecological zones. Application of 90 kg N ha^-1 led to a significant increase in maize grain yield at Shika while there was no fertilizer effect at Ikenne on grain yield. There was no significant difference between 60 and 90 kg N ha^-1, suggesting that 60 kg N ha^-1 could be a possible replacement for the higher fertilizer rate at least for the identified maize genotypes. Low weed pressure treatment led to 26% and 35% reductions in maize grain yield at Ikenne and Shika, respectively, while 22% and 51% reductions, respectively, were observed due to high weed pressure. Generally, maize grain yield was higher at Ikenne than Shika. The maize genotypes Low N pool C2 and ACR 8328 PIN C7 performed better than the other genotypes at Ikenne while the maize genotype Oba super II had the best performance at harvest at Shika. Application of nitrogen increased weed biomass at flowering at Ikenne. The maize grain yield was highest in the N-efficient genotypes, Oba super II and Low N pool C2; the susceptible genotype TZB-SR had the least yield at Shika. There existed a negative and significant correlation between maize grain yield and weed biomass at both sites.
基金Supported by Major Projects of Seed Innovation Program in Chongqing City(CSTC2012ggc80002)~~
文摘According to seed production practice, the seed production techniques for BenIiangyou 3113, a new two-Iine hybrid rice combination, were summarized. In or-der to obtaln high and stabIe yielding, the seed production of BenIiangyou 3113 re-quires appropriate site seIection, rational sowing period, rational ratio between parental Iines, enhanced water and fertiIizer management, appropriate Ieaf cutting, strict weeding, good artificial poI ination and good pests and diseases controI.
文摘Hybrid rice technology in China was developed in three stages. From the 1950s onwards, hybrid rice researchers, as typified by Yuan Longping, sought out a feasible approach to utilizing rice heterosis, and developed the three-line indica hybrid rice. Led by the government, the hybrid rice technology R&D teams adopted the research mode of "large-scale cooperation"(大协作), and accomplished technical innovations in the three-line system, selective breeding, and production of hybrid seeds. In the ensuing decade, Yuan Longping and others discovered the photo-thermo sensitive genic male sterility(PTGMS) of rice and developed PTGMS lines, turning highly advantageous two-line rice breeding from scientific vision into reality. Over the next twenty-five years, China’s super-rice breeding program integrated the conventional, three-line, and two-line breeding methods with modern molecular biotechnology methods. For nearly half a century, China made outstanding attainments in acquiring quality strains that yielded enormous economic and social benefits. Throughout this process, factors such as urgent social demand for increased grain production and scientific research cooperation provided significant impetus.
基金Supported by Guizhou Modern Agricultural(rice)Industry System(GZCYTX2014-06002)~~
文摘Chuanxiang No.2058 is a new combination of three-line late indica hybrid rice bred based on sterile line Chuanxiang 29A and restorer Qiannanhui No.2058. In order to promote its application, seed production techniques of Chuanxiang No.2058 were explored during 2009-2010. The research detailed the seed production tech- niques from selection of seed production bases, rational arrangement of sowing gap stage, seedling cultivation in different stages, scientific arrangement of male/female parents, management of fertilizer and water, adjustment of florescence, artificial pol- lination, comprehensive treatment of disease and pest damages, and timely control- ling of abnormal and poorly-qualified rice.
基金Supported by National Agricultural Scientific Achievement Transformation Project(2014D20000131)Science and Technology Program from Technology Bureau of Chande City(2013N156)~~
文摘High-quality hybrid rape Changzayou 3 is a new yellow-seed double-low rape variety with high yield, good resistance to diseases and lodging and high oil content, suitable for winter cropping in central China. Its high-yield cultivation tech- niques are mainly early seeding at proper time, thinning timely, rational close planting, scientific fertilization, control of diseases and pest and weeding.
文摘Augmented randomized complete block test was conducted to evaluate the heterosis of 80 hybrid combinations from TGMS line 402S and its original parent Xiangyou 91S,and the combining a-bility of 40 testcrossing lines.The results of identification test showed that among 47 combinations yielding over the control Xiangyou 15,17 ones with 402S and 3 ones with Xiangyou 91S overyielded more than 20%,reaching the significant level of 1 %;and among 51 combinations yielding over their corresponding higher yield parents,18 ones with 402S and 9 ones with Xiangyou 91S overyielded at 5% or 1% significant level.The test for the GCA effect of all parents indicated that 402S possessed a stronger combining ability than Xiangyou 91S on yield,ailiquae of main inflorescence,total siliquae per plant,seed yield of single plant and 1000 seed weight.10 testcrossing lines with high GCA were picked out for next testcrosses.Among 8 agronomic traits,total siliquae per plant and seed yield of single plant were regarded as the key selecting indexes according to the correlation analysis between yield and the agronomic traits on heterosis and on the GCA effect of all parents.
文摘This paper deals with the recent hybrid rice development in the Philippines and some information about developing economic and technical cooperation in hybrid rice between China and the Philippines.
