Rice is the staple food for more than half of the world＇s population and for more than 60% of China population. Increasing rice yield is therefore crucial for solving food shortage problem, ensuring food secruity, an...Rice is the staple food for more than half of the world＇s population and for more than 60% of China population. Increasing rice yield is therefore crucial for solving food shortage problem, ensuring food secruity, and reducing poverty. Given the vast population and limited per capita cultivated land in China, meeting food demands by increasing the yield per unit area with the aid of advanced sciences and technologies would be the only option. Several alternative measures for increasing crop yield, such as building water conservancy facilities, increasing fertilizer application, improving soil texture, forming interrelated cultivation techniques, more effective controlling of pests and diseases, and using of elite varieties, have been undertaken. Among these alternative measures, adopting elite varieties, particularly popularizing super hybrid rice, proves to be the most economical and effective option.展开更多
Rice （Oryza sativa L.） is originated from Asia and more than 90% of rice is produced inAsia. As the most important cereal crop in the world, rice is the staple food for over 1/3 global population, while this proport...Rice （Oryza sativa L.） is originated from Asia and more than 90% of rice is produced inAsia. As the most important cereal crop in the world, rice is the staple food for over 1/3 global population, while this proportion is over 60% in Asia （Wan 2010）. In order to maintain the most important role that rice has played in Asian agriculture and ensure food security in the world, especially in Asia,展开更多
Microsporogenesis and male gametogenesis are essential for the alternating life cycle of flowering plants between diploid sporophyte and haploid gametophyte generations. Rice （Oryza sativa） is the world＇s major sta...Microsporogenesis and male gametogenesis are essential for the alternating life cycle of flowering plants between diploid sporophyte and haploid gametophyte generations. Rice （Oryza sativa） is the world＇s major staple food, and manipulation of pollen fertility is particularly important for the demands to increase rice grain yield. Towards a better understanding of the mechanisms controlling rice male reproductive development, we describe here the cytological changes of anther development through 14 stages, including cell division, differentiation and degeneration of somatic tissues consisting of four concentric cell layers surrounding and supporting reproductive cells as they form mature pollen grains through meiosis and mitosis. Furthermore, we compare the morphological difference of anthers and pollen grains in both monocot rice and eudicot Arabidopsis thaliana. Additionally, we describe the key genes identified to date critical for rice anther development and pollen formation.展开更多
The developmental genetics of plant height was analyzed from two groups of three-line indica hybrid rice at two environmental conditions based on the NCII design, using the additive-dominant developmental genetics mod...The developmental genetics of plant height was analyzed from two groups of three-line indica hybrid rice at two environmental conditions based on the NCII design, using the additive-dominant developmental genetics models and the statistic methods. The results showed that the rice genotypes and environmental conditions could both affect plant height, and the effects of environment on plant height decreased gradually with plant development. Additive and dominant effects both governed the performance of plant height at all developmental stages. However, the degrees of effect varied among the rice genotypes. Moreover, the interaction between environments and genotypes also affected plant height. The genetic effects differed at most developmental stages. Furthermore, the expressJon of additive effect was more active than that of dominant effect. Conditional interaction effects with environment also influenced plant height during genetic development, especially at the eady stage. Mid-parent heterosis （HMP） increased gradually with the developmental stage of plant height, and maximized at the latest stage, whereas the heterosis over the better parent （HBP） showed small differences among the genotypes, and kept stable at the later stage, with positive numeric value. At most developmental stages, conditional HMP was positively significant, while conditional HBP was negatively significant. All above results suggest that HMP and HBP have some new expressions in all developmental periods and the levels and directions are quite different.展开更多
Following NCI design, the developmental genetic behavior of tiller number (TN) in three-line indica hybrid rice was studied using additive-dominance developmental genetic models and the corresponding statistical metho...Following NCI design, the developmental genetic behavior of tiller number (TN) in three-line indica hybrid rice was studied using additive-dominance developmental genetic models and the corresponding statistical methods. The results showed that dominance effects were predominant for TN. The expression of those additive effects were affected by environment and genotype interaction, but the expression of dominance effects were not affected. Heterosis was the strongest in the middle developmental periods of TN. Additive effects and dominance effects were selectively expressed throughout in the entire tillering developmental stage. Analysis of genetic correlation between TN at different stages and the productive panicles indicated that a close correlation appeared earlier in the populations with higher heterosis than in those with less heterosis. Utilization of heterosis at the middle tillering stage might enhance the final biomass but reduce the percentage of productive panicles.展开更多
Plant height （PH） is one of the most important agronomic traits of rice, as it directly affects the lodging resistance and the high yield potential. Meanwhile, PH is often constrained by water supply over the entire...Plant height （PH） is one of the most important agronomic traits of rice, as it directly affects the lodging resistance and the high yield potential. Meanwhile, PH is often constrained by water supply over the entire growth period. In this study, a recombinant inbred line （RIL） derived from Xiaobaijingzi and Kongyu 131 strains grown under drought stress and with normal irrigation over 2 yr （2013 and 2014）, respectively （regarded as four environments）, was used to dissect the genetic basis of PH by developmental dynamics QTL analysis combined with QTL^environment interactions. QTLs with net effects excluding the accumulated effects were detected to explore the relationship between genexgene interactions and genexenvironment interactions in specific growth period. A total of 26 additive QTLs （A-QTLs） and 37 epistatic QTLs （E-QTLs） associated with PH were detected by unconditional and conditional mapping over seven growth periods, qPH-2-3, qPH-4-3, qPH-6-1, qPH-7-1, and qPH-12-5 could be detected by both unconditional and conditional analyses, qPH-4-3 and qPH-7-5 were detected in four stages （periods） to be sequentially expressed QTLs controlling PH continuous variation. QTLs with additive effects （A-QTLs） were mostly expressed in the period $3iS2 （the time interval from stages 2 to 3）, and QTLxenvironment interactions performed actively in the first three stages （periods） which could be an important developmental period for rice to undergo external morphogenesis during drought stress. Several QTLs showed high adaptability for drought stress and many QTLs were closely related to the environments such as qPH-3-5, qPH-2-2 and qPH-6-1. 72.5% of the QTLs with a and aa effects detected by conditional analysis were under drought stress, and the PVE of QTLs detected by conditional analysis under drought stress were also much higher than that under normal irrigation. We infer that environments would influence the detection results and sequential expression of genes was highly influenced by environments as well. Many QTLs （qPH-1-2, qPH-3-5, qPH-4-1, qPH-2-3） coincident with previously identified drought resistance genes. The result of this study is helpful to elucidating the genetic mechanism and regulatory network underlying the development of PH in rice and providing references to marker assisted selection.展开更多
The developmental genetic behaviors of brown rice width （BRW） have been studied in indica-japonica hybrid rice （Oryza sativa L.）, in which seven indica male sterile lines and five japonica restorer lines were appl...The developmental genetic behaviors of brown rice width （BRW） have been studied in indica-japonica hybrid rice （Oryza sativa L.）, in which seven indica male sterile lines and five japonica restorer lines were applied, by using the developmental genetic models and corresponding statistical approaches for quantitative traits of triploid in cereal crops. The BRW of indica-japonica hybrid rice was co-determined by gene expression of tdploid endosperm, cytoplasm, diploid maternal plant and their genotype × environmental interaction effects. Unconditional analysis showed that the endosperm additive and matemal additive effects were predominant for the development of BRW from early- to late-stage of the grain development, but the endosperm dominant effect together with matemal effect and cytoplasmic effect became the major factor determing the BRW at the ripening stage. Moreover, conditional analysis found that there were new onset and offset of gene expression at different developmental stages of BRW in indica-japonica hybrid rice. Maternal and cytoplasm general heritabilities and their interaction heritabilities were more important compared to other components of heritability for BRW at all the five developmental stages.展开更多
The purpose of this study was to identify the existing rice breeding programs in Myanmar and to determine researchers＇ attitudes on hybrid rice research mid its determinmlts. A sample consists of 56 researchers who a...The purpose of this study was to identify the existing rice breeding programs in Myanmar and to determine researchers＇ attitudes on hybrid rice research mid its determinmlts. A sample consists of 56 researchers who are working in Department of Agricultural Research, Department of Agriculture and Yezin Agricultural University, and involving varietal development of hybrid rice. The research instruments were a questionnaire used by 4 points Likert scale of strongly agree, agree, less agree and not agree to measure on researchers＇ attitudes towards 14 determinants of varietal development of hybrid rice production. The study revealed that the average age of the researchers was 46.5 years ranged from 25 to 60 years. The majority of researchers were 51-60 years old （41.1%）. The working experience of researchers ranged from 5 to 36 years and the metal of their experience was 20 years. The educational level was Ph.D. （35.7%）, M.Agr.Sc. （26.8%）, and B.Agr.Sc. （37.5%）. Majority of researchers were female （76.8%） and 58.9% were rice breeders. Moreover, 48.2% of researchers obtained the hybrid rice technology from breeding training and the researchers who believed in their current breeding works were 51.8%. Among 33 rice breeders, 72.7% of the rice breeders applied only convention breeding method. In addition, researchers＇ opinions on farmer＇s perception of hybrid rice technology, 60.7% of the researchers agreed on inferior grain quality and 73.2% of researchers strongly agreed on not stable market. This study found out more thin1 half of the researchers strongly agreed on 10 out of 14 determinmlts such as poor infrastructure, low human resource development, parental problem, insufficient experience, limit germplasm resource, limit research facilities, no incentive for breeders, weak public-private partnership, fewer quality breeders and not enough research fund. Moreover, half of the researchers agreed on 3 determinants likely need special technical training, need international assistance and climate change challenges. Finally, development of hybrid rice research in Mymlmar, there will be needed international assistmlce, and upgraded to hybrid rice research center from currently hybrid rice research section and need integrated hybrid rice policy supported by government.展开更多
A male sterile mutant plant was found from the rice field of the local rice variety which was cultivated for a long time in the west of Hubei Province. The plant has more vigorous tillering ability. Its plant height o...A male sterile mutant plant was found from the rice field of the local rice variety which was cultivated for a long time in the west of Hubei Province. The plant has more vigorous tillering ability. Its plant height of 95 cm was a bit shorter than that of the normal ones. The plant type, the leaf shape and the color of leaf sheath and glume tip of this mutant were identieal to that of the normal plant whereas the color of arrowhead-shape anther was milky white. This mutant set no seed during self-pollination. When it was crossed with IR24. IR26, Minhui 63 or Xieqing-zaoxuian. the Ffertilities were normal. The fertility of this mutant could be restored by IR24, IR26 and Minhui 63 and maintained by Xieqing-zaoxian. Maxie A was developed in 1987 by the successive backcrossing of the mutant with Xieqing-zaoxian. The percentage of abortive pollen in Maxie A in uninucleate microspore to early binucleate microspore stage is展开更多
We studied the relationship between the head-ing sensitivity and the male-sterile sensitivityin photoperiod-sensitive genie males-sterile rice(PGMSR)and conventional rice.Materialsused in this study were 7001S,a late ...We studied the relationship between the head-ing sensitivity and the male-sterile sensitivityin photoperiod-sensitive genie males-sterile rice(PGMSR)and conventional rice.Materialsused in this study were 7001S,a late maturingPGMS japonica strain derived from Nongken58S; Akihikari and Youmang-zaojing(YMZJ),two early maturing conventional Japonica rice;and CPSLO-17,a Wide compatible convention-al indica rice.The heading date and seed-set-ting rate of Fand Fof three cross combina-tions between PGMSR and conventional riceswere examined in phytotron which was adjust-ed at 25±1℃ with day-length of 14.5 h(LD)and 12 h(SD).The segregation ratio of fertile:sterile in Funder LD was in accordance展开更多
China is the biggest country of rice production and consumption in the world;more than 50% of the population feeds chiefly on rice. The quality of rice and its role as a staplefood carry much weight. The rice qualitie...China is the biggest country of rice production and consumption in the world;more than 50% of the population feeds chiefly on rice. The quality of rice and its role as a staplefood carry much weight. The rice qualities are those aspects concerning processing, appearance,cooking, nutrition and safety of the product. The study, formulation and implementation of standardson rice qualities and testing bear heavily on the improving of rice qualities, human health,substitution of rice varieties, promoting quality rice production and regulating rice market.展开更多
Field experiments were carried out in northern Zhejiang Province. Three insecticides (methamidophos,Shachongshuang and triazophos) were used to control the rice leaffolder Cnaphalocrocis medinalis and rice striped ste...Field experiments were carried out in northern Zhejiang Province. Three insecticides (methamidophos,Shachongshuang and triazophos) were used to control the rice leaffolder Cnaphalocrocis medinalis and rice striped stemborer Chilo suppressalis in rice fields during 18—27 days after transplantating. The impacts of timing and insecticides on the population development of brown planthopper Nilaparavata lugens was surveyed by direct counting on the plants or by tapping method.展开更多
Conventional machine harvesting involves cut-ting, collecting, transporting operation beforethe grain is threshed (Cutting prior to thresh-ing-CPT), and the handling of quantity ofstraw. The stripper harvesting system...Conventional machine harvesting involves cut-ting, collecting, transporting operation beforethe grain is threshed (Cutting prior to thresh-ing-CPT), and the handling of quantity ofstraw. The stripper harvesting system stripsthe grain as well as small scraps of leaves and展开更多
Genetic control of leucine content in indica-japonica hybrid rice (Oryza sativa L.) was studied in 35 crosses of F1 and F2 generations, which were derived from crossing 7 male sterile indica rice lines with 5 restorer...Genetic control of leucine content in indica-japonica hybrid rice (Oryza sativa L.) was studied in 35 crosses of F1 and F2 generations, which were derived from crossing 7 male sterile indica rice lines with 5 restorer japonica rice lines along with their parents. Two genetic models and their corresponding statistical methods for quantitative traits of triploid seeds in cereal crops were used for the analysis. The first was the unconditional genetic model, which refers to the analysis of cumulative measurements (from flowering to a specific time) along the developmental stages, while the second was the conditional genetic model, which relates to analysis from one developmental stage to another stage (t - 1→t). The results showed that leucine content of indica-japonica hybrid rice was controlled by the expression of triploid endosperm effect (endosperm additive effect and endosperm dominant effect), cytoplasm effect, diploid maternal plant effect (maternal additive effect and maternal dominant effect) and their environmental interaction effects. Of these effects, endosperm dominant effect and maternal dominant effect were more important at the earlier stages, while endosperm additive effect and maternal additive effect were more important at the later stages of rice grain development under both unconditional and conditional genetic analyses. Due to the high heritabilities, which came from endosperm, maternal and cytoplasm effects for leucine content at different developmental stages, selection for leucine content of indica-japonica hybrid rice would be more efficient at early generations in breeding programs.展开更多
Many studies have reported that polyamines have an effect on a number of growth and developmental process in plants, such as cell division, embryogenesis, senescense, and flowering. However, there are few reports on t...Many studies have reported that polyamines have an effect on a number of growth and developmental process in plants, such as cell division, embryogenesis, senescense, and flowering. However, there are few reports on the physiological significance in of polyamines grain filling of rice. We studied the level of polyamines in the developing grains and their relations with grain filling and grain weight, using 8 rice varieties including hybrid combinations. It was showed that the content of Put (puterscine), Spd (spermidine), and Spm (spermine), especially Spd and Spm, was展开更多
K You 48-2 is a new combination of early hybrid rice with good grain quality and high yield, developed by combining male sterile line K-Qing A having japonica cytoplasm and indica genome and restorer line Ce 48-2. In ...K You 48-2 is a new combination of early hybrid rice with good grain quality and high yield, developed by combining male sterile line K-Qing A having japonica cytoplasm and indica genome and restorer line Ce 48-2. In the regional trial of Hubei Province in 1991, its yield was 4.4% higher than that of the CK Weiyou 48-2, being significant at 0.05 level. In the same year, in another regional trial of Sichuan Province, its yield was 8.9% higher than that of the CK Weiyou 48-2, being significant at 0.01 level. It has the highest yield among all tested varieties in both provincial trials. It has shown good grain quality with 60% head rice recovery and moderate resistance to rice blast.展开更多
1996 is the first year for realizing the object of fish culture in 66,600 ha of rice field in Zhejiang Province. The provincial government has appropriated $ 24,000 per ha for starting capital. Starting from this year...1996 is the first year for realizing the object of fish culture in 66,600 ha of rice field in Zhejiang Province. The provincial government has appropriated $ 24,000 per ha for starting capital. Starting from this year, counties with the tradition of fish culture in rice fields as Youngjia and Qingtian have put stress on popularizing the new technique of fish culture in ditches and puddles to raise the yield for per unit area. In areas of Central Zhejiang and North Zhejiang with hilly land and plain area with double—season rice, people have changed traditional fish varieties into special and excellent fish varieties.展开更多
文摘Rice is the staple food for more than half of the world＇s population and for more than 60% of China population. Increasing rice yield is therefore crucial for solving food shortage problem, ensuring food secruity, and reducing poverty. Given the vast population and limited per capita cultivated land in China, meeting food demands by increasing the yield per unit area with the aid of advanced sciences and technologies would be the only option. Several alternative measures for increasing crop yield, such as building water conservancy facilities, increasing fertilizer application, improving soil texture, forming interrelated cultivation techniques, more effective controlling of pests and diseases, and using of elite varieties, have been undertaken. Among these alternative measures, adopting elite varieties, particularly popularizing super hybrid rice, proves to be the most economical and effective option.
文摘Rice （Oryza sativa L.） is originated from Asia and more than 90% of rice is produced inAsia. As the most important cereal crop in the world, rice is the staple food for over 1/3 global population, while this proportion is over 60% in Asia （Wan 2010）. In order to maintain the most important role that rice has played in Asian agriculture and ensure food security in the world, especially in Asia,
基金supported by the funds from the National Basic Research Program of China(Nos.2009CB941500 and 2007CB108700)the National Natural Science Foundation of China(No.30725022)+1 种基金the Chinese Transgenic Project(No. 2009ZX08009-108B)the National 863 High-Tech Project (No.2011AA10A101)
文摘Microsporogenesis and male gametogenesis are essential for the alternating life cycle of flowering plants between diploid sporophyte and haploid gametophyte generations. Rice （Oryza sativa） is the world＇s major staple food, and manipulation of pollen fertility is particularly important for the demands to increase rice grain yield. Towards a better understanding of the mechanisms controlling rice male reproductive development, we describe here the cytological changes of anther development through 14 stages, including cell division, differentiation and degeneration of somatic tissues consisting of four concentric cell layers surrounding and supporting reproductive cells as they form mature pollen grains through meiosis and mitosis. Furthermore, we compare the morphological difference of anthers and pollen grains in both monocot rice and eudicot Arabidopsis thaliana. Additionally, we describe the key genes identified to date critical for rice anther development and pollen formation.
基金supported by the National Natural Science Foundation of China(Grant No. 30370865) and the Innovation Projects of New Plant and Animal Breeding in Chongqing Municipality, China
文摘The developmental genetics of plant height was analyzed from two groups of three-line indica hybrid rice at two environmental conditions based on the NCII design, using the additive-dominant developmental genetics models and the statistic methods. The results showed that the rice genotypes and environmental conditions could both affect plant height, and the effects of environment on plant height decreased gradually with plant development. Additive and dominant effects both governed the performance of plant height at all developmental stages. However, the degrees of effect varied among the rice genotypes. Moreover, the interaction between environments and genotypes also affected plant height. The genetic effects differed at most developmental stages. Furthermore, the expressJon of additive effect was more active than that of dominant effect. Conditional interaction effects with environment also influenced plant height during genetic development, especially at the eady stage. Mid-parent heterosis （HMP） increased gradually with the developmental stage of plant height, and maximized at the latest stage, whereas the heterosis over the better parent （HBP） showed small differences among the genotypes, and kept stable at the later stage, with positive numeric value. At most developmental stages, conditional HMP was positively significant, while conditional HBP was negatively significant. All above results suggest that HMP and HBP have some new expressions in all developmental periods and the levels and directions are quite different.
文摘Following NCI design, the developmental genetic behavior of tiller number (TN) in three-line indica hybrid rice was studied using additive-dominance developmental genetic models and the corresponding statistical methods. The results showed that dominance effects were predominant for TN. The expression of those additive effects were affected by environment and genotype interaction, but the expression of dominance effects were not affected. Heterosis was the strongest in the middle developmental periods of TN. Additive effects and dominance effects were selectively expressed throughout in the entire tillering developmental stage. Analysis of genetic correlation between TN at different stages and the productive panicles indicated that a close correlation appeared earlier in the populations with higher heterosis than in those with less heterosis. Utilization of heterosis at the middle tillering stage might enhance the final biomass but reduce the percentage of productive panicles.
基金supported by the National Key Technologies R&D Program of China during the 12th Five-Year Plan period (2013BAD20B04)
文摘Plant height （PH） is one of the most important agronomic traits of rice, as it directly affects the lodging resistance and the high yield potential. Meanwhile, PH is often constrained by water supply over the entire growth period. In this study, a recombinant inbred line （RIL） derived from Xiaobaijingzi and Kongyu 131 strains grown under drought stress and with normal irrigation over 2 yr （2013 and 2014）, respectively （regarded as four environments）, was used to dissect the genetic basis of PH by developmental dynamics QTL analysis combined with QTL^environment interactions. QTLs with net effects excluding the accumulated effects were detected to explore the relationship between genexgene interactions and genexenvironment interactions in specific growth period. A total of 26 additive QTLs （A-QTLs） and 37 epistatic QTLs （E-QTLs） associated with PH were detected by unconditional and conditional mapping over seven growth periods, qPH-2-3, qPH-4-3, qPH-6-1, qPH-7-1, and qPH-12-5 could be detected by both unconditional and conditional analyses, qPH-4-3 and qPH-7-5 were detected in four stages （periods） to be sequentially expressed QTLs controlling PH continuous variation. QTLs with additive effects （A-QTLs） were mostly expressed in the period $3iS2 （the time interval from stages 2 to 3）, and QTLxenvironment interactions performed actively in the first three stages （periods） which could be an important developmental period for rice to undergo external morphogenesis during drought stress. Several QTLs showed high adaptability for drought stress and many QTLs were closely related to the environments such as qPH-3-5, qPH-2-2 and qPH-6-1. 72.5% of the QTLs with a and aa effects detected by conditional analysis were under drought stress, and the PVE of QTLs detected by conditional analysis under drought stress were also much higher than that under normal irrigation. We infer that environments would influence the detection results and sequential expression of genes was highly influenced by environments as well. Many QTLs （qPH-1-2, qPH-3-5, qPH-4-1, qPH-2-3） coincident with previously identified drought resistance genes. The result of this study is helpful to elucidating the genetic mechanism and regulatory network underlying the development of PH in rice and providing references to marker assisted selection.
文摘The developmental genetic behaviors of brown rice width （BRW） have been studied in indica-japonica hybrid rice （Oryza sativa L.）, in which seven indica male sterile lines and five japonica restorer lines were applied, by using the developmental genetic models and corresponding statistical approaches for quantitative traits of triploid in cereal crops. The BRW of indica-japonica hybrid rice was co-determined by gene expression of tdploid endosperm, cytoplasm, diploid maternal plant and their genotype × environmental interaction effects. Unconditional analysis showed that the endosperm additive and matemal additive effects were predominant for the development of BRW from early- to late-stage of the grain development, but the endosperm dominant effect together with matemal effect and cytoplasmic effect became the major factor determing the BRW at the ripening stage. Moreover, conditional analysis found that there were new onset and offset of gene expression at different developmental stages of BRW in indica-japonica hybrid rice. Maternal and cytoplasm general heritabilities and their interaction heritabilities were more important compared to other components of heritability for BRW at all the five developmental stages.
文摘The purpose of this study was to identify the existing rice breeding programs in Myanmar and to determine researchers＇ attitudes on hybrid rice research mid its determinmlts. A sample consists of 56 researchers who are working in Department of Agricultural Research, Department of Agriculture and Yezin Agricultural University, and involving varietal development of hybrid rice. The research instruments were a questionnaire used by 4 points Likert scale of strongly agree, agree, less agree and not agree to measure on researchers＇ attitudes towards 14 determinants of varietal development of hybrid rice production. The study revealed that the average age of the researchers was 46.5 years ranged from 25 to 60 years. The majority of researchers were 51-60 years old （41.1%）. The working experience of researchers ranged from 5 to 36 years and the metal of their experience was 20 years. The educational level was Ph.D. （35.7%）, M.Agr.Sc. （26.8%）, and B.Agr.Sc. （37.5%）. Majority of researchers were female （76.8%） and 58.9% were rice breeders. Moreover, 48.2% of researchers obtained the hybrid rice technology from breeding training and the researchers who believed in their current breeding works were 51.8%. Among 33 rice breeders, 72.7% of the rice breeders applied only convention breeding method. In addition, researchers＇ opinions on farmer＇s perception of hybrid rice technology, 60.7% of the researchers agreed on inferior grain quality and 73.2% of researchers strongly agreed on not stable market. This study found out more thin1 half of the researchers strongly agreed on 10 out of 14 determinmlts such as poor infrastructure, low human resource development, parental problem, insufficient experience, limit germplasm resource, limit research facilities, no incentive for breeders, weak public-private partnership, fewer quality breeders and not enough research fund. Moreover, half of the researchers agreed on 3 determinants likely need special technical training, need international assistance and climate change challenges. Finally, development of hybrid rice research in Mymlmar, there will be needed international assistmlce, and upgraded to hybrid rice research center from currently hybrid rice research section and need integrated hybrid rice policy supported by government.
文摘A male sterile mutant plant was found from the rice field of the local rice variety which was cultivated for a long time in the west of Hubei Province. The plant has more vigorous tillering ability. Its plant height of 95 cm was a bit shorter than that of the normal ones. The plant type, the leaf shape and the color of leaf sheath and glume tip of this mutant were identieal to that of the normal plant whereas the color of arrowhead-shape anther was milky white. This mutant set no seed during self-pollination. When it was crossed with IR24. IR26, Minhui 63 or Xieqing-zaoxuian. the Ffertilities were normal. The fertility of this mutant could be restored by IR24, IR26 and Minhui 63 and maintained by Xieqing-zaoxian. Maxie A was developed in 1987 by the successive backcrossing of the mutant with Xieqing-zaoxian. The percentage of abortive pollen in Maxie A in uninucleate microspore to early binucleate microspore stage is
文摘We studied the relationship between the head-ing sensitivity and the male-sterile sensitivityin photoperiod-sensitive genie males-sterile rice(PGMSR)and conventional rice.Materialsused in this study were 7001S,a late maturingPGMS japonica strain derived from Nongken58S; Akihikari and Youmang-zaojing(YMZJ),two early maturing conventional Japonica rice;and CPSLO-17,a Wide compatible convention-al indica rice.The heading date and seed-set-ting rate of Fand Fof three cross combina-tions between PGMSR and conventional riceswere examined in phytotron which was adjust-ed at 25±1℃ with day-length of 14.5 h(LD)and 12 h(SD).The segregation ratio of fertile:sterile in Funder LD was in accordance
文摘China is the biggest country of rice production and consumption in the world;more than 50% of the population feeds chiefly on rice. The quality of rice and its role as a staplefood carry much weight. The rice qualities are those aspects concerning processing, appearance,cooking, nutrition and safety of the product. The study, formulation and implementation of standardson rice qualities and testing bear heavily on the improving of rice qualities, human health,substitution of rice varieties, promoting quality rice production and regulating rice market.
文摘Field experiments were carried out in northern Zhejiang Province. Three insecticides (methamidophos,Shachongshuang and triazophos) were used to control the rice leaffolder Cnaphalocrocis medinalis and rice striped stemborer Chilo suppressalis in rice fields during 18—27 days after transplantating. The impacts of timing and insecticides on the population development of brown planthopper Nilaparavata lugens was surveyed by direct counting on the plants or by tapping method.
文摘Conventional machine harvesting involves cut-ting, collecting, transporting operation beforethe grain is threshed (Cutting prior to thresh-ing-CPT), and the handling of quantity ofstraw. The stripper harvesting system stripsthe grain as well as small scraps of leaves and
文摘Genetic control of leucine content in indica-japonica hybrid rice (Oryza sativa L.) was studied in 35 crosses of F1 and F2 generations, which were derived from crossing 7 male sterile indica rice lines with 5 restorer japonica rice lines along with their parents. Two genetic models and their corresponding statistical methods for quantitative traits of triploid seeds in cereal crops were used for the analysis. The first was the unconditional genetic model, which refers to the analysis of cumulative measurements (from flowering to a specific time) along the developmental stages, while the second was the conditional genetic model, which relates to analysis from one developmental stage to another stage (t - 1→t). The results showed that leucine content of indica-japonica hybrid rice was controlled by the expression of triploid endosperm effect (endosperm additive effect and endosperm dominant effect), cytoplasm effect, diploid maternal plant effect (maternal additive effect and maternal dominant effect) and their environmental interaction effects. Of these effects, endosperm dominant effect and maternal dominant effect were more important at the earlier stages, while endosperm additive effect and maternal additive effect were more important at the later stages of rice grain development under both unconditional and conditional genetic analyses. Due to the high heritabilities, which came from endosperm, maternal and cytoplasm effects for leucine content at different developmental stages, selection for leucine content of indica-japonica hybrid rice would be more efficient at early generations in breeding programs.
文摘Many studies have reported that polyamines have an effect on a number of growth and developmental process in plants, such as cell division, embryogenesis, senescense, and flowering. However, there are few reports on the physiological significance in of polyamines grain filling of rice. We studied the level of polyamines in the developing grains and their relations with grain filling and grain weight, using 8 rice varieties including hybrid combinations. It was showed that the content of Put (puterscine), Spd (spermidine), and Spm (spermine), especially Spd and Spm, was
文摘K You 48-2 is a new combination of early hybrid rice with good grain quality and high yield, developed by combining male sterile line K-Qing A having japonica cytoplasm and indica genome and restorer line Ce 48-2. In the regional trial of Hubei Province in 1991, its yield was 4.4% higher than that of the CK Weiyou 48-2, being significant at 0.05 level. In the same year, in another regional trial of Sichuan Province, its yield was 8.9% higher than that of the CK Weiyou 48-2, being significant at 0.01 level. It has the highest yield among all tested varieties in both provincial trials. It has shown good grain quality with 60% head rice recovery and moderate resistance to rice blast.
文摘1996 is the first year for realizing the object of fish culture in 66,600 ha of rice field in Zhejiang Province. The provincial government has appropriated $ 24,000 per ha for starting capital. Starting from this year, counties with the tradition of fish culture in rice fields as Youngjia and Qingtian have put stress on popularizing the new technique of fish culture in ditches and puddles to raise the yield for per unit area. In areas of Central Zhejiang and North Zhejiang with hilly land and plain area with double—season rice, people have changed traditional fish varieties into special and excellent fish varieties.
