japonica rice is mainly distributed in Northeast China and accounts for 44.6% of the total cultivated area of japonica rice in China. The comprehensive using of inter-subspecies heterosis is the main breeding mode of ...japonica rice is mainly distributed in Northeast China and accounts for 44.6% of the total cultivated area of japonica rice in China. The comprehensive using of inter-subspecies heterosis is the main breeding mode of super japonica rice varieties in this region. Improving rice quality at relative high yielding level is the current research focus. Performing crosses between indica and japonica lines allows for the recombination of regulatory genes and genetic backgrounds, leading to complicated genetic rice quality characteristics, which can be used to explore patterns of quality improvement. In the present study, we utilize recombinant inbred lines （RILs） derived from indica-japonica hybridization to analyze the effect factors of rice quality derived from genetic factors, which contain both regulatory genes concerning rice quality and genetic backgrounds＇ random introduction frequency coming from indica （Di value）, and the improvement strategy was further discussed. The regulatory genes involved in amylase content （Wx） and nitrogen utilization efficiency （NRT1.1B） were the major factors affecting the amylose content （AC） and protein content （PC） in RILs, respectively. Both the Di value and the major grain width gene （GS5） had regulatory effects on milled rice width （MRW） in RILs, and their interaction explained the major variance of MRW in the RILs. With the mediation of MRW and chalkiness degree （C）, Di value had a further impact on head rice rate （HR）, which was relatively poor when the Di value was over 40%. In Northeast China, the Di value should be lowered by backcrossing or multiple crosses during the breeding of indica-japonica hybridization to maintain the whole better HR and further to emphasize the use of favorable genes in individual selection.展开更多
Research on hybrid rice in Jiangsu Province, China began in 1970. Great progress has been made since then, which can be divided into three stages according to the development of hybrid rice breeding and production in ...Research on hybrid rice in Jiangsu Province, China began in 1970. Great progress has been made since then, which can be divided into three stages according to the development of hybrid rice breeding and production in Jiangsu Province. The first stage was beginning stage from 1970 to 1980, when progress was mainly made in cytoplasmic male sterile line breeding. The second stage could be described as developing stage, from 1980 to 1995, when indica hybrid rice was rapidly popularized, and japonica hybrid rice became popular later. From 1996, hybrid rice breeding in Jiangsu Province entered the third stage, when both indica and japonica hybrid rice breeding in the three-line system or intersubspecific hybrid rice breeding in the two-line system made a great breakthrough with the successful breeding of the hybrids Feyou 559, 9 You 138 and Liangyoupeijiu. The developing trend of hybrid rice breeding in Jiangsu Province is also discussed.展开更多
indica and japonica are the two most important subspecies of Asian cultivated rice. Identifying mechanisms responsible for population differentiation in these subspecies is important for indica-japonica hybridization ...indica and japonica are the two most important subspecies of Asian cultivated rice. Identifying mechanisms responsible for population differentiation in these subspecies is important for indica-japonica hybridization breeding. In this study, subspecies and economic trait differentiation patterns were analyzed using morphological and molecular （InDel and Intron Length Polymorphism） data in F2 and F3 populations derived from indica-japonica hybridization. Populations were grown in Liaoning and Guangdong provinces, China, with F3 populations generated from F2 populations using bulk harvesting （BM） and single-seed descent methods （SSD）. Segregation distortion was detected in F3-BM populations, but not in F3- SSD or in F2 populations. Superior performance was observed with respect to economic traits in Liaoning compared with that in Guangdong and 1 000-grain weight （KW）, seed setting rate （SSR） and grain yield per plant （GYP） were significantly correlated with indica and japonica subspecies types. Analysis of molecular and morphological data demonstrated that the environment is the main factor giving rise to population differentiation in indica-japonica hybridization. In addition, we also found that KW, SSR and GYP are related to subspecies characteristics and kinship, which is possibly a significant factor resulting in economic trait differentiation and determining environmental adaptability. Our study has provided new insights into the process of population differentiation in these subspecies to inform indica-japonica hybridization breeding.展开更多
Two recombinant inbred line （RIL） populations, one derived from a cross between Zhongyouzao 8 （indica） and Toyonishiki （japonica） and the other from a cross between Qishanzhan （indica） and Akihikari （japonica...Two recombinant inbred line （RIL） populations, one derived from a cross between Zhongyouzao 8 （indica） and Toyonishiki （japonica） and the other from a cross between Qishanzhan （indica） and Akihikari （japonica）, were grown in Liaoning and Sichuan Provinces, China, to study the panicle type index （PTI, the ratio of a number of node position on panicle axis where the secondary branch with the most numerous secondary branch grains is located to the number of primary branches） and its relationships with subspecies characteristics and yield traits. With continuous distribution of PTI and numerous of lines with different PTIs in the progenies, indica-japonica hybridization could be a method for breeding cultivars with ideal panicle type. PTI was significantly influenced by environments, with a significant decrease from Liaoning to Sichuan A significantly negative correlation was found between PTI and most of subspecies characteristics. PTI varied remarkably with different subspecies types. As a whole, it showed a trend of indica （H）〉indicalinous （H＇）〉japonicalinous （K＇）〉japonica （K） However, it is not appropriate to regard PTI as a parameter for subspecies classification in rice because it was recombined in the filial generations of cross between indica and japonica rice. The negative correlations were found between PTI and most of panicle characteristics, as well as yield-related traits. Based on PTI, most of lines from the two populations were middle dominant panicle type （the number of grains on the secondary branch is numerous in middle position of the panicle） and lower dominant panicle type （the number of grains on the secondary branch is numerous in lower position of the panicle and becomes less towards the top of panicle） with significant yield advantages.展开更多
基金sponsored by the National Natural Science Foundation of China(31371587,31430062)the Cultivation Plan for Youth Agricultural Science Technology Innovative Talents of Liaoning Province,China(2015035,2015036)the Program for Changjiang Scholars and Innovative Research Team in University,China(IRT13079)
文摘japonica rice is mainly distributed in Northeast China and accounts for 44.6% of the total cultivated area of japonica rice in China. The comprehensive using of inter-subspecies heterosis is the main breeding mode of super japonica rice varieties in this region. Improving rice quality at relative high yielding level is the current research focus. Performing crosses between indica and japonica lines allows for the recombination of regulatory genes and genetic backgrounds, leading to complicated genetic rice quality characteristics, which can be used to explore patterns of quality improvement. In the present study, we utilize recombinant inbred lines （RILs） derived from indica-japonica hybridization to analyze the effect factors of rice quality derived from genetic factors, which contain both regulatory genes concerning rice quality and genetic backgrounds＇ random introduction frequency coming from indica （Di value）, and the improvement strategy was further discussed. The regulatory genes involved in amylase content （Wx） and nitrogen utilization efficiency （NRT1.1B） were the major factors affecting the amylose content （AC） and protein content （PC） in RILs, respectively. Both the Di value and the major grain width gene （GS5） had regulatory effects on milled rice width （MRW） in RILs, and their interaction explained the major variance of MRW in the RILs. With the mediation of MRW and chalkiness degree （C）, Di value had a further impact on head rice rate （HR）, which was relatively poor when the Di value was over 40%. In Northeast China, the Di value should be lowered by backcrossing or multiple crosses during the breeding of indica-japonica hybridization to maintain the whole better HR and further to emphasize the use of favorable genes in individual selection.
文摘Research on hybrid rice in Jiangsu Province, China began in 1970. Great progress has been made since then, which can be divided into three stages according to the development of hybrid rice breeding and production in Jiangsu Province. The first stage was beginning stage from 1970 to 1980, when progress was mainly made in cytoplasmic male sterile line breeding. The second stage could be described as developing stage, from 1980 to 1995, when indica hybrid rice was rapidly popularized, and japonica hybrid rice became popular later. From 1996, hybrid rice breeding in Jiangsu Province entered the third stage, when both indica and japonica hybrid rice breeding in the three-line system or intersubspecific hybrid rice breeding in the two-line system made a great breakthrough with the successful breeding of the hybrids Feyou 559, 9 You 138 and Liangyoupeijiu. The developing trend of hybrid rice breeding in Jiangsu Province is also discussed.
基金This Work is Supported by "The Trans-Century Training Program Foundation for Outstanding Individuals in Science and Technology" of the State Education Commission of China
基金supported by the National Natural Science Foundation of China (30971845)
文摘indica and japonica are the two most important subspecies of Asian cultivated rice. Identifying mechanisms responsible for population differentiation in these subspecies is important for indica-japonica hybridization breeding. In this study, subspecies and economic trait differentiation patterns were analyzed using morphological and molecular （InDel and Intron Length Polymorphism） data in F2 and F3 populations derived from indica-japonica hybridization. Populations were grown in Liaoning and Guangdong provinces, China, with F3 populations generated from F2 populations using bulk harvesting （BM） and single-seed descent methods （SSD）. Segregation distortion was detected in F3-BM populations, but not in F3- SSD or in F2 populations. Superior performance was observed with respect to economic traits in Liaoning compared with that in Guangdong and 1 000-grain weight （KW）, seed setting rate （SSR） and grain yield per plant （GYP） were significantly correlated with indica and japonica subspecies types. Analysis of molecular and morphological data demonstrated that the environment is the main factor giving rise to population differentiation in indica-japonica hybridization. In addition, we also found that KW, SSR and GYP are related to subspecies characteristics and kinship, which is possibly a significant factor resulting in economic trait differentiation and determining environmental adaptability. Our study has provided new insights into the process of population differentiation in these subspecies to inform indica-japonica hybridization breeding.
基金supported by the National Natural Science Foundation of China(GrantNo.30871468)the Young Teacher Scientific Research Fund of Shenyang Agricultural University,China(Grant No.20081001)
文摘Two recombinant inbred line （RIL） populations, one derived from a cross between Zhongyouzao 8 （indica） and Toyonishiki （japonica） and the other from a cross between Qishanzhan （indica） and Akihikari （japonica）, were grown in Liaoning and Sichuan Provinces, China, to study the panicle type index （PTI, the ratio of a number of node position on panicle axis where the secondary branch with the most numerous secondary branch grains is located to the number of primary branches） and its relationships with subspecies characteristics and yield traits. With continuous distribution of PTI and numerous of lines with different PTIs in the progenies, indica-japonica hybridization could be a method for breeding cultivars with ideal panicle type. PTI was significantly influenced by environments, with a significant decrease from Liaoning to Sichuan A significantly negative correlation was found between PTI and most of subspecies characteristics. PTI varied remarkably with different subspecies types. As a whole, it showed a trend of indica （H）〉indicalinous （H＇）〉japonicalinous （K＇）〉japonica （K） However, it is not appropriate to regard PTI as a parameter for subspecies classification in rice because it was recombined in the filial generations of cross between indica and japonica rice. The negative correlations were found between PTI and most of panicle characteristics, as well as yield-related traits. Based on PTI, most of lines from the two populations were middle dominant panicle type （the number of grains on the secondary branch is numerous in middle position of the panicle） and lower dominant panicle type （the number of grains on the secondary branch is numerous in lower position of the panicle and becomes less towards the top of panicle） with significant yield advantages.
