The age, growth, and mortality of Gymnocypris firmispinatus were studied by 582 individuals that collected between July 2015 and June 2016 from the tributaries of the Anning River, China. The total length (TL) ranged ...The age, growth, and mortality of Gymnocypris firmispinatus were studied by 582 individuals that collected between July 2015 and June 2016 from the tributaries of the Anning River, China. The total length (TL) ranged from 27 mm to 242 mm, total weight (W) ranged from 0.2 g to 148.2 g. The relationship of total length and weight was expressed as W =7.754×10^-6 TL^ 3.304 for the total samples. The age classes of males were 1–9 a, and that of females were 1–13 a. The von Bertalanff y functions based on otolith readings and observed length data were L t ♂=198.6(1–e^-0.094 ( t +3.497)), and L t ♀=289.3(1–e^-0.089 ( t +1.109)). The total mortality ( Z ) of male and female G . firmispinatus was estimated as 0.73/a and 0.40/a, respectively. The natural mortality ( M ) was evaluated as 0.25/a for males and 0.20/a for females, fishing mortality ( F ) was 0.35/a for males and 0.16/a for females. The exploitation ratio of the population was 0.66/a for males and 0.50/a for females. It was concluded that the growth of the fish is relatively slower than other congeneric fishes. The population of G . firmispinatus in the tributaries of the Anning River might be in over-exploitation under the current fishing intensity.展开更多
Deep rooting is an important trait in rice drought resistance.Genetic resources of deep-rooting varieties are valuable in breeding of water-saving and drought-resistant rice.In the present study,234BC2F7 backcross int...Deep rooting is an important trait in rice drought resistance.Genetic resources of deep-rooting varieties are valuable in breeding of water-saving and drought-resistant rice.In the present study,234BC2F7 backcross introgression lines were derived from a cross of Dongye 80(an accession of Dongxiang wild rice as the donor parent)and R974(an indica restorer line as the recurrent parent).A genetic linkage map containing 1977 bin markers was constructed by ddRADSeq for QTL analysis.Thirty-one QTLs for four root traits(the number of deep roots,the number of shallow roots,the total number of deep roots and the ratio of deep roots)were assessed on six rice chromosomes in two environments(2020 Shanghai and 2021 Hainan).Two of the QTLs,qDR5.1 and qTR5.2,were located on chromosome 5 in a 70-kb interval.They were detected in both environments.qDR5.1 explained 13.35%of the phenotypic variance in 2020 Shanghai and 12.01%of the phenotypic variance in 2021 Hainan.qTR5.2 accounted for 10.88%and 10.93%of the phenotypic variance,respectively.One QTL(qRDR2.2)for the ratio of deep roots was detected on chromosome 2 in a 210-kb interval and accounted for 6.72%of the phenotypic variance in 2020.The positive effects of these three QTLs were all from Dongxiang wild rice.Furthermore,nine and four putative candidate genes were identified in qRDR2.2 and qDR5.1/qTR5.2,respectively.These findings added to our knowledge of the genetic control of root traits in rice.In addition,this study will facilitate the future isolation of candidate genes of the deep-rooting trait and the utilization of Dongxiang wild rice in the improvement of rice drought resistance.展开更多
Survivability is used to evaluate the ability of the satellite to complete the mission after failure,while the duration of maintaining performance is often ignored.An effective backup strategy can restore the constell...Survivability is used to evaluate the ability of the satellite to complete the mission after failure,while the duration of maintaining performance is often ignored.An effective backup strategy can restore the constellation performance timely,and maintain good network communication performance in case of satellite failure.From the perspective of network utility,the low Earth orbit(LEO)satellite constellation survivable graphical eva-luation and review technology(GERT)network with backup satel-lites is constructed.A network utility transfer function algorithm based on moment generating function and Mason formula is proposed,the network survivability evaluation models of on-orbit backup strategy and ground backup strategy are established.The survivable GERT model can deduce the expected mainte-nance time of LEO satellite constellation under different fault states and the network utility generated during the state mainte-nance period.The case analysis shows that the proposed surviv-able GERT model can consider the satellite failure rate,backup satellite replacement rate,maneuver control replacement ability and life requirement,and effectively determine the optimal sur-vivable backup strategy for LEO satellite constellation with limi-ted resources according to the expected network utility.展开更多
基金Supported by the Central Public-Interest Scientific Institution Basal Research Fund,CAFS(No.2016JBF0303)the National Non-Profit Institute Research Grant of Freshwater Fisheries Research Center,CAFS(No.2015JBFM38)
文摘The age, growth, and mortality of Gymnocypris firmispinatus were studied by 582 individuals that collected between July 2015 and June 2016 from the tributaries of the Anning River, China. The total length (TL) ranged from 27 mm to 242 mm, total weight (W) ranged from 0.2 g to 148.2 g. The relationship of total length and weight was expressed as W =7.754×10^-6 TL^ 3.304 for the total samples. The age classes of males were 1–9 a, and that of females were 1–13 a. The von Bertalanff y functions based on otolith readings and observed length data were L t ♂=198.6(1–e^-0.094 ( t +3.497)), and L t ♀=289.3(1–e^-0.089 ( t +1.109)). The total mortality ( Z ) of male and female G . firmispinatus was estimated as 0.73/a and 0.40/a, respectively. The natural mortality ( M ) was evaluated as 0.25/a for males and 0.20/a for females, fishing mortality ( F ) was 0.35/a for males and 0.16/a for females. The exploitation ratio of the population was 0.66/a for males and 0.50/a for females. It was concluded that the growth of the fish is relatively slower than other congeneric fishes. The population of G . firmispinatus in the tributaries of the Anning River might be in over-exploitation under the current fishing intensity.
基金supported by the National Modern Agricultural Industry Technology System Construction Program of China(Grant No.20212BBF63001)the Open Competition Program of Jiangxi Provincial Science and Technology in China(Grant No.20213AAF01001)+2 种基金the Jiangxi Provincial Science and Technology Support Program in China(Grant No.20203BBF63033)the Jiangxi Modern Agricultural Research Collaborative Innovation Project in China(Grant No.JXXTCX202111)the Open Project of State Key Laboratory of Rice Biology in China(Grant No.20200101)。
文摘Deep rooting is an important trait in rice drought resistance.Genetic resources of deep-rooting varieties are valuable in breeding of water-saving and drought-resistant rice.In the present study,234BC2F7 backcross introgression lines were derived from a cross of Dongye 80(an accession of Dongxiang wild rice as the donor parent)and R974(an indica restorer line as the recurrent parent).A genetic linkage map containing 1977 bin markers was constructed by ddRADSeq for QTL analysis.Thirty-one QTLs for four root traits(the number of deep roots,the number of shallow roots,the total number of deep roots and the ratio of deep roots)were assessed on six rice chromosomes in two environments(2020 Shanghai and 2021 Hainan).Two of the QTLs,qDR5.1 and qTR5.2,were located on chromosome 5 in a 70-kb interval.They were detected in both environments.qDR5.1 explained 13.35%of the phenotypic variance in 2020 Shanghai and 12.01%of the phenotypic variance in 2021 Hainan.qTR5.2 accounted for 10.88%and 10.93%of the phenotypic variance,respectively.One QTL(qRDR2.2)for the ratio of deep roots was detected on chromosome 2 in a 210-kb interval and accounted for 6.72%of the phenotypic variance in 2020.The positive effects of these three QTLs were all from Dongxiang wild rice.Furthermore,nine and four putative candidate genes were identified in qRDR2.2 and qDR5.1/qTR5.2,respectively.These findings added to our knowledge of the genetic control of root traits in rice.In addition,this study will facilitate the future isolation of candidate genes of the deep-rooting trait and the utilization of Dongxiang wild rice in the improvement of rice drought resistance.
基金This work was supported by the National Natural Science Foundation of China(72271124,52232014,72071111,71801127,71671091).
文摘Survivability is used to evaluate the ability of the satellite to complete the mission after failure,while the duration of maintaining performance is often ignored.An effective backup strategy can restore the constellation performance timely,and maintain good network communication performance in case of satellite failure.From the perspective of network utility,the low Earth orbit(LEO)satellite constellation survivable graphical eva-luation and review technology(GERT)network with backup satel-lites is constructed.A network utility transfer function algorithm based on moment generating function and Mason formula is proposed,the network survivability evaluation models of on-orbit backup strategy and ground backup strategy are established.The survivable GERT model can deduce the expected mainte-nance time of LEO satellite constellation under different fault states and the network utility generated during the state mainte-nance period.The case analysis shows that the proposed surviv-able GERT model can consider the satellite failure rate,backup satellite replacement rate,maneuver control replacement ability and life requirement,and effectively determine the optimal sur-vivable backup strategy for LEO satellite constellation with limi-ted resources according to the expected network utility.
