By reviewing the fertility transition in China,this paper discusses multiple drivers of fertility decline in the 1970s and 1990s,including the role of family planning policies at different stages of the transition.The...By reviewing the fertility transition in China,this paper discusses multiple drivers of fertility decline in the 1970s and 1990s,including the role of family planning policies at different stages of the transition.The improved status of women played a key role in the fertility transition of the 20th century,but work-family conflict and traditional gender roles have increased the cost of childbearing for women.These factors have contributed to both low fertility and postponement of childbearing in the 21st century.By learning from past experiences and understanding the more complex causes of low fertility today,response strategies should aim to benefit different groups across all stages of the life cycle and in all aspects of life.展开更多
Thermosensitive genic male sterility(TGMS)has been widely used in two-line hybrid rice breeding.Due to hybrid seed production being highly affected by changeable environments,its application scope is limited to some e...Thermosensitive genic male sterility(TGMS)has been widely used in two-line hybrid rice breeding.Due to hybrid seed production being highly affected by changeable environments,its application scope is limited to some extent.Thus,it is of great importance to identify potential TGMS genes in specific rice varieties.Here,Diannong S-1 xuan(DNS-1 X),a reverse TGMS(RTGMS)japonica male sterile line,was identified from Diannong S-1.Genetic analysis showed that male sterility was tightly controlled by a single recessive gene,which was supported by the phenotype of the F;and F;populations derived from the cross between DNS-1 X and Yunjing 26(YJ26).Combining simple sequence repeat(SSR)markers and bulked segregation analysis(BSA),we identified a 215 kb region on chromosome 10 as a candidate reverse TGMS region,which was designated as rtmsl-D.It was narrower than the previously reported RTGMS genes rtmsl and tms6(t).The fertility conversion detected in the natural environment showed that DNS-1 X was sterile below 28-30℃;otherwise,it was fertile.Histological analysis further indicated that the pollen abortion was occurred in the young microspore stage.This study will provide new resources for two-line hybrid rice and pave the way for molecular breeding of RTGMS lines.展开更多
文摘By reviewing the fertility transition in China,this paper discusses multiple drivers of fertility decline in the 1970s and 1990s,including the role of family planning policies at different stages of the transition.The improved status of women played a key role in the fertility transition of the 20th century,but work-family conflict and traditional gender roles have increased the cost of childbearing for women.These factors have contributed to both low fertility and postponement of childbearing in the 21st century.By learning from past experiences and understanding the more complex causes of low fertility today,response strategies should aim to benefit different groups across all stages of the life cycle and in all aspects of life.
基金financially Science and technology projects of Yunnan Province,China(Grant No.202003AD150007)Strategic Leading Science and Technology Programme of Chinese Academy of Sciences(Grant Nos.XDA24030301 and XDA24040308)+1 种基金Natural Science Foundation of Yunnan,China(Grant No.2018FA 023)National Natural Science Foundation of China(Grant No.31902110)。
文摘Thermosensitive genic male sterility(TGMS)has been widely used in two-line hybrid rice breeding.Due to hybrid seed production being highly affected by changeable environments,its application scope is limited to some extent.Thus,it is of great importance to identify potential TGMS genes in specific rice varieties.Here,Diannong S-1 xuan(DNS-1 X),a reverse TGMS(RTGMS)japonica male sterile line,was identified from Diannong S-1.Genetic analysis showed that male sterility was tightly controlled by a single recessive gene,which was supported by the phenotype of the F;and F;populations derived from the cross between DNS-1 X and Yunjing 26(YJ26).Combining simple sequence repeat(SSR)markers and bulked segregation analysis(BSA),we identified a 215 kb region on chromosome 10 as a candidate reverse TGMS region,which was designated as rtmsl-D.It was narrower than the previously reported RTGMS genes rtmsl and tms6(t).The fertility conversion detected in the natural environment showed that DNS-1 X was sterile below 28-30℃;otherwise,it was fertile.Histological analysis further indicated that the pollen abortion was occurred in the young microspore stage.This study will provide new resources for two-line hybrid rice and pave the way for molecular breeding of RTGMS lines.
