Heading date(flowering time)determines the adaptability of cultivars to different environments.We report the fine mapping and candidate gene analysis of qHD1b,a quantitative trait locus(QTL)responsible for early flowering that was derived from common wild rice(O.rufipogon)under both short-day and long-day conditions.The introgression line IL7391,which carried segments from common wild rice in a Zhonghui 8015(ZH8015)background,exhibited early heading compared to the background and was crossed with ZH8015 to generate BC5F2:3 families for QTL analysis.This enabled the identification of two heading-date QTL,named qHD1b and qHD7,of which the first was selected for further research.High-resolution linkage analysis was performed in BC5F4:5 and BC5F6 populations,and the location of qHD1b was confined to a 112.7-kb interval containing 17 predicted genes.Five of these genes contained polymorphisms in the promoter or coding regions and were thus considered as candidates.Expression analysis revealed a positive association between LOC_Os01g11940 expression and early heading.This locus was annotated as OsFTL1,which encodes an ortholog of Arabidopsis Flowering Locus T and was the most likely candidate gene for qHD1b.Our study revealed that qHD1b acts as a floral activator that promotes flowering by up-regulating Ehd1,Hd3a,RFT1,OsMADS14,and OsMADS15 under both short-day and long-day conditions.Field experiments showed that qHD1b affected several yield-related agro-nomic traits including 1000-grain weight and grain length.qHD1b could be useful for marker-assisted selection and breeding of early-maturing cultivars.

Ling Liu;Yingxin Zhang;Zhengfu Yang;Qinqin Yang;Yue Zhang;Peng Xu;Jiaxin Li;Anowerul Islam;Liaqat Shah;Xiaodeng Zhan;Liyong Cao;Shihua Cheng;Weixun Wu

China National Center for Rice Improvement and State Key Laboratory of Rice Biology,China National Rice Research Institute,Hangzhou 310006,Zhejiang,China;State Key Laboratory of Subtropical Silviculture,Zhejiang A&F University,Hangzhou 311300,Zhejiang,China;Northern Center of China National Rice Research Institute,Hangzhou 310006,Zhejiang,China

作物学报（英文版）

[1]Ling Liu;Yingxin Zhang;Zhengfu Yang;Qinqin Yang;Yue Zhang;Peng Xu;Jiaxin Li;Anowerul Islam;Liaqat Shah;Xiaodeng Zhan;Liyong Cao;Shihua Cheng;Weixun Wu-.Fine mapping and candidate gene analysis of qHD1b,a QTL that promotes flowering in common wild rice(Oryza rufipogon)by up-regulating Ehd1)[J].作物学报（英文版）,2022(04):1083-1093

qHD1b,IL7391,ZH8015,BC5F2,qHD7,BC5F4,BC5F6,Os01g11940,OsFTL1,OsMADS14,OsMADS15

Fine,mapping,analysis,QTL,that,promotes,flowering,common,wild,rice,Oryza,rufipogon,by,up,regulating,Ehd1,Heading,determines,adaptability,cultivars,different,environments,We,report,quantitative,locus,responsible,early,was,derived,from,under,both,short,day,long,conditions,introgression,line,which,carried,segments,Zhonghui,background,exhibited,heading,compared,crossed,generate,families,This,enabled,identification,two,named,first,selected,further,research,High,resolution,linkage,performed,populations,location,confined,kb,interval,containing,predicted,genes,Five,these,contained,polymorphisms,promoter,coding,regions,were,thus,considered,candidates,Expression,revealed,positive,association,between,LOC,expression,annotated,encodes,ortholog,Arabidopsis,Flowering,Locus,most,likely,Our,study,acts,floral,activator,Hd3a,RFT1,Field,experiments,showed,affected,several,yield,related,agro,nomic,traits,including,grain,weight,length,could,useful,marker,assisted,selection,breeding,maturing

0.507336