title: Joint-linkage mapping and GWAS reveal extensive genetic loci that regulate male inflorescence size in maize.
abstract: Both insufficient and excessive male inflorescence size leads to a reduction in maize yield. Knowledge of the genetic architecture of male inflorescence is essential to achieve the optimum inflorescence size for maize breeding. In this study, we used approximately eight thousand inbreds, including both linkage populations and association populations, to dissect the genetic architecture of male inflorescence. The linkage populations include 25 families developed in the U.S. and 11 families developed in China. Each family contains approximately 200 recombinant inbred lines (RILs). The association populations include approximately 1000 diverse lines from the U.S. and China. All inbreds were genotyped by either sequencing or microarray. Inflorescence size was measured as the tassel primary branch number (TBN) and tassel length (TL). A total of 125 quantitative trait loci (QTLs) were identified (63 for TBN, 62 for TL) through linkage analyses. In addition, 965 quantitative trait nucleotides (QTNs) were identified through genomewide study (GWAS) at a bootstrap posterior probability (BPP) above a 5% threshold. These QTLs/QTNs include 24 known genes that were cloned using mutants, for example Ramosa3 (ra3), Thick tassel dwarf1 (td1), tasselseed2 (ts2), liguleless2 (lg2), ramosa1 (ra1), barren stalk1 (ba1), branch silkless1 (bd1) and tasselseed6 (ts6). The newly identified genes encode a zinc transporter (e.g. GRMZM5G838098 and GRMZM2G047762), the adapt in terminal region protein (e.g. GRMZM5G885628), O-methyl-transferase (e.g. GRMZM2G147491), helix-loop-helix (HLH) DNA-binding proteins (e.g. GRMZM2G414252 and GRMZM2G042895) and an SBP-box protein (e.g. GRMZM2G058588). These results provide extensive genetic information to dissect the genetic architecture of inflorescence size for the improvement of maize yield.
authors.affiliation: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.|Nanchong Academy of Agricultural Sciences, Nanchong, Sichuan, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Wu
authors.affiliation: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yunsu
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Song
authors.affiliation: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Dengfeng
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Li
authors.affiliation: Institute for Genomic Diversity, Cornell University, Ithaca, NY, USA.|USA Department of Agriculture-Agricultural Research Service, Ithaca, NY, USA.
authors.forename: Edward S
authors.initials: ES
authors.lastname: Buckler
authors.affiliation: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Agronomy, Northeast Agricultural University, Harbin, Heilongjiang, China.|Department of Crop and Soil Sciences, Washington State University, Pullman, WA, USA.
authors.forename: Zhiwu
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Tianyu
authors.initials: T
authors.lastname: Wang
mesh_terms: D002874:Chromosome Mapping; D035264:Flowers / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D017343:Genes, Plant; D055106:Genome-Wide Association Study; D005838:Genotype; D010641:Phenotype; D040641:Quantitative Trait Loci; D003313:Zea mays / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development
keywords: GWAS; QTLs; candidate gene; joint-linkage; maize; male inflorescence size