| Yield was the most important tairt, which was the main objective in breeding. And analysis directly on yield is a hard work because yield belongs to quantitative character.The development of molecular marker technology facilitated genetic mapping of genes and QTLs, also provided an important tool to comparative mapping of different species at the DNA level. QTL localizations and genomic sequence analysis of grass species with rice as model plant generate a great capacity of data. In this study, QTL about yield components in maize genomic database were explored, and the consensus map was constructed using high-density linkage map IBM2 neighbors 2005 and the adjacent markers to each QTL; The"consensus"QTL was found by a meta-analysis method; The gene and marker sequences within"consensus"QTL were downloaded respectively from website Maize GDB, and candidate genes were identified by comparing these sequences against genes of other Poacease by internet software BLASTx; Rice and maize yield components genes were projected onto maize genetic map IBM2 2005 Neighbors, and found candidate genes in"consensus QTL"using a synteny conservation approach based on comparative mapping between maize genetic map and rice physical map. The results are as follows:1,A total of 411 QTL relevanted to 10 yield components were found in MaizeGDB and GRAMENE from 1992 year as yet. These QTLs were located on 22 maize genetic maps, which were Maize-NCSU Ac7729/Ac7643S QTL 1992, Maize-Iowa Mo17/H99 RI QTL 1998, Pioneer composite 1999, and et al.2,The integration QTL map for yield in maize was constructed by BioMercator 2.1 software by compiling a total of 221 QTL available for this trait with Genetic Map IBM2 2005 neighbors as reference. These 221 QTL were found to be located on all of maize 10 chromosomes. 61QTLs relevant to grain yield and 99 QTLs relevant to kernel weight were located on all of maize 10 chromosomes; 30 QTLs relevant to ear number were located on 9 chromosomes of maize except for chromosome 10; 18 QTLs relevant to kernel row number were located on 9 chromosomes of maize except for chromosome 8; 13 QTLs relevant to kernel number were located respectively on 1, 3, 4, 7, 8, 10 chromosomes. In the integration QTL map, there were many QTL clustering of grain yield and its components in Maize. 3,Using a meta-analysis method, 3"consensus"QTL relevant to kernel weight and ear number were identified on chromosomes 2, 3 and 4, which was positioned between the markers Sdg107 and Isu2117b, ucsd72d and IDP3796, ufg23 and IDP3796, with map interval of 30.99cM, 12.64cM and 69.72cM, respectively; 2"consensus"QTL relevant to kernel weight, grian yield and ear number were identified on chromosomes 6 and 9, which was positioned between the markers bnlg1732 and bnl8.08c, TB-9Sb(9) and gpm682, with map interval of 14.51cM and 40.8cM, respectively.4,The study was identified 7 candidate genes on the"consensus QTL"of chromosomes 2, 3 and 6 by comparing these sequences with other genes by software BLASTx in NCBI website.2 candidate genes were on chromosome 2, which were AY106958 sequence of marker pco100533a and AY106749 sequence of marker pco120693, with conserved domains of S_TKc and PRK02304, respectively. 2 candidate genes were on chromosome 3, which were L46398 sequence of marker ucsd72d and AY106058 sequence of marker pco147797a, with conserved domains of MADS_MEF2_like and Aldo_ket_red, respectively. 3 candidate genes were on chromosome 6, which were AY103731 sequence of marker pco061870a, X59714 sequence of marker six59714d and AY105226 sequence of marker pco110390, with conserved domains of TatD_DNAse, CBFD_NFYB_HMF and FKBP_C, respectively.5,A total of 53 rice and maize yield genes were projected onto maize genetic map IBM2 2005 Neighbors by mapchart software, using a synteny conservation approach based on comparative mapping between maize genetic map and rice physical map .2 genes relevanted rice yield was found in 2"consensus QTL". Rgene-7 involving in the expression of rice tilling was found in the"consensus QTL"of chromosome 2 with the Coordinate was 236.4 and Rgene-24 involving in the expression of rice tilling was found in the"consensus QTL"of chromosome 6 with the Coordinate was 387.2, which was determined as the positional candidate gene of the grain yield in maize. |
