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Theor Appl Genet. 2018 Mar;131(3):539-553. doi: 10.1007/s00122-017-3017-y. Epub 2017 Nov 17.

A novel allele of TaGW2-A1 is located in a finely mapped QTL that increases grain weight but decreases grain number in wheat (Triticum aestivum L.).

Zhai H1,2, Feng Z1,2, Du X3, Song Y1,2, Liu X1,2, Qi Z1,2, Song L1,2, Li J1,2, Li L1,2, Peng H1,2, Hu Z1,2, Yao Y1,2, Xin M1,2, Xiao S4, Sun Q1,2, Ni Z5,6.

Author information

1
State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China.
2
National Plant Gene Research Centre, Beijing, 100193, China.
3
Millet Research Institute, Shanxi Academy of Agricultural Sciences, Changzhi, 046011, Shanxi, China.
4
Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
5
State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China. nizf@cau.edu.cn.
6
National Plant Gene Research Centre, Beijing, 100193, China. nizf@cau.edu.cn.

Abstract

A novel TaGW2-A1 allele was identified from a stable, robust QTL region, which is pleiotropic for thousand grain weight, grain number per spike, and grain morphometric parameters in wheat. Thousand grain weight (TGW) and grain number per spike (GNS) are two crucial determinants of wheat spike yield, and genetic dissection of their relationships can help to fine-tune these two components and maximize grain yield. By evaluating 191 recombinant inbred lines in 11 field trials, we identified five genomic regions on chromosomes 1B, 3A, 3B, 5B, or 7A that solely influenced either TGW or GNS, and a further region on chromosome 6A that concurrently affected TGW and GNS. The QTL of interest on chromosome 6A, which was flanked by wsnp_BE490604A_Ta_2_1 and wsnp_RFL_Contig1340_448996 and designated as QTgw/Gns.cau-6A, was finely mapped to a genetic interval shorter than 0.538 cM using near isogenic lines (NILs). The elite NILs of QTgw/Gns.cau-6A increased TGW by 8.33%, but decreased GNS by 3.05% in six field trials. Grain Weight 2 (TaGW2-A1), a well-characterized gene that negatively regulates TGW and grain width in wheat, was located within the finely mapped interval of QTgw/Gns.cau-6A. A novel and rare TaGW2-A1 allele with a 114-bp deletion in the 5' flanking region was identified in the parent with higher TGW, and it reduced TaGW2-A1 promoter activity and expression. In conclusion, these results expand our knowledge of the genetic and molecular basis of TGW-GNS trade-offs in wheat. The QTLs and the novel TaGW2-A1 allele are likely useful for the development of cultivars with higher TGW and/or higher GNS.

PMID:
29150697
PMCID:
PMC5814529
DOI:
10.1007/s00122-017-3017-y
[Indexed for MEDLINE]
Free PMC Article

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