Deploying QTL-seq rapid identification and separation of the major QTLs of tassel branch number for fine-mapping in advanced maize populations

Jixing Ni; Chong You; Zhengjie Chen; Dengguo Tang; Haimei Wu; Wujiao Deng; Xueying Wang; Jinchang Yang; Ruifan Bao; Zhiqin Liu; Pengxu Meng; Tingzhao Rong; Jian Liu

doi:10.1007/s11032-023-01431-y

Deploying QTL-seq rapid identification and separation of the major QTLs of tassel branch number for fine-mapping in advanced maize populations

Mol Breed. 2023 Nov 29;43(12):88. doi: 10.1007/s11032-023-01431-y. eCollection 2023 Dec.

Authors

Jixing Ni^#¹, Chong You^#¹, Zhengjie Chen², Dengguo Tang¹, Haimei Wu¹, Wujiao Deng¹, Xueying Wang¹, Jinchang Yang¹, Ruifan Bao¹, Zhiqin Liu¹, Pengxu Meng¹, Tingzhao Rong¹, Jian Liu¹

Affiliations

¹ Maize Research Institute, Sichuan Agricultural University, No. 211 Huiming Road, Wenjiang District, Chengdu, 611130 Sichuan China.
² Sichuan Advanced Agricultural & Industrial Institute, China Agriculture University, No.8 Xingyuan Road, Xinjin District, Chengdu, 611430 Sichuan China.

^# Contributed equally.

PMID: 38045561
PMCID: PMC10686902 (available on 2024-11-29)
DOI: 10.1007/s11032-023-01431-y

Abstract

The tassel competes with the ear for nutrients and shields the upper leaves, thereby reducing the yield of grain. The tassel branch number (TBN) is a pivotal determinant of tassel size, wherein the reduced TBN has the potential to enhance the transmission of light and reduce the consumption of nutrients, which should ultimately result in increased yield. Consequently, the TBN has emerged as a vital target trait in contemporary breeding programs that focus on compact maize varieties. In this study, QTL-seq technology and advanced population mapping were used to rapidly identify and dissect the major effects of the TBN on QTL. Advanced mapping populations (BC₄F₂ and BC₄F₃) were derived from the inbred lines 18-599 (8-11 TBN) and 3237 (0-1 TBN) through phenotypic recurrent selection. First, 13 genomic regions associated with the TBN were detected using quantitative trait locus (QTL)-seq and were located on chromosomes 2 and 5. Subsequently, validated loci within these regions were identified by QTL-seq. Three QTLs for TBN were identified in the BC₄F₂ populations by traditional QTL mapping, with each QTL explaining the phenotypic variation of 6.13-18.17%. In addition, for the major QTL (qTBN2-2 and qTBN5-1), residual heterozygous lines (RHLs) were developed from the BC₄F₂ population. These two major QTLs were verified in the RHLs by QTL mapping, with the phenotypic variation explained (PVE) of 21.57% and 30.75%, respectively. Near-isogenic lines (NILs) of qTBN2-2 and qTBN5-1 were constructed. There were significant differences between the NILs in TBN. These results will enhance our understanding of the genetic basis of TBN and provide a solid foundation for the fine-mapping of TBN.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-023-01431-y.

Keywords: BC4F2 population; Maize; Major QTL; Near-isogenic lines; QTL-seq; Tassel branch number.

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