Abstract
Ear traits are key contributors to grain yield in maize; therefore, exploring their genetic basis facilitates the improvement of grain yield. However, the underlying molecular mechanisms of ear traits remain obscure in both inbred lines and hybrids. Here, two association panels, respectively, comprising 203 inbred lines (IP) and 246 F1 hybrids (HP) were employed to identify candidate genes for six ear traits. The IP showed higher phenotypic variation and lower phenotypic mean than the HP for all traits, except ear tip-barrenness length. By conducting a genome-wide association study (GWAS) across multiple environments, 101 and 228 significant single-nucleotide polymorphisms (SNPs) associated with six ear traits were identified in the IP and HP, respectively. Of these significant SNPs identified in the HP, most showed complete–incomplete dominance and over-dominance effects for each ear trait. Combining a gene co-expression network with GWAS results, 186 and 440 candidate genes were predicted in the IP and HP, respectively, including known ear development genes ids1 and sid1. Of these, nine candidate genes were detected in both populations and expressed in maize ear and spikelet tissues. Furthermore, two key shared genes (GRMZM2G143330 and GRMZM2G171139) in both populations were found to be significantly associated with ear traits in the maize Goodman diversity panel with high-density variations. These findings advance our knowledge of the genetic architecture of ear traits between inbred lines and hybrids and provide a valuable resource for the genetic improvement of ear traits in maize.
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Acknowledgements
We thank all members in the Key Laboratory of Biology and Genetic Improvement of Maize in Arid Area of Northwest Region for their help and support in field material planting and phenotype collection.
Funding
This work was supported by the Shanxi Province Research and Development Project (202102140601002) and Shaanxi Province Research and Development Project (2023-YBNY-027).
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JX and SX conceived and designed the experiments. XZ, YD, and ZF performed the experiments. HY, RL, NW, JZ, LZ, and XZ performed the experiments and collected and processed the data. TL analyzed the data, wrote the paper, and prepared figures and/or tables. All authors read and approved the final manuscript.
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Li, T., Yang, H., Zhang, X. et al. Genetic architecture of ear traits based on association mapping and co-expression networks in maize inbred lines and hybrids. Mol Breeding 43, 78 (2023). https://doi.org/10.1007/s11032-023-01426-9
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DOI: https://doi.org/10.1007/s11032-023-01426-9