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Quantitative variation in maize kernel row number is controlled by the FASCIATED EAR2 locus

Abstract

Domestication of cereal crops, such as maize, wheat and rice, had a profound influence on agriculture and the establishment of human civilizations. One major improvement was an increase in seed number per inflorescence, which enhanced yield and simplified harvesting and storage1,2. The ancestor of maize, teosinte, makes 2 rows of kernels, and modern varieties make 8–20 rows3. Kernel rows are initiated by the inflorescence shoot meristem, and shoot meristem size is controlled by a feedback loop involving the CLAVATA signaling proteins and the WUSCHEL transcription factor4,5. We present a hypothesis that variation in inflorescence meristem size affects kernel row number (KRN), with the potential to increase yield. We also show that variation in the CLAVATA receptor–like protein FASCIATED EAR2 leads to increased inflorescence meristem size and KRN. These findings indicate that modulation of fundamental stem cell proliferation control pathways has the potential to enhance crop yields.

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Figure 1: Variation in maize ear inflorescence meristem size and KRN.
Figure 2: Isolation of weak alleles of FEA2 by TILLING.
Figure 3: Quantitative variation in FEA2 leads to enhanced KRN.

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Acknowledgements

We wish to thank C. Weil and the Maize TILLING facility for the isolation of the fea2 TILLING alleles, F. Taguchi Shiobara for SEM images, U. Au, L.A. Haller and K. Lau for KRN counting, P. Yin and K. Chen for assistance with genotyping, M. Bohn and S. Goldshmidt for assistance with statistical analysis, members of the Jackson laboratory for comments on the manuscript, T. Rocheford for growing IBM recombinant inbred lines, M. Komatsu, L. Heetland, K. Simcox and H. Sakai (DuPont- Pioneer) for grow-outs of TILLING populations and yield trait measurements, P. Brown and E. Buckler for discussions and A. Eveland for informatics. Funding from the US Department of Agriculture (USDA; grant NRICGP 2003-35304-13277), the National Science Foundation (NSF) Plant Genome Program (grant DBI-0604923) and the German Science Society (DFG) for a postdoctoral fellowship (grant Bo 3012/1-1) to P.B. is gratefully acknowledged.

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Contributions

P.B. performed all experiments, except where noted below, analyzed the data and helped with writing the manuscript. N.S.N. generated the data on the variation in maize inflorescence meristem size in different inbred lines. D.J. assisted with data analysis and wrote the manuscript.

Corresponding author

Correspondence to David Jackson.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Text and Figures

Supplementary Tables 1–3 and 5 (PDF 289 kb)

Supplementary Table 4

Genes and gene density in the FEA2 QTL interval. See separate file: FEA2_interval_gene annotations.xls (XLS 60 kb)

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Bommert, P., Nagasawa, N. & Jackson, D. Quantitative variation in maize kernel row number is controlled by the FASCIATED EAR2 locus. Nat Genet 45, 334–337 (2013). https://doi.org/10.1038/ng.2534

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