Expression analysis of ZmGW2-CHR4 and ZmGW2-CHR5. A. Tissue expression patterns. 14e, 18e, ears from plants with 14 and 18 expanded leaves, respectively. DAP, days after pollination. The height of each column represents the relative expression level of the corresponding gene. B. Correlation between the expression levels of ZmGW2-CHR4 and kernel width. Kernels collected at 0 DAP were used for expression analysis.