Figure 1.

Genetic dissection of a 55 Mb region on chromosome 7 identifies ZmAbh4 as modulating WUE and Δ¹³C in maize. A, Genomic composition of nine near-isogenic maize lines (NILs) and the recurrent parent (RP) in the region between 111 and 166 Mb on chromosome 7. Illustrated are homozygous introgressions from a donor parent in the genetic background of the recurrent parent. Dotted line marks the 200 kb region (129.798–129.995 Mb), where the genes ZmHsftf21 and ZmAbh4 are located. Breakpoint positions for all NILs are given in Supplemental Table S1. B, ZmAbh4 gene structure in RP and three NILs. The RP allele of the gene (blue) contains an 18 kb insertion in intron 4 (marked by a triangle), which is not present in the NIL B allele (green). The respective properties of the NILs compared to RP (two-sided Dunnett’s test) in terms of kernel carbon isotope discrimination (Δ¹³C_Kernel), whole plant WUE (WUE_plant), intrinsic water use efficiency (iWUE), stomatal conductance (g_s), and ABA leaf concentrations were assessed and P-values are presented as heatmaps (P < 0.05 in green). Means ± SD and n are presented in Supplemental Table S2.