Figure 5.—

Alleles segregating in the F₂ populations and their frequency response during recurrent selection. The shaded bar represents a segment of chromosome 8. The locations of five linked SEL* SSR loci and previously mapped QTL (solid bars) and a major gene (HtN) are indicated. The centimorgan values shown for each marker were from the IBM2n genetic map. The C₄-derived haplotype segregating in each F₂ population is illustrated as described in the text. The allele-frequency plots show all of the alleles per locus (detected in the recurrent selection population) as dots but only the alleles segregating in the F₂ populations are labeled. The notation (e.g., f1 and f2 for two “favorable” alleles and n for “neutral” or drifting alleles) allows the alleles at each locus to be traced between the allele-frequency plots and F₂ populations. The B73 haplotype was common to each F₂ population. The level of significance determined using the log-rank statistic of survival analysis is indicated by asterisks (*P < 0.05; **P < 0.01; ***P < 0.001). The most significantly associated marker is indicated by white text in a black background (for POP3 the allele indicated was significant at P = 0.09). The “na” superscript indicates that the locus was not tested, either because no genotype data were collected (POP1) or because the locus was monomorphic. The allele-frequency plots for each locus constituting the haplotypes depict alleles as dots and the upper and lower bounds of the 95% confidence interval of genetic drift as shaded lines.