A, LOD profiling using the single QTL model. Locations of genotyping SNPs are shown as ticks on the abscissa. 95% confidence level (dashed line) was estimated using 1000 permutations. Inset, higher resolution genetic map of the peak on chromosome 7. The location of the marker nearest the peak is indicated (triangle). B, LOD profiling using the multiple QTL model. Significant QTLs were found on chromosomes 1, 3, 7, and 8 for number (black line), on chromosome 7 for diameter (dashed line), and on chromosomes 1 and 7 for conductance (dot-dash line). Inset, schematic of the multiple QTL model for collateral number having the highest LOD. The solid line denotes interaction between the QTLs on chromosomes 1 and 3 (LOD score 7).