Fig. 1.
Fig. 1.

Pedigree of DRH families used for self-fertility study. Inbred series of diploid potato generated from a cross between DM (female parent) and RH (male parent). Successive selfing starting with five F1 plants (16, 67, 76, 84, and 90) yielded increasingly inbred progenies. Families for which no seed was obtained from self-pollinations could not be advanced to the next generation. Each generation is designated on the left. Numbers in parentheses indicate the number of individual genotypes in each family. RH could only be selfed for a single generation because the S1 plants flowered poorly or not at all. The ⊗ symbol designates self-pollinations.

 


Fig. 2.
Fig. 2.

In vivo pollen tube germination. Fertile and nonfertile selections of the DRH F1 population were pollinated and styles and ovaries fixed and stained with aniline blue for observation of pollen germination 48 h later. (A) Left panel, stigma end of unpollinated fertile DRH line 171; right panel, ovary end of unpollinated style. (B) left panel, stigma end of self-incompatible diploid line DM 9-9 203/16 × N8-2 displaying tube starting to grow but arresting immediately beyond the stigma; right panel, ovary end of the self-incompatible control line displaying no tubes entering the ovary. (C) left panel, stigma end of fertile DRH line 171 displaying tubes traveling down the style; left panel, ovary end displaying tubes entering the ovary. (D) and (E) left panels, stigma end of nonfertile lines DRH 161 and DRH 001 displaying tubes traveling down the style; right panels, ovary end of style displaying pollen tubes entering ovary tissue.

 


Fig. 3.
Fig. 3.

Significant single-nucleotide polymorphisms (SNPs) for fruit set in DRH F1. (A) Level of significance of SNPs (p ≤ 0.0001) linked with fruit set in the F1 generation plotted according to physical position along chromosome 12. Plot generated using JMP Pro 10 (SAS Institute, 2012). (B) Ideogram designating physical location (Mb) on chromosome 12 of significant SNPs for fruit set in the F1 generation. Only one SNP per scaffold is represented (29 loci hidden). SNPs c2_5713, c2_5594, and c2_5524 were significant for both fruit set and seed set in the F1 generation. Positions along the chromosome are organized from top to bottom. Ideogram generated using MapChart 2.2 (Voorrips, 2002).

 


Fig. 4.
Fig. 4.

Ideograms of loci that retained more than 50% heterozygosity after three generations of inbreeding across three sibling DRH families. Numbers under images indicate linkage groups. (A) Common heterozygous loci (n = 46, black lines) to all three families. Loci (n = 137) marked with red lines on chromosomes 3, 4, 5, 6, 7, 8, and 9 were homozygous and fixed for the DM allele in all three populations. The single locus in red on chromosome 12 was fixed for an RH allele. (B) Heterozygous loci unique to DRH family 16 (n = 424), (C) family 76 (n = 304), and (D) family 90 (n = 134).