Theoretical expectation for population sizes required for detection of HF events at various expected HF frequencies.

<p>Sample sizes required were calculated for each expected HF frequency to ensure to detect HF events at probability levels of 0.90, 0.95 and 0.99, respectively.</p

Probability of a marker confirming a hetero-fertility event.

<p>*The number of markers that are expected to be polymorphic was estimated using the averaged polymorphism rate (36.3%) as revealed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0016101#pone.0016101-Yan1" target="_blank">[16]</a> using the same SNP chip for genotyping.</p

Detection of hetero-fertilization event contributed by maternal gametophyte in three-way cross populations.

<p>An HF plant in HP9 was detected as shown by the arrow. E: endosperm, L: leaf; A, B and C: three alleles derived from three different parents in the cross model (A×B)×C.</p

Hetero-fertilization frequencies detected in four three-way cross populations.

<p>Note: The two pollination models for three-way crosses are (A×B)×C and A×(B×C). For consistency, the genotypes of SSR allele combination in endosperm (E) and leaf (L) are shown using the same symbol with the pollination model A, B and C.</p

A diagram showing the probability for an HF event to be detected by using one polymorphic marker.

<p>For a given HF event and a given segregating marker locus within a population, two independent sperm cells derived from two different pollen grains, represented by H (triangle) and h (circle), respectively, can be only detected, with the probability of 50% (A), when the two pollen grains carry different alleles. However, when the two pollen grains carry the same allele (either H or h), the HF event is not detectable. The chance for the two pollen grains to carry the same H (B) or h (C) is 25%.</p

Hetero-fertilization event detected in F₂ populations.

<p>Genotype difference between endosperm DNA (E) and embryo DNA (L) can be revealed by one polymorphic SSR marker as shown by the arrow.</p

Detection of hetero-fertilization event contributed by different pollen grains in three-way cross populations.

<p>An HF plant in HP10 was detected as shown by the arrow. E: endosperm, L: leaf; A, B and C: three alleles derived from three different parents in the cross model (A×B)×C.</p

Hetero-fertilization frequencies as detected by one or two markers in seven F₂ populations.

<p>Note: The pollination model for five F₂ populations is A×B, where A is used as female parent and B as male parent. For consistency, the genotypes of SSR allele combination in endosperm (E) and leaf (L) are shown using the same symbol with the pollination model A and B.</p