Data from: Hybrid breakdown caused by epistasis-based recessive incompatibility in a cross of rice (Oryza sativa L.)

Viability and fertility in organisms depend on epistatic interactions
between loci maintained in lineages. Here, we describe reduced fitness of
segregants (hybrid breakdown, HB) that emerged in an F2 population derived
from a cross between 2 rice (Oryza sativa L.) cultivars, “Tachisugata”
(TS) and “Hokuriku 193” (H193), despite both parents and F1s showing
normal fitness. Quantitative trait locus (QTL) analyses detected 13 QTLs
for 4 morphological traits associated with the HB and 6 associated with
principal component scores calculated from values of the morphological
traits in the F2 population. Two-way analysis of variance of the putative
QTLs identified 4 QTL pairs showing significant epistasis; among them, a
pair on chromosomes 1 and 12 made the greatest contribution to HB. The
finding was supported by genetic experiments using F3 progeny. HB emerged
only when a plant was homozygous for the TS allele at the QTL on
chromosome 1 and homozygous for the H193 allele at the QTL on chromosome
12, indicating that each allele behaves as recessive to the other. Our
results support the idea that epistasis is an essential part of hybrid
fitness.