title: Hybrid breakdown caused by epistasis-based recessive incompatibility in a cross of rice (Oryza sativa L.).
abstract: 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.
authors.affiliation: From the NARO Institute of Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8518, Japan (Matsubara and Kato); and the National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan (Yamamoto, Mizobuchi, Yonemaru, Yamamoto, and Yano). Eiji Yamamoto is now at the NARO Institute of Vegetable and Tea Science, Tsu, Mie 514-2392, Japan. Masahiro Yano is now at the NARO Institute of Crop Science, Tsukuba, Ibaraki 305-8518, Japan. Hiroshi Kato is now at the National Institute of Agrobiological Sciences, Hitachiohmiya, Ibaraki 319-2293, Japan. vague@affrc.go.jp hkato@affrc.go.jp.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Matsubara
authors.affiliation: From the NARO Institute of Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8518, Japan (Matsubara and Kato); and the National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan (Yamamoto, Mizobuchi, Yonemaru, Yamamoto, and Yano). Eiji Yamamoto is now at the NARO Institute of Vegetable and Tea Science, Tsu, Mie 514-2392, Japan. Masahiro Yano is now at the NARO Institute of Crop Science, Tsukuba, Ibaraki 305-8518, Japan. Hiroshi Kato is now at the National Institute of Agrobiological Sciences, Hitachiohmiya, Ibaraki 319-2293, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Yamamoto
authors.affiliation: From the NARO Institute of Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8518, Japan (Matsubara and Kato); and the National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan (Yamamoto, Mizobuchi, Yonemaru, Yamamoto, and Yano). Eiji Yamamoto is now at the NARO Institute of Vegetable and Tea Science, Tsu, Mie 514-2392, Japan. Masahiro Yano is now at the NARO Institute of Crop Science, Tsukuba, Ibaraki 305-8518, Japan. Hiroshi Kato is now at the National Institute of Agrobiological Sciences, Hitachiohmiya, Ibaraki 319-2293, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Mizobuchi
authors.affiliation: From the NARO Institute of Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8518, Japan (Matsubara and Kato); and the National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan (Yamamoto, Mizobuchi, Yonemaru, Yamamoto, and Yano). Eiji Yamamoto is now at the NARO Institute of Vegetable and Tea Science, Tsu, Mie 514-2392, Japan. Masahiro Yano is now at the NARO Institute of Crop Science, Tsukuba, Ibaraki 305-8518, Japan. Hiroshi Kato is now at the National Institute of Agrobiological Sciences, Hitachiohmiya, Ibaraki 319-2293, Japan.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Yonemaru
authors.affiliation: From the NARO Institute of Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8518, Japan (Matsubara and Kato); and the National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan (Yamamoto, Mizobuchi, Yonemaru, Yamamoto, and Yano). Eiji Yamamoto is now at the NARO Institute of Vegetable and Tea Science, Tsu, Mie 514-2392, Japan. Masahiro Yano is now at the NARO Institute of Crop Science, Tsukuba, Ibaraki 305-8518, Japan. Hiroshi Kato is now at the National Institute of Agrobiological Sciences, Hitachiohmiya, Ibaraki 319-2293, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: From the NARO Institute of Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8518, Japan (Matsubara and Kato); and the National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan (Yamamoto, Mizobuchi, Yonemaru, Yamamoto, and Yano). Eiji Yamamoto is now at the NARO Institute of Vegetable and Tea Science, Tsu, Mie 514-2392, Japan. Masahiro Yano is now at the NARO Institute of Crop Science, Tsukuba, Ibaraki 305-8518, Japan. Hiroshi Kato is now at the National Institute of Agrobiological Sciences, Hitachiohmiya, Ibaraki 319-2293, Japan. vague@affrc.go.jp hkato@affrc.go.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kato
authors.affiliation: From the NARO Institute of Crop Science, 2-1-18 Kannondai, Tsukuba, Ibaraki 305-8518, Japan (Matsubara and Kato); and the National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan (Yamamoto, Mizobuchi, Yonemaru, Yamamoto, and Yano). Eiji Yamamoto is now at the NARO Institute of Vegetable and Tea Science, Tsu, Mie 514-2392, Japan. Masahiro Yano is now at the NARO Institute of Crop Science, Tsukuba, Ibaraki 305-8518, Japan. Hiroshi Kato is now at the National Institute of Agrobiological Sciences, Hitachiohmiya, Ibaraki 319-2293, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yano
mesh_terms: D000704:Analysis of Variance; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D004843:Epistasis, Genetic / Q000235:genetics*; D056084:Genetic Fitness / Q000235:genetics*; D005828:Genetics, Population; D005838:Genotype; D006824:Hybridization, Genetic; D012275:Oryza / Q000033:anatomy & histology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D025341:Principal Component Analysis; D040641:Quantitative Trait Loci
keywords: QTL analysis; SNP marker; epistasis; hybrid breakdown; rice