Seed abortion caused by the combination of two duplicate genes in the progeny from the cross between and .

Seed development is an essential phenomenon for all sexual propagative plant species. The functional allele at () or () loci is essential for seed development for and . In the present study, we performed fine mapping of , narrowing down the area of interest to 333kb on chromosome 6. Haplotype analysis around the locus of accessions indicated that they shared the DNA polymorphism, suggesting that they have a common abortive allele at the locus. Linkage analysis of the candidate gene showed that it was located on chromosome 4. The candidate was confirmed using a population in which both the and genes were segregating. The chromosomal region covering the gene was predicted to contain 30 protein-coding genes in . Five of these genes have conserved DNA sequences in the chromosomal region of the gene on chromosome 4, and not on chromosome 6, of . These results suggest that these five genes could be candidates for , and that their orthologous genes located on chromosome 4 of could be candidates for .