Interspecific crossing of the African indigenous @entity579 Oryza glaberrima with @entity579 cultivars is hindered by crossing barriers causing 100% @entity249 in F(1) hybrids. Since hybrids are partially female fertile, fertility can be restored by back crossing (BC) to a recurrent male parent. Distinct genetic models on @entity249 have been developed predicting, e.g., the existence of a gamete eliminator and/or a pollen killer. Linkage of sterility to the waxy starch synthase gene and the chromogen gene C, both located on chromosome 6, have been demonstrated. We selected a segregating BC(2)F(3) population of semi-sterile O. glaberrima x @entity5556 hybrid progenies for analyses with PCR markers located at the respective chromosome-6 region. These analyses revealed that semi-sterile plants were heterozygous for a marker (OSR25) located in the waxy promoter, whereas fertile progenies were homozygous for the O. glaberrima allele. Adjacent markers showed no linkage to @entity249 . @entity249 of hybrid progenies was maintained at least until the F(4) progeny generation, suggesting the existence of a pollen killer in this plant material. Monitoring of reproductive plant development showed that @entity249 was at least partially due to an arrest of pollen development at the microspore stage. In order to address the question whether genes responsible for F(1) sterility in intraspecific hybrids ( @entity5556 x japonica) also cause @entity249 in interspecific hybrids, crossings with wide compatibility varieties (WCV) were performed. WCV accessions possess "neutral" S-loci ( S(n)) improving fertility in intraspecific hybrids. This experiment showed that the tested S(n)-loci had no fertility restoring effect in F(1) interspecific hybrids. Pollen development was completely arrested at the microspore stage and grains were never obtained after selfing. This suggests that distinct or additional S-loci are responsible for sterility of O. glaberrima x @entity579 hybrids.

Assessing hybrid sterility in Oryza glaberrima x XXXX hybrid progenies by PCR marker analysis and crossing with wide compatibility varieties.

@entity249 :: ('MESH:D007246', 'Disease') :: ['Semi-sterility', 'spikelet sterility'] @entity579 :: ('4530', 'Species') :: ['O. sativa', 'Oryza sativa', 'rice'] @entity5556 :: ('39946', 'Species') :: ['O. sativa indica']
@entity579 :: (4530,Species) :: ['O. sativa']
