Background Microspore embryogenesis and cytoplasmic male sterility system (CMS) are two approaches widely exploited in Brassica napus breeding for production of homozygous doubled haploid (DH) lines and F1 hybrids respectively. Cytoplasmic male sterility system (CMS) is one of the most important pollination systems for hybrid seed production and utilisation of doubled haploid system to quickly prepare fully homozygous fertility restorer lines for CMS Ogu-INRA is very beneficial. Generally, only a small part of microspore-derived embryos is used for plant regeneration, without any knowledge about their properties. Therefore, the possibility of early detection of desirable genotypes bearing a single dominant nuclear fertility restorer (Rfo) gene, can double the success of selection and reduce the production costs. Results To maximize the efficiency and yield of regenerated microspore-derived embryos (MDEs) with the Rfo gene, a protocol for reliable and early, non-destructive selection of desired MDE genotypes was developed. The total amount of 636 cotyledonary embryos was tested by PCR, out of which 37% (237/636) were shown to bear the Rfo gene (instead of 50% according to the expected 1:1 segregation ratio for a single copy gene) and 218 of these fertility restorer plants were fully grown to flowering stage. New molecular marker has been demonstrated to have 100% of co-segregation with the phenotypic evaluation. Conclusion Technique developed in this study provides early and non-destructive sampling of embryonic tissue and the use of new markers for simple and efficient control of the presence of Rfo gene in all accessions.

The selection of desirable genotypes with recessive characteristics, such as self-incompatible plants, is often difficult or even impossible and represents a crucial barrier in accelerating the breeding process. Molecular approaches and selection based on molecular markers can allow breeders to overcome this limitation. The use of self-incompatibility is an alternative in hybrid breeding of oilseed rape. Unfortunately, stable self-incompatibility is recessive and phenotype-based selection is very difficult and time-consuming. The development of reliable molecular markers for detecting desirable plants with functional self-incompatible genes is of great importance for breeders and allows selection at early stages of plant growth. Because most of these reliable molecular markers are based on discrimination of class I S-locus genes that are present in self-compatible plants, there is a need to use an internal control in order to detect possible PCR inhibition that gives false results during genotyping. In this study, 269 double haploid F2 oilseed rape plants obtained by microspore embryogenesis were used to verify the applicability of an improved PCR assay based on the detection of the class I SLG gene along with an internal control. Comparative analysis of the PCR genotyping results vs. S phenotype analysis confirmed the applicability of this molecular approach in hybrid breeding programs. This approach allows accurate detection of self-incompatible plants via a different amplification profile.