Different expression of S-locus cysteine-rich protein (SCR) alleles in self-incompatible and self-compatible Brassica napus breeding lines and cultivars: Can be SCR/SP11 used as a selectable marker in breeding?

Abstract

There are several approaches available for hybrid breeding in oil seed rape, Brassica napus, as cytoplasmic male sterility (CMS), genic male sterility (GMS), self-incompatibility (SI), and chemical hybridizing agens (CHA). In comparison with others, SI is regarded as one of the most valuable strategies in hybrid breeding. Unlike self-incompatible (SI) B. rapa and B. oleracea, two ancestor species, B. napus is naturally self-compatible (SC). However, occasionally SI also occurs in rapeseed cultivars. SI in Brassicaceae plants is sporophytically controlled by a single multi-allelic locus (S-locus), which contains at least three highly polymorphic genes expressed in the stigma (S locus glycoprotein, SLG and S receptor kinase, SRK) and in the pollen (SCR/SP11). In segregating population derived from crosses between DH SI lines and 00-quality donors we found two recessive alleles of a SCR class II gene. We developed new primers for detection of unique cv. Tandem derived allele and this allele was successfully amplified in SI donor plants and SI plants after first cycle of crossing. Analyses of other accessions (SI donor different from cv. Tandem) and varieties did not show so clear pattern of segregation and different expression of both alleles does not correspond to phenotypic manifestation of self-incompatibility and we can assume that it is caused by the presence of repressor gene that does not lie on the S-locus. Key words: Self-incompatibility, Brassica napus, S receptor kinase (SRK), S locus glycoprotein (SLG), S locus cysteine-rich protein (SCR).