DOES THE GENOME OF CORYLUS-AVELLANA L CONTAIN SEQUENCES HOMOLOGOUS TOTHE SELF-INCOMPATIBILITY GENE OF BRASSICA

Self-incompatibility is a genetic mechanism enforcing cross-pollinatio n in plants. Hazelnut (Corylus avellana L.) expresses the sporophytic type of self-incompatibility, for which the molecular genetic basis is characterized only in Brassica. The hypothesis that the hazelnut geno me contains homologs of Brassica self-incompatibility genes was tested . The S-locus glycoprotein gene (SLG) and the kinase-encoding domain o f the S-receptor kinase (SRK) gene of B. oleracea L. were used to prob e blots of genomic DNA from six genotypes of hazelnut. Weak hybridizat ion with the SLG probe was detected for all hazelnut genotypes tested; however, no-hybridization was detected with PCR-generated probes corr esponding to two conserved regions of the SLG gene. One of these PCR p robes included the region of SLG encoding the 11 invariant cysteine re sidues that are an important structural feature of all S-family genes. The present evidence suggests that hazelnut DNA hybridizing to SLG di ffers significantly from the Brassica gene, and that the S-genes clone d from Brassica will not be useful for exploring self-incompatibility in hazelnut.