Identification of new self-incompatibility alleles in sweet cherry (Prunusavium L.) and clarification of incompatibility groups by PCR and sequencing analysis

Correct assignment of sweet cherry cultivars to cross-compatibility groups is important for the efficient production of cherry fruit. Despite consider able confusion in the literature, these groups continue to be an effective tool for predicting pollination effectiveness for breeders and growers. PCR fragments generated from cherry S-RNase sequences coincided with specific S-allele phenotypes. Twenty five genomic DNA fragments, representing the si x most common alleles, were cloned and sequenced. In addition, fragments we re characterized from four new S-alleles. These genomic and cDNA sequences were invariant among cultivars with the same S-allele. Using the sequence d ata, PCR and restriction enzyme-based methodology was developed for rapid a nalysis of S-genotypes. Analysis and description of fragmentation patterns for S-allele determination are discussed. The method was utilized to charac terize the S-allele composition of 70 sweet cherry cultivars obtained from collections in North America, including many of the named releases from the Canadian breeding programs at Agriculture and A,ori-Food Canada in Summerl and, B.C., and Vineland, Ontario. A number of differences between published S-allele assignments and PCR data were discovered and a new listing of cul tivar S-allele assignments is presented.