Abstract
A nucleotide sequence of a new self-incompatible allele was identified in Japanese pear cultivars 'Shinsei' and 'Shinkou', designated as 'S9'. The obtained sequence was successfully translated into 167 deduced amino acids, in which both regions of 2 histidine residues, essential for RNase activity, and 6 cysteine residues having characteristics of S-RNase in Japanese pears, were conserved. An intron of about 1.1kbp was found within the S9 gene that was significantly homologous to the registered S genes from the pear and apple. The S9 was clustered with the S3 gene of apple on a dendrogram to suggest that they are closely related. Segregation analysis on the F1 progenies of 'Shinsei' x '282-12' indicated that the S9 was an allele on S locus and, hence, could act as S-RNase.
