ISHS Acta Horticulturae 800: X International Pear Symposium
SELECTION OF SELF-COMPATIBLE TREES BY S4sm-HAPLOTYPE SPECIFIC MARKER IN JAPANESE PEAR |
| Authors: | K. Okada, N. Tonaka, T. Takasaki, T. Matsumoto, Y. Sawamura |
| Keywords: | self-incompatibility, self-compatibility, DNA marker, S-RNase, S-genotype |
| Abstract:
An S4sm-haplotype derived from a self-compatible cultivar 'Osa Nijisseiki' (S2S4sm; sm = stylar-part mutant) is extensively used to breed self-compatible cultivars in Japanese pear. To aid the early selection of self-compatible trees from a cross-progeny, S-RNase based CAPS marker systems have been used, but yield no products from the S4sm-haplotype. We developed an S4sm-haplotype specific DNA marker based on the recent result that the S4sm-haplotype lacks approximately 236 kb around the S4-RNase. A primer pair ‘SM-F’ and 'SM-R' was designed from the deletion junction sequences in the S4sm-haplotype. Genomic PCR with ‘SM-F’ and ‘SM-R’ yielded a product of 666 bp from S4sm-haplotype but did not from S1- to S9-haplotypes. This indicates that the product of 666 bp can be used as a DNA marker specific for the S4sm-haplotype. Using the S4sm-haplotype specific marker and a CAPS marker system for discriminating S1- to S9-RNase alleles, a cross-progeny of 'Osa Nijisseiki' (S2S4sm) × ‘Nansui’ (S4S9) was genotyped. Based on the S-genotype, four S4smS9 trees were selected as self-compatible trees. These four selections were confirmed to be self-compatible by self-pollination tests. Therefore, the combination of the S4sm-haplotype specific marker and the CAPS marker system provides an early and reliable selection system of SC trees in Japanese pear and is useful for the breeding of self-compatible cultivars in Japanese pear using the S4sm-haplotype. | |
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