Identification of molecular markers linked to natural astringency loss of persimmon

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The pollination-constant and non-astringent (PCNA)-type fruit is the most desirable persimmon for fresh consumption, and new PCNA-type cultivars with good fruit quality have been awaited worldwide. However, the inheritance of PCNA-type is qualitative and the PCNA-type is recessive to non-PCNA (PVNA, PVA, and PCA) types. Molecular marker closely linked to the trait of natural astringency-loss is a powerful tool for the breeding project. So, we tried to establish it by the following experiments to make the breeding process more efficient.1. Bulked segregant analysis (BSA) of 6 PCNA-type and 10 non-PCNA-type offspring in breeding population was performed by AFLP method using 128 primer combinations. As a result, 4 potential AFLP markers were detected for discriminating PCNA- and non-PCNA types.2. The most reliable marker among 4 potential AFLP markers was selected and sequenced. When this marker was used as a probe for Southern analysis after genomic DNA was digested HindlII, all progenies examined could be distinguished between PCNA-type and non-PCNA type by the existence or absence of 6.5kb or 8.0 kb band. Furthermore, segregation rate of these bands indicated that persimmon shows polysomic inheritance. Persimmon seemed to be an auto- or autoallo-hexaploid.3. When Southern analysis using AFLP maker as a probe was examined to existing cultivars, PCNA cultivars could be distinguished from non-PCNA culitvars with 100% accuracy. This result indicates a high reliability of this analysis for selecting PCNA-type among wider breeding populations.4. The sequencing analysis of two RFLP markers (6.5 kb and 8.0 kb) for characterizing them and making primers for PCR analysis for easier detection of these makers was not completely successful. We could sequence 8.0 kb band but not 6.5 kb band. So, further study was needed to design PCR primers for more easier method than Southern analysis to distinguish PCNA-type from non-PCNA-type.