Development of molecular markers linked to the allele associated with the non-astringent trait of the Chinese persimmon (Diospyros kaki Thunb.)

Persimmon cultivars are classified into four types depending on the nature of astringency loss of the fruit, namely pollination constant non-astringent (PCNA), pollination variant non-astringent (PVNA), pollination variant astringent (PVA), and pollination constant astringent (PCA). Among these four types, PCNA is the most important cultivar for persimmon breeding due to the stable loss of natural astringency on the tree. The trait of natural astringency loss is recessive in Japanese PCNA cultivars, while that in the Chinese PCNA cultivar, 'Luo tian tian shi', is dominant and the latter locus, termed CPCNA, is different from that in Japanese cultivars. In order to develop a molecular marker for the selection of the CPCNA-type cultivar, we performed amplified fragment length polymorphism (AFLP) in combination with bulked segregant analysis for F₁offspring derived from 'Luo tian tian shi', which was used as the maternal parent. A total of 384 primer combinations were tested, and three AFLP markers, namely EACT-MCCC-222 (RO1), EGGC-MCTC-309 (RO2), and EGCC-MCGA-105 (RO3), linked to the CPCNA dominant allele were obtained. Among these markers, EGGC/MCTC-309 (RO2) was converted into a sequence-characterized amplified region (SCAR) marker. PCR analysis using F₁offspring (n = 264) revealed that the relevance ratio of the SCAR marker was 94%. The polymorphism of the RO2 marker, which was strongly linked to the CPCNA dominant allele, was detected in only two Chinese PCNA cultivars, namely 'Luo tian tian shi' and 'Tian bao gai', among the Chinese, Korean, and Japanese cultivars tested. These results indicate that the RO2 marker contributes to marker-assisted selection for breeding programs of new PCNA cultivars having the CPCNA trait. JSHS