Black persimmon: a very unique and valuable germplasm in China

There are more than 1000 persimmon (Diospyros kaki Thumb) cultivars in the world. However, almost all cultivars known have orange or orange red pericarp when mature, due to the accumulation of carotenoid. Surprisingly, there are some accessions in China with black pericarp during mature, named black persimmon. It is a unique and valuable germplasm. Nevertheless, the information about black persimmon is scarce. We analyzed the black pigments by ultraviolet and visible spectrophotometer. Compared with ‘Mopanshi’ (orange pericarp), black persimmon showed an additional absorption peak around 540 nm, which corresponded to anthocyanin accumulation. Determination of pigment content resulted in abundant accumulation of anthocyanin in its pericarp rather than carotenoid. We collected 15 black persimmon accessions around China. We studied the morphology and molecular markers to determine its taxonomic status. There were no spines on its branches, no glands or spots below the leaf, and no hair on the fruit. At the same time, black persimmon has large leaves (>7 cm), the length of fruit stalk was over 6mm, and the fruit diameter was about 4.5~5.5 cm. It was manifested by all morphology characteristics that it should belong to the D. kaki, rather than a new species. Its taxonomic status was further identified by 12 IRAP (inter-retrotransposon amplified polymorphism) markers and 15 SCoT (start codon targeted polymorphism) markers. Results suggested black persimmon belongs to D. kaki species and had a closer relationship with pollination constant and astringent type persimmon native to China. Meanwhile, there were high genetic variations between black persimmons. It was more likely to find black persimmon germplasm with better fruit quality. In conclusion, black persimmon was a D. kaki germplasm resource with black pericarp due to the accumulation of anthocyanin. It was a very unique and valuable germplasm for breeding different pericarp color and anthocyanin content.