Genetic diversity among wild androecious germplasms of Diospyros kaki in China based on SSR markers

A lack of male flowers strongly restricts controlled pollination in persimmons. To address this problem, we collected and conserved male persimmon resources from various provinces in China in 5 successive years, from 2012 to 2017. Approximately 120 wild androecious persimmons and 10 monoecious persimmons were collected in Hubei, Jiangxi, Jiangsu, Hunan, Shaanxi, and Henan Provinces as well as Guangxi Zhuang Autonomous Region in China. To determine the genetic diversity and relationships among these androecious persimmons, as well as the relationship among Chinese persimmons, Japanese persimmons and closely related species, 47 wild androecious, 2 wild andromonoecious, 10 monoecious, and 1 female persimmons from China, 12 Japanese persimmons and 15 closely related species, were analyzed based on simple sequence repeat (SSR) markers. A total of 179 alleles and 456 genotypes were obtained from 15 loci, with a mean of 11.93 alleles and 30.40 genotypes per locus. The 87 persimmon resources investigated in this study were divided into XIII clusters using the unweighted pair group method with arithmetic mean average (UPGMA) and the androecious persimmons were distinguished completely from their closely related species. The androecious persimmons originating from the same provinces displayed a close genetic relationship and most Japanese resources could be classified into a same cluster exclusively. A C-PCNA type called 'Baohuatianshi' was genetically closely related to three Chinese androecious persimmons ("Macheng Yeshi-1", "Zhanfanghou-male" and "Qinghua-male") and two monoecious pollination-constant astringent (PCA) type ('Xiangyang Niuxinshi' and "Laojianshan-5"). These results provide useful information for the effective conservation and utilization of androecious persimmons.