Multiple Introduction Events of Cultivated Diospyros Kaki L. of and Native Diospyros Species in Taiwan Inferred by Low Copy Nuclear Markers

Abstract

Diospyros kaki L. is one of the most important fruits in Taiwan. Cultivated D. kaki cultivars are classified into four types, according to their loss of astringency in ripening fruit and their change in flesh color, namely the Pollination-Constant Non-Astringent (PCNA), the Pollination Variant Non-Astringent (PVNA), the Pollination Variant Astringent (PVA) and the Pollination Constant Astringent (PCA). Recently, persimmon breeders are paying more attention to rootstock selection for successful grafting and agricultural production. To identify suitable rootstock and to trace the origins of extant native Diospyros species in Taiwan, the 10 known native Diospyros species together with four D. kaki cultivars were analyzed by using two low-copy, nuclear-encoded DNA markers, ncpGS and PHYA. There was moderate to strong support for the major nodes within the phylogenetic tree, obtained from both the Maximum-likelihood or the Bayesian inference methods. The constructed D. kaki phylogeny using Maximum Likelihood (ML) and Bayesian Inference (BI) algorithms formed three clades. The most basal clade (clade A) comprised species distributed in the South East Asia , then species distributed in East Asia (clade B), and then D. kaki cultivars (clade C). The extant native Taiwan Diospyros species nested into clade A and B, suggesting a northward migration pattern of native Taiwan Diospyros species. In addition, the species D. oldhamii formed a sister clade with the D. kaki cultivars, suggesting that D. oldhamii may be a compatible rootstock. Lastly, D. kaki cultivars sampled from growers that were acquaintances formed corresponding subclades within clade C (C-1, C-2 and C-3), suggesting a high discrimination ability of the ncpGS and PHYA molecular markers used here.