Genetic Relationship between Early-flowering Cherry Cultivars and Regional Populations of Prunus campanulata

Although many early-flowering cherry cultivars may have originated from Prunus campanulata, the origins of some of these cultivars are still unknown. Moreover, although P. campanulata is also found in southern Japan, China, and Taiwan, the genetic relationship between the regional populations of P. campanulata has yet to be elucidated. In this study, we conducted Amplified Fragment Length Polymorphism analysis to reveal the origins of early-flowering cherry cultivars from the viewpoint of both the species and regional population level. We selected 14 early-flowering cherry cultivars and three species, P. campanulata, P. lannesiana var. speciosa, and P. jamasakura, as the parental candidates of the cultivars. For P. campanulata, we collected samples from Japan, Taiwan, and China. Principal coordinate analysis and STRUCTURE analysis showed that many cultivars originated from P. campanulata. In addition, P. campanulata found in Japan, China, and Taiwan were genetically different from each other, thereby indicating the origins of the early-flowering cultivars from each region. In China and Taiwan, some P. campanulata were composed of a genetic cluster characteristic to Japan, suggesting the possibility of artificial genetic migration and/or introgression. Of the 14 early-flowering cherry cultivars analyzed, five were hybrids between P. campanulata and P. lannesiana var. speciosa and four were hybrids between P. campanulata and P. jamasakura. Three cultivars were suggested to be intraspecific variations of the original species. Furthermore, the samples of the two cultivars were composed of two and three genetic origins, respectively. To conserve the genetic diversities, early-flowering cherry cultivars and P. campanulata should be managed at the three regional levels.