Origins of early-flowering cherry cultivars, Prunus × kanzakura cv. Atami-zakura and Prunus × kanzakura cv. Kawazu-zakura, revealed by experimental crosses and AFLP analysis

Flowering cherry trees (Prunus subgenus Cerasus) are characterized by beautiful flowers along with the existence of hundreds of flower ornamental cultivars. The long history of cultivation of flowering cherries, however, has caused significant confusion over names and origins. We conducted experimental crosses and AFLP analysis to reveal the origins or parentages of early-flowering cherry cultivars, Prunus × kanzakura cv. Atami-zakura and Prunus × kanzakura cv. Kawazu-zakura. Multivariate analysis based on pairwise genetic similarity (principal coordinate analysis; PCoA), and Bayesian statistical methods to find genetic group (STRUCTURE analysis) and to classify samples into different hybrid classes (NewHybrids) clearly demonstrated that (1) Prunus × kanzakura cv. Atami-zakura is the F1 hybrid between P. jamasakura and P. campanulata, and (2) Prunus × kanzakura cv. Kawazu-zakura is the F1 hybrid between P. lannesiana var. speciosa and P. campanulata. The experimental crosses revealed the significant difficulty of generating these hybrids. In addition, 18 of 20 and six of six samples of Prunus × kanzakura cv. Atami-zakura and Prunus × kanzakura cv. Kawazu-zakura, respectively, are classified into a single AFLP genotype. It is apparent that the original trees or genets of these taxa have long been propagated by grafting over several tens to one hundred years.

► Prunus × kanzakura cv. Atami-zakura is the F1 hybrid between P. jamasakura and P. campanulata.
► Prunus × kanzakura cv. Kawazu-zakura is the F1 hybrid between P. lannesiana var. speciosa and P. campanulata.
► Genotypic diversity of these cultivars is extremely low.
► The original trees or genets have long been propagated by grafting.