Sexuality of Persimmons

Based on the sexuality, commercial cultivars of persimmon (Diospyros kaki) can be classified to three types, 1) cultivars with only female flowers, 2) cultivars with female and male flowers, and 3) cultivars with female, male, and hermaphrodite flowers. For the artificial control of sex expression, it is necessary to clarify the genetic and molecular basis of sex expression in persimmon. However, the complicated polygamous sex expression in persimmon makes it difficult to elucidate the molecular basis of sex expression in in this fruit species. To understand and elucidate the molecular basis of sexuality in persimmon, we have been using one of the diploid dioecious species closely related to persimmon, D. lotus, as a model. In this study, we confirmed male and female floral differentiations of persimmon and D. lotus were quite similar and thus D. lotus can be a good model species to study sexuality of hexaploid persimmon.  Using 62 F₁ offspring segregated into distinct male/female phenotypes, we found two amplified fragment-length polymorphism markers, DlSx-AF4 and DlSx-AF7, which cosegregated with maleness. This could suggest that the sexuality of D. lotus is controlled by a single gene/haploblock, and the male is dominant over the female. Thus, sexuality of D. lotus can be described as the heterogametic male type, the XY-type. DlSx-AF4S could distinguish D. kaki cultivars with female and male flowers from cultivars with only female flowers, strongly indicating that the same genetic system controls the sexuality of D. kaki and that DlSx-AF4S could be used as a genetic marker for sexuality in D. kakibreeding programs. Based on these findings, we recently have identified the male determinant in the Y-chromosome of persimmons.