Ilya11, ok, thanks for the info.
My FD tree which is old, had flowers and fruits this year that overlapped the Yuzu flowers and now I have fruits on my Yuzu grafts that should ripen in another month. In addition to the Yuzu, I have many other citrus varieties which are grafted on my old Bearss lime tree which is only 10 feet away from this FD tree. On the Bearss lime tree I have Sumo, Eureka lemon, var. Valencia orange, var. Hamilin, var. Blood orange, Australian finger lime, Hybrid key lime, Sanbokan, Pink Lemonade, NZ lemon, Tarocco #7 blood orange, Prague Citsuma, Kabosu, Satsuma mandarin, Harvey lemon, and Volckamer lemon. Some are fruiting, would any of these naturally cross with my FD?