In a message dated 10/21/2009 10:21:47 PM Central Daylight Time, abb7@Lehigh.EDU writes:
I?d guess that two varieties which are both from Japan are more
closely related to each other than they are to a variety from Korea or
China.
Hi Alex,
I believe the most distant relatives would be in China. From what I've read kaki originated in that area was carried form there to other parts of the world. And yes, I believe breeding in Japan was to improve fruit not improve winter hardiness. But breeders in Korea may have done more to improve winter hardiness than China.
Great Wall supposedly has more winter hardiness than most other varieties, but it didn't survive here planted next to my house on the South side. I have one of Cliff England's varieties here that survived about -5 last winter, it's second year here.
One more thing, I've read that generally the astringent varieties are more winter hardy than the non-astringent.