On Oct 18, 10:58*pm, An Sonjae > wrote:
> If one does a Google search for tea +genetic +DNA the results suggest
> that quite a lot of research has been done on the DNA of tea, and that
> is only seeing the English, while I rather think that the main bulk of
> studies will have been published in Japanese, as well as Chinese and
> Korean. Some interesting stuff there, including the discovery that
> wild tea in Korea has 2 clearly defined origins, one Chinese (ancient)
> and one Japanese (recent).
>
> Br Anthony

Certainly some interesting stuff exists as you say but 'a little' and
'quite a lot' are relative terms. I was comparing DNA taxonomy work
with the wealth of health work in tea. As a crude tool, Google tea
+genetics+DNA scores 308,000 results but tea+genetics+DNA+damage
scores 263,000, netting but 45,000 for botany to some 85% for
medicine.

Having established that, and allowing serendipity her head, I came
across a paper listing variations in the quality components of tea
plants in the China National Germplasm Repository. [The Chinese are
wisely collecting a huge tea gene pool as a resource for future
breeding - commercial tea culture tends to pick winners and propagate
these few, so reducing genetic variation in the field - a short
sighted technique that assumes teh fallacy that tomorrow's problems
will be the same as today's].

The quality component variations the Chinese show will baffle those
who like a simple correlation between tea type and caffeine level, or
tea type with antioxidant potential. For instance, in the CNGTR
collection, which is mainly China type tea varieties:

Polyphenol varies from 13.6 to 47.8% (highest in Yunnan types)
Catechins range from 8.2 to 26.3% (at variance with total polyphenols;
Hunan teas are highest)
Amino acids range from 1.1 to 6.5% (lowest in southern provinces)
Caffeine varies from 1.2 to 5.9% (Yunnan tends to have the highest,
China and Japanese types have similar variation)
Water extractable solids varies from 24.2 (well below ISO minimum of
32%) to an amazing 57.0% (again Yunnan tending to have the highest).

As you say, Brother Anthony, some interesting stuff !

Nigel at Teacraft