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  • From: Paul Bucciaglia <pbucciaglia AT yahoo.com>
  • To: market-farming AT lists.ibiblio.org
  • Subject: [Market-farming] Re: limits of DNA testing of garlic
  • Date: Sun, 20 Mar 2005 21:40:02 -0800 (PST)

the actual journal article under discussion can be found at:

http://www.garlicseedfoundation.info/JASHSgarlic.pdf

I don' t think the conclusions of this paper science pit scientific knowlege
against farmer knowledge....

I took a quick look at the garlic paper and the authors are careful to make
an important point: they are only testing a small number of genetic sites
with the AFLP analysis they use, there could be (and probably are) genetic
differences that are present between the strains that are not detected by the
test. What it does point out is the obvious: there are many garlic
'varieties' that are genetically identical or nearly so but were renamed
because they look different when grown in a different environment. When I
got to my new farm in 2002 I trialed 6 kinds of garlic. Just looking at them
I broke them down into white/porcelain and rocambole types. The next year I
could find little difference in taste or performance between most of the
rocamboles or most of the white/porcelains. However the two types were
distinct. I think its also important to factor in seed source, and it will
take a few years of saving seed grown in the same field in the same way to
truly compare
varieties. German white and German extra hardy were shown to be in the same
group, or clade, in that analysis. This does not mean they are guaranteed
100% identical, although they could be. They may also be just extremeley
similar. On my farm, german extra hardy had much better emergence through
the heavy mulch I use and outyielded german white as well-HOWEVER the seed
stock was from different farms so I couldn't tell weather the differences
were genetic or environmental or both (ie. if you get huge bulbs/cloves of
one varieity and pit them agains medium bulbs/cloves of another varieity, you
will get skewed results!!!). Its these kinds of complications that make
diffinitive statements a rarity in the market farm. You really need very
well thought out controls, standardized treatments/environments, and
replication, within each year and over several years. Since you rarely get
any of that on the farm one does an informal kind of 'mental sorting' to get
a picture of what is
working well and what is not. Great care is required when interpreting or
communicating results that are gathered in this fashion. For those taking
advice, caveat emptor.

There may be phenotypic (physical) differences that we, the farmers may see
between some varieties, that the scientists did not pick up in that
particular test. However, the data does help one to sort out
possible/probable duplication in named varieties.

Another thing to keep in mind is that any differences in protein sequence in
a strain would have a corresponding change in DNA. The catch is that there
are many millions of base pairs of DNA in a genome. The tests the
scientists used is kind of a quick 'survey' of the DNA differences between
varieties, and would not pick up all differences. The scientists, loving job
security ;-), would be quick to add that with further testing they could run
lots more AFLP tests to determine just how similar 2 varieties are.

I currentley grow 80% german extra hardy
and 20% Italian purple, mostly in honor of the homeland :-)
If I was a better businessman i would grow all GXH!

Paul Bucciaglia
Fort Hill Farm
New Milford, CT

Zone 'MUD'!!

------------------------------

Message: 5
Date: Sun, 20 Mar 2005 14:23:00 -0500
From: "Alliums"
Subject: [Market-farming] Garlic Renaming
To: "'Market Farming'"
Message-ID: <0IDO001U10IF7540 AT vms048.mailsrvcs.net>
Content-Type: text/plain; charset=US-ASCII

Hi, Folks!

Allan wrote:

<< Let me ask you
this: If all Porcelain is genetically identical, why do some
'porcelains' out perform others...even on the same soil? >>

As someone who has several Porcelain strains and dropped MUSIC because
GERMAN EXTRA HARDY outperformed it, I'd love the answer to this question,
too. Stern was pretty adamant that it didn't matter -- he says that the
MUSIC I dropped had identical DNA to the GERMAN EXTRA HARDY that I've
maintained.

I suspect that there is more going on in subtle protein differences, mineral
availability, etc that we just don't know yet. I'm hoping that Gayle Volk,
like lots of government researchers, will be putting all of her research on
a website so we can all read it in detail and discuss it among ourselves --
if I find out the URL, I'll post it here.

For those of us who have trialed varieties and maintained collections, there
are a lot of unanswered questions here and I think we need to do the
research and questioning needed to get some answers. . .

Dorene

Dorene Pasekoff, Coordinator
St. John's United Church of Christ Organic Community Garden and Labyrinth

A mission of
St. John's United Church of Christ, 315 Gay Street, Phoenixville, PA 19460








  • [Market-farming] Re: limits of DNA testing of garlic, Paul Bucciaglia, 03/21/2005

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