Subject: Tissue culture/sustainable seeds

From: Jack Rowe <[email-masked]>
Date: Mon, 27 Oct 1997 14:13:22 -0500

Some facts about tissue culture followed by ideas for developing low-input
seeds:

Tissue culture is a type of vegetative propagation useful mainly for two
reasons: 1) many, many plants can be reproduced from a single unique
individual, and 2) since propagation material is taken from the extreme
growing tip of the plant, new plants are produced which are disease-free,
since new cells produced at the growing tip can be harvested before
existing disease within the plant can travel into them (or at least there
is a transmission lag and disease-free cells can be harvested). This is how
certified disease-free plants are produced, and in this capacity there is a
valid place for tissue culture techniques.

Tissue culture IS vegetative propagation, and as such does not widen and
stabilize the genetic base the way that sexual reproduction does, nor do
successive generations adapt to growing conditions to the same extent.
Godzillions of examples of vegetative reproduction exist wherein the entire
world's supply of a plant issue from one individual (as the Bartlett pear).
There might be a little genetic variation, below the level of "sports" or
actual mutations, between branches of a plant but tissue culturists
commonly take material from each growing tip so that more and bigger pieces
can be used. 

This leads to a critical area of permaculture and sustainable agriculture
in general... that of "sustainable" plants and seeds (as founder and
operator of Seeds of Texas Seed Exchange, my particular major area of
action). As we work toward low-input types of ag, the seeds we use will
assume a critical role, and seeds adapted to low inputs are relatively few
and far between, at least in "developed" countries. With its emphasis on
supply of nitrogen by concurrent legume growth, permaculture needs
vegetables which can produce well with lower levels of nutrient
concentration than modern varieties are bred for. Ditto the issue of water,
and the other nutrients for that matter.

In 1903, the USDA compiled a list of all the vegetable seeds available
commercially in the US. By '93, between 85% and 97% of almost all of these
varieties could no longer be found commercially or in the banks of the US
National Seed Storage Laboratory in Colorado. New varieties have been
developed in the meantime, but the difference is important. The older
varieties were developed independently of most chemical aids (no pesticides
and all fertilzers were of organic origin) and often performed very well
with little irrigation and in relatively-poor soils. Having experience
collecting and growing heirloom veggies, I can vouch for their toughness
and yield. New seeds are bred to give higher yields under high-input
conditions (or to store or ship well). Root systems have suffered --
instead of plants' having to work for their food, they are now "spoon-fed"
and anemic root systems are tolerated and even catered to. 

Following are some simple ideas for quickly developing new, tougher seeds
and adapting them to your local conditions. They are easy and quick, try
them... and please share the resulting seeds in seed exchanges or among
friends.

1) Save your own seeds from your own garden. The plants which do well for
you will produce more -- and more-vigorous -- seeds adapted to your
climate, soil and gardening habits. Their better adaptation can be
noticeable in as little as 3 or 4 generations! Select seeds from plants
which do well in your garden, neglect those that languish -- but be
selective with a broad stroke, to avoid creating too-small a genetic base.
Take from as many healthy plants as you can.

2) You can greatly-accelerate the process of selection and adaptation by
this process: Plant a little-too-thickly, establish the seedlings, and then
neglect them until some large percentage have died (not easy for some of
us, granted). After a majority have died, care for the survivors until they
produce a seed crop. After several generation of this treatment, you can
often create seeds which will grow without irrigation. Root systems,
especially, will show an marked change, becoming bigger and -- if your
subsoil is not too dense -- moving toward a better balance between fibrous
(surface) and tap roots. 

3) Try interplanting a couple varieties of the same plant (ie, two or more
peppers) which do well for you in a small area, so that they cross. Then
begin selecting from among their diverse offspring for plants adapted to
your conditions by the above methods. Or, collect seed from favorite
hybirds and begin selecting from the resulting highly-diverse generations.
Some plants don't cross to speak of (tomato, beans, cowpeas), but others do
and lend themselves to this treatment. Among plants which don't cross, you
will still get better adaptation just by collecting and replanting your own
seeds. Crossers include most veggies: peppers, okra, lettuces, etc. Some
will give wild results, as the Brassica oleracea group which includes
collards, cabbage, broccoli and cauliflower all in the same species.
Others, such as peppers, cross fairly slowly and usually give usable
results (hotness in peppers seems to be dominant, by the way). 

Some good books on these subjects: 

HOW TO BREED YOUR OWN VEGETABLE VARIETIES, Carol Deppe. This fun book for
home seed-breeders is both basic and thorough. Gives many ideas and
techniques not only for breeding new varieties but also for recognizing and
selecting desired characteristics from existing seed stocks. Very readable.

SEED TO SEED, Suzanne Ashworth. Seed Saver Publications, Decorah, Iowa. An
excellent resource for information on saving seeds from all the common
vegetables. Non-technical information is clearly presented on distances for
avoiding crossing, harvesting and cleaning techniques, etc. The basic
seed-saver's reference.

SHATTERING - FOOD, POLITICS AND THE LOSS OF GENETIC DIVERSITY, Pat Mooney
and Cary Fowler. An in-depth look at the political, economic and
agricultural relationships between humans and their food plants. An
excellent, well-documented, intriguing book.

ENDURING SEEDS, Gary Nabhan. Written by the ethno-botanist founder of
Native Seed Search, this book is an interesting tour through the topic of
food plants, centering on seeds and their evolving relationships with the
humans who grow them. As other of Gary Nabhan's books, interesting,
readable, simultaneously enlightening and heartening.

Also:

The Permaculture Seed and Plant Exchange
3020 Whiteoak Creek Road
Burnsville, NC 28714, USA
phone: (704)-675-5664

Seed Savers Exchange
3076 Winn Rd.
Decorah, IA, USA

The Seed Savers' Network, Box 975
Byron Bay, NSW 2481, Australia.
Tel only: 61 266 857 560
Tel and Fax also: 61 266 856 624
Email: [email-masked]
World Wide Web: http://www.om.com.au/seedsave

Seeds of Texas Seed Exchange
PO Box 9882
College Station, TX  77842
[email-masked]

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From: [email-masked]
Date: Mon, 27 Oct 1997 20:16:59 -0500 (EST)

Jack, et al

By tissue culture do you mean meristem processing only?

Milo Clark
Berkeley CA USA

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From: Jack Rowe <[email-masked]>
Date: Tue, 28 Oct 1997 11:19:10 -0500

Yes, good point, there are other types of tissue culture but I was
referring to apical meristem, the furthest-out tissue on growing tips.

Jack