of Chance - The Selfers and The Outcrossers
It’s snowing seed catalogs - a veritable
blizzard at this time of year offering unlimited potential
for spring. These piles of catalogs remind me of the seed
diversity in our modern culture. Where, what to select from
this unlimited supply is a question each gardener needs to
answer. Where, what dreams to explore, what novelty to introduce,
what cultivars (G) to
give space to in a limited garden, is the quandary of each
winter. Choices unlimited are as close as the World Wide Web,
and with seeds delivered direct to the door – easy temptations
for my dreams of spring.
But what if new seeds only arrived with the
occasional traveling stranger, or came carried by hand from
other gardeners or farmers? What if the seeds I need came
only from my own plantings? How then would I approach the
promises of spring? It was not too long ago, that each garden
was mostly its own genetic reservoir, and each farmer exploited
the best plants to supply future seeds. Nor was it was long
ago that new varieties arrived smuggled in cuffs, hems and
What do I need to know in order to return to
the seed systems of yesterday? What knowledge and commitment
is required to become my own genetic reservoir - to use the
best of my own plants to reseed garden beds? And how would
I change my planting, harvest and renewal to fill both the
table and garden, today and tomorrow?
This is where we need to know the difference
between Selfers and Outcrossers - between flowers that pollinate
themselves and those dependent on pollen from others. This
single difference in flower proclivity may determine what
plants you save seed from, how you plant them and how you
garden around them.
The Selfers, or those that are mostly self-pollinating
(G), are the easiest to manage. Beans,
fava beans, cowpeas, peas, lettuce, potatoes, sweet potatoes,
garlic and tomatoes (with some exceptions,) are the common
Selfers in a kitchen garden. Peas, lettuce, beans, fava beans,
cowpeas and tomatoes have a flower structure that eliminates
or severely reduces cross-pollination. Therefore, you can
be plant them closely and harvest seeds that are mostly true
to type. With garlic, there is never any cross-pollination
as the entire group has sexually dysfunctional flowers and
potato seed rarely reproduces true to type.
All the other plants grown in kitchen gardens
are Outcrossers (mostly) that have spacing, timing and population
size requirements for producing vigorous, true to type seed.
For example, all squash varieties of one species (there are
four common species) will cross-pollinate with others of the
same species, but will not with other species (alas, again
there are exceptions). So they must be isolated by space,
time, or physical restrictions and hand pollinated. All radishes
will cross-pollinate (I know from experience), and the mustard
family is particularly complex in their sexual practices –
with some that are both Selfers and Outcrossers. All of the
onions will cross-pollinate, but will not cross with leeks.
(Top-setting onions may be an exception)
An additional complication with saving seed
of Outcrossers is their tendency toward inbreeding depression
(G), which occurs when closely related
plants reproduce with each other. It is particularly prevalent
in small populations of plants as found in kitchen gardens.
Generally, a population of 100 plants is recommended to avoid
this detrimental influence of recessive genes. Fortunately,
not all Outcrossers are susceptible, and there are ways to
work around the problem. So, growing both food and seeds from
these Outcrossers complicates the planning and management
of the kitchen garden, and forces the gardener to make choices
about which seeds to save and which to purchase each year.
In addition, the seed gardener needs to know
how to harvest, clean, test and store seeds. Fortunately,
much has been written about the hows of seed handling for
all of the common kitchen garden plants, such as the following
example for saving tomato seed:
Saving Tomato Seeds
If you plan to save seeds from you tomato plants,
make sure you have open pollinated varieties. There are many
hybrids available today as both seed and seedling plants,
which will not produce true to type from saved seeds.
There are at least 18 seed transferred tomato diseases. Do
not select fruit that are miss shaped, or show evidence of
diseases, and do not select from plants that show diseases.
Do not save seed from fruit that has fallen to the ground.
(I personally do not save seed from late blooming plants or
from late season fruit.)
Most tomatoes are self-pollinating, except for
the “potato leaf” varieties, like Brandywines,
that can cross out with other varieties. It is advisable to
isolate the “potato leaf” varieties by at least
50-100 feet for seed saving. It is also advisable to grow
a minimum of six plants in order to avoid saving seed plants
that are off types or not true to that variety.
Soaking the seeds in water until a skim of mold
begins to form on the water surface is advisable, but do not
let is go beyond 72 hours. The slight fermentation kills some
seed transferred diseases and removes or reduces substances
that inhibit seed germination. Rinse the seeds well with fresh
water and dry on a screen surface or in a fine mesh or nylon
bag. Drying them on paper or fabric causes them to stick to
the surface. Stir occasionally while drying to prevent the
seeds from sticking together. Do not dry seeds
in direct sun or at temperatures above 95 degrees F. Store
in a cool dry place and they will retain viability for at
least three years.
till next month,
Doña Ana Extension Master Gardener
Additional source of information:
Seed to Seed: Seed Saving and Growing Techniques for Vegetable
Gardeners - by Suzanne Ashworth, Kent Whealy
NOFA (Northeast Organic Farming Association)
Handbook series – The Wisdom of Plant Heritage:
Organic Seed Production and Saving - by Bryan Connolly
with contributing editor.
is a form of pollination that can occur when a flower has
both stamens and a pistil in which the cultivar or species
is self-fertile and the stamens and the sticky stigma of the
pistil contact each other to accomplish pollination.
is a cultivated plant that has received a name under the International
Code of Nomenclature for Cultivated Plants. For this, it must
be distinct from other cultivars and it must be possible to
propagate it reliably, in the manner prescribed for that particular
cultivar. Status as a cultivar is a quite limited one, with
nomenclatural consequences only; it offers no legal protection.
depression is reduced fitness in a given population
as a result of breeding of related individuals. Breeding between
closely related individuals results in more recessive deleterious
traits manifesting themselves.