Hybrids & Heirlooms
As you review seed catalogs and make
selections, you may be confronted with the terms hybrid, open pollinated,
and heirloom. Knowing what these mean will help you know more about
the plant and what to expect.
Crossing specific parent plants produces a hybrid seed (plant)
by means of controlled pollination. These hybrid seeds are often
called "F1" or "F1 hybrids." The terms "hybrid" and "F1" are strictly
defined in the seed industry and, when used in seed catalogs, do
not apply to plants crossed in the wild.
Some people think of a hybrid as blending two different plants,
like mixing a red flowered plant and white flowered plant to get
a pink flowered offspring. Unfortunately, the laws of genetics prevent
it from being that easy. Most hybridized plants require the cross
breeding of carefully chosen parent plants. The resulting seed will
produce plants with very specific characteristics. Hybrid plants
are very consistent from plant to plant and year to year. Hybrids
carry a combination of traits from the parent plants.
Based on desirable traits, breeders select specific male and female
parent plants. The plants selected to be the female seed-bearing
partner have their pollen bearing anthers removed. They receive
pollen only from those plants selected as their partners. By controlling
the pollination, the resulting offspring will have identifiable
genetic characteristics from both parents.
Producing hybrid seed is more time consuming and expensive because
the plants must be hand pollinated. In addition, plant breeders
may work for years to find the right combination of desirable traits
they are looking for in a plant.
The breeder of the F1 hybrid variety can be the exclusive source
of that variety. Only the breeder knows exactly what two parent
plants are needed to produce the seed. Other breeders can try to
duplicate a hybrid, but only the first breeder knows the exact combination
used. Of course, it is through the process of trying to breed new
and better varieties that unexpected new ones are found.
Not every F1 hybrid is a winner. The All America Selections program
and other trial gardens are ways that new varieties are tested side
by side to see what, if any, improvements have taken place in a
certain type of flower or vegetable. Before a variety reaches the
market, seed companies perform their own trials, and many hybrids
end up in the compost pile, never to be seen again.
The extra work needed to produce hybrid varieties usually means
higher cost. Are they worth the price? Consider the advantages and
disadvantages of hybrids. Hybrids possess wider adaptability to
environmental stress and are more uniform from plant to plant than
non-hybrids. Other benefits of hybrids may be earlier flowers, higher
yields, improved disease resistance, or other characteristics. Many
hybrids are better, more consistent garden performers.
The extra vitality in hybrid plants is called "hybrid vigor." More
plants survive the seedling stage, grow larger and stronger than
non-hybrids, and have higher yields. Improved disease and insect
resistance means fewer pesticides have to be used in the garden.
The primary disadvantage of hybrids is the seeds cannot be saved
from year to year. Seeds saved from hybrid plants usually will not
produce the same plant the following year because most varieties
are not self-sustaining. Offspring of hybrids usually show an unpredictable
mixture of characteristics from the grandparent plants instead of
being similar to the parent.
Some gardeners feel that the taste of hybrid vegetables does not
equal that of heirloom varieties. But taste is so subjective that
there does not seem to be a fair test to compare hybrids developed
for the home garden to heirlooms. Burpees Big Boy,
Celebrity, and Early Girl tomatoes, Sweet
Success cucumber, and Premium Crop broccoli are
examples of F1 hybrids that have been popular for years.
Open-pollinated, also known as heirloom or standard, plants are
varieties that have stable traits from one generation to the next.
Open pollinated plants are fairly similar to each other but not
as uniform as hybrids. Because most were originally chosen for only
one or two specific characteristics, individual plants of older
heirloom varieties may differ greatly in size, shape, or other traits.
Open pollinated varieties are usually grown in fields where they
self and cross-pollinate. Wind and insects carry the pollen from
one plant to another. Plants that cross-pollinate must be isolated
from other plants of different varieties so they will produce seed
that is "true to type." Beans, lettuce, peas, and tomatoes are self-pollinating
so they are easier to continue year to year without having to isolate
them from other varieties of plants.
Genetic "drift" can occur over a period of time. Plants that deviate
too far from the accepted standard are removed from commercial nursery
fields of open pollinated varieties. Likewise, home gardeners should
destroy highly unusual plants if you are trying to preserve an open
pollinated variety. Removal of these rogue plants prevents them
from pollinating other plants and producing too much variation.
The advantage of open pollinated seeds is that the home gardener
from year to year and generation to generation may continue heirloom
plants by careful seed saving. Open pollinated plants provide a
larger gene pool for future breeding. Well known open pollinated
varieties include Kentucky Wonder pole bean, Scarlet
Nantes carrot, Black Beauty eggplant, Black
Seeded Simpson lettuce, California Wonder pepper,
and Brandywine and Roma tomatoes.
As a gardener you may choose hybrids, heirlooms, or a combination
of both types for the garden. Compare the characteristics of each
variety with the qualities you want in a plant. Select varieties
that are best for your garden.
February - March 2001: Hybrids & Heirlooms
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