University of Illinois Extension

 


Barbara Larson
,
Unit Educator, Horticulture
Boone & Winnebago Counties

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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. ‘Burpee’s 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 | Put the Right Plant In the Right Place | Windbreaks Can Help Save On Energy Costs | Apple Scab & Black Knot

 

Past Issues

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