[MOhillbilly]

OP, Hybrids and Heirloom Plants


When reading about gardening there is often reference made to the terms "OP (Open Pollinated)", "Heirloom" and "Hybrid". These terms are often misused and more often misunderstood. The problem comes mainly from the fact that except for the term "OP", the other two have no absolute definition. I will explain.

Let's start with the term "OP" or Open Pollinated. Plants that are "OP" will produce fruit with seeds that can be regrown to produce plants like the parent plants. The only requirement is that the pollen that fertilizes the plant must be from itself or another plant of the same variety. Using a tomato as an example, when an "OP" tomato like a Marglobe produces tomatoes after being pollinated by itself or another Marglobe the seeds within that tomato can be used to grow another generation of Marglobes like their parent plants. This allows you to continue to grow a certain variety of plant by collecting seeds from it. This is true as long as the flowers of an "OP" plant are pollinated ONLY by plants of that variety. Another type of tomato's pollen in a Marglobe tomato would produce a tomato with seeds that if planted would grow up a plant unlike a Marglobe in some ways since the seed would have characteristics of both parents for the most part. This is called "Cross-Pollination" or crossing one plants genetic code with another. Plants produced by cross pollination would be called "Hybrid".

"Hybrids" are plants that are created by "Cross Pollination". In other words two different varieties of a plant are grown in close proximity and the result from pollinating each other is a new variety of that plant. So if you grow two different "OP" plants in a small enclosed area, the result would be seeds that showed some characteristics of both parents, not an exact copy of either parent. "Hybrids" often produce a seed that is sterile and will not grow. "Hybrids" that do produce a viable seed may or may not produce a plant that is even like either of the parents. Genetic crossing is an inexact science and trial and error is the rule not the exception.

"Heirloom" plants are "OP" plants that have been grown in their variety for long enough period of time to be declared "Heirloom". The term is not a scientific term, but instead a gardener's term used to describe a certain history of the plant. It was coined since many families of older days would pass seeds down from one generation to another like they would pass a ring or piano down. The seeds are prized possessions of many families. An "Heirloom" plant has to be an "OP" type seed for the obvious reasons but the time it has existed and grown is debated. Some groups only consider it an Heirloom after 75 years while others have settled on 50 or even as little as 25. The point is that Heirloom is pretty much synonymous with OP, but with the added point that it has been around a while.

Now for the confusing part. Some heirlooms are actually Hybrids in a technical sense. The Marglobe tomato has been around for nearly 100 years now. It is technically a Hybrid since it was created in 1917 by the USDA by crossing a Marvel tomato with a Globe tomato. The offspring of this cross produced a viable seed that grew a copy of itself with characteristics of the parents and a few extra good things that were the result of genetic crossing. The Marglobe was the first tomato that was resistant to Fusarium and Verticillium Wilt. Quite a big hit back then and since then the Marglobe has been parent to many tomato varieties with good disease resistance. In fact the Marglobe is the United States' most popular canning tomato for about 75 years now. The Marglobe and many other plants were developed by cross breeding, but since they were able to reproduce their kind generation after generation, they have been called "OP" now and since they have done it for a while many are also now considered "Heirloom".

Summary" "OP" means you can save the seed and then regrow the same crop as long as it was not cross pollinated.


"Hybrid" means a cross breed that will probably not produce seed that would grow a plant like it came from and more often than not grow any plant worth growing.


"Heirloom" is basically an "OP" that has been around long enough to pass the test of time.

Bonus Info:

You also hear a lot of reference to "GMO" seeds. This refers to "Genetically Modified Oranisms" or plants that were produced by splicing the genetic material of various things (Not always plants, but frogs, goats, bacteria, virii, insects, etc.) by laboratories into plant genes to change the organism in ways to obtain changes that one could only dream of before. They have used frog DNA from a frog that doesn't freeze even at 0 degrees to make some plants more tolerant of low temps for example. The sky is the limit with GMO technology, and the highs and lows of potential successes and failures are seriously debated.