I published a video on how to cross-pollinate tomato plants. I was a little taken back by some of the criticism I received. One viewer said, “We are trying to prevent cross-pollinations. Why would you do it on purpose?” Other objections include concerns over GMO, corruption of the plant, and so on.
While reading these critical emails I thought, Hmmmm. I wonder if I should post an article on this topic? There might be a little misinformation going around that I ought to dispel. Since some gardeners don’t know the difference between GMO and Hybrids, we should begin by explaining the various differences. In doing so, it will be clear what value growers find in ‘mixing up the gene pool’.
The word heirloom means: A valuable object that has belonged to a family for generations.
When it comes to plants, the word heirloom implies that the breed has been available for generations. It is an established breed and hasn’t been mixed with other breeds from the same plant type. In this article, I’ll be focusing on my favorite plant, the tomato.
An heirloom tomato is one that is an established variety that has been grown for many years. But keep in mind, no variety is ‘the original’. Many heirloom varieties have originated from various countries where they have been separated from other types and growers have saved seeds from desirable fruit. Over time, tomatoes from Russia greatly differ from tomatoes from America. That’s also why Italian breeds have traits that vary greatly from ones grown in Australia, China, South America, and so on. As people migrate around the world and move to new lands, sojourners take their favorite tomatoes with them.
When a grower raises a plant that has unique qualities that are desirable, such as flavor, size of fruit, disease resistance, heat or cold tolerance, etc., they select seeds from that plant and carry those seeds into the next growing season. Even without intending to grow a new variety, plant changes will occur over time. Because the variety has been consistent for generations of growing seasons, it is considered an heirloom. It is not cross-bred; but that doesn’t mean it hasn’t changed.
Once a variety has been stable and grown for long periods of time, it is considered an heirloom. Even though several varieties may have a common ancestor, they can vary greatly over time by selective planting and harvesting. That is why there are so many options among heirloom varieties.
Purist growers claim that heirlooms are the only source of true genetic diversity, but this is not always the case. Genetic depression occurs in some heirlooms when various genetic traits have been lost due to selective harvesting of seeds. Many heirloom varieties have limited production, lack disease resistance, and lack many of the traits once present in their genetic past.
One great advantage to heirlooms is their stability. The seeds you harvest will produce new plants mostly identical to the parent. Variations still occur, but the longer a variety is stable, the less likely it will produce a different trait than the parent.
Stable varieties are valuable when attempting a cross-bred hybrid.
A hybrid is NOT the same as a GMO. A hybrid is created when the pollen of one variety is used to pollinate the stamen of a different variety. While some varieties of heirlooms were derived by growers keeping only the seeds from their favorite plants, other heirlooms began as hybrids. Once a hybrid is stabilized, it is no longer considered a hybrid and in future generations, it will be considered an heirloom.
Some hybrids are cross-pollinated hybrids of previous cross pollination. Some are two varieties with desirable traits. The tomato breeder might pick out a highly productive tomato, and pollinate it with a variety that is disease resistant. Or one that has a flavor he or she desires. Or a plant that is more compact.
The breeder takes the pollen from one variety and pollinates the stamen of another. In some cases, using the female from one plant will have different results than cross pollinating the female of the other plant – even though it is the mixture of the same plants.
Cross pollinating will not affect the fruit that is produced, but it will affect the seeds within that fruit. When the seeds are harvested and planted, they will produce a plant and fruit that is a combination of both parents. Depending on the varieties, there may be different results from the same batch of seeds. Other hybrids will consistently produce the same results when two specific varieties are crossed.
The first set of seeds from the cross pollinations are known as an f1 hybrid. F1 indicates that it is the direct offspring of the original cross. Once those plants produce fruit, the seeds can be harvested and replanted. The next generation will be known as an f2-hybrid. The next harvest and replant will be the f3-hybrid.
F2 seeds are when the process of de-hybriding a variety begins to take place. A breeder will grow a large number of seeds and only keep those that closely resemble the cross they were looking for. The dehybriding will continue on the f3 generation. More of the seeds will resemble the desired result, and those seeds will be harvested and seeds from the undesirable plants will be discarded. By the fifth generation, the breed will become mostly stable, but some plants will revert back since it takes a while to weed out the genes that don’t fit the goal of the grower.
Some hybrids revert fully. Others are unable to reproduce. Others still produce a mixture of results, allowing the breeder to locate desired plants.
The advantages of hybrids should be obvious. It allows growers to obtain a combination of flavor and productivity, productivity and disease resistance, plant size and tolerance, or any number of combinations.
Another advantage is that when genetic information is lost, it can be reintroduced to future generations by crossing a favorite heirloom with needed traits.
There is much controversy over GMO plants – or Genetically Modified Object plants. Instead of selective breeding or cross pollinating, desired traits are engineered into the plant by artificial means. It is man-made introductions in the lab. GMO plants allow corporations to select specific traits and even turn off certain traits in the lab.
This allows manufactured seeds that can produce food but not seed that can reproduce the next generation. Sterile seeds force growers to keep buying from the supplier, instead of saving seeds and replanting. It also allows companies to introduce intellectual property rights into the genetic code, thus allowing them to patent lab-created seeds.
The information I struck through above came from a source that presented inaccurate information. The intellectual property rights is the issue at hand, not the inability to reproduce. Because there is so much misinformation and people need to make informed decisions, I posed several questions to Carly S. at Monsanto. She clarified the issue with the following:
GMO is not used to develop sterile seeds. …I know for a fact that none of Monsanto’s biotech seeds are “terminator seeds”. Although the reproduced seed may not always contain all the same characteristics of the original seed (much like what happens to the seeds from hybrids), this is not what “forces” growers to keep buying the same seeds from seed companies. What does keep farmers buying from seed companies is the technology use agreement that they are required to sign to purchase the seeds. This agreement states that they will not save their reproduced seeds for future planting. This is much like the laws around music and software. Companies must patent their technology, especially if it is self-replicating, to protect their intellectual property. Otherwise, they are spending millions of dollars to only sell the product once.
For more information on Terminator Seeds, see the article at http://www.monsanto.com/
Critics claim that genetically modified food could be harmful for consumption, and many fear that genetic engineering is man playing God in the lab.
I’ll leave this for others to debate.
GMO is lab-created. Hybrids are insect or gardener cross-pollinated. Hybrids are no different than what happens in nature. Bees introduce pollen from one plant to the other. Creating a hybrid is being intentional about cross pollinating instead of hoping a bee will do it for you.
And now you know.
For more information on GMO, visit my article, GMO and the Gardener – Should we be afraid?
Eddie Snipes 2013