Plant Sex: Open Pollinated, Hybrid and GMO Seeds

Plants have sex and make babies. Oh sure, not in exactly the same way you or I do, but I understand it’s very satisfying if you are a plant.

How’s your 7th Grade Biology? First of all, and I don’t want to shock you here, but flowers are a plant’s reproductive organs. Flowers are how plants get busy. Let that image linger in your mind the next time you see someone face-deep in a rose, taking in the intoxicating fragrance.

The way flowering plants (angiosperms, which is pretty much all that matters from a vegetable gardener’s perspective) have sex is through the exchange of pollen. Pollen is basically really lightweight plant sperm. This gets transfered from the stamen (boy plant parts) to the pistil (girl plant parts) through insects, birds, wind, or the gardener’s paintbrush.

Transfer of pollen from the stamen to the pistil leads to fertilization and the making of seeds (plant babies) inside an ovary. If this all sounds fairly analogous to what you are personally familiar with, it should. The basics of sexual reproduction are similar everywhere.

Just like kids get genetics from mom and dad, and can take after either parent but will end up their own unique person, seeds get genetics from their parent plants, and will end up with a blend of inherited characteristics. A bee could carry pollen from the stamen of an acorn squash plant to the pistil of a zucchini and whatever seeds came from that union, if saved and planted, would grow into a (culinarily useless) zucchorn or acornini. I’ve grown accidental zucchorns, and I don’t recommend them.

Here’s where plants can do it a little differently. Some plants keep all their male parts and female parts together in one flower. These plants are called bisexual or perfect. Some plants grow flowers that are all male or all female, and some plants grow both male and female flowers. If a flower is only functionally male or female it is called unisexual, imperfect or incomplete, because sexual discrimination in the plant world is exactly the opposite of that in the people world.

Okay, so now you have a pretty good idea of how plants have sex. But, other than vegetable voyeurism, why should you care?

As a vegetable gardener, you care about seeds. You buy them, plant them, nurture them and curse when, 36 hours after hard-fought gemination, the goddamn slugs eat all the sprouts emerging from them.

As I mentioned in Monday’s post about decoding seed catalogs, seed sellers distinguish between Open Pollinated (OP) and Hybrid (F1) seeds. To understand the difference, you have to understand that what distinguishes these types of seeds is the type of plant sex partners their parent plants were allowed to have.

Open Pollinated Seeds

The seed catalog doesn’t distinguish, but there are basically two kinds of OP seeds. The first is self-pollinating. Many OP seeds come from self-pollinating plants that have perfect flowers. These plants can take care of their reproductive business in house, so to speak, and the seeds that develop from them are very consistent with the traits of the parent plant. These kinds of plants, which include tomatoes, pepper, beans, peas and lettuce, are the easiest choice for the home gardener who wishes to save her own seed.

The second kind of OP seed requires outside help for pollination. Flowers may be perfect or imperfect but cross pollination between varieties is possible or likely. To get reliable, varietally accurate seed from these plants requires a little more work.

Cross pollinated OP seeds are grown by allowing seed development within a big swath of the right variety of plant. All reputable seed growers do everything they can to prevent the dreaded zucchorn squash seed. They isolate varieties, screen off growing areas or time the introduction of pollinators into dedicated spaces.

Growing good OP seed requires good roguing, which is basically yanking up any plant that doesn’t look perfect before it can contribute its genetics to the next generation. But, within the confines of the varietal isolation and roguing, the pollen swaps pretty freely, and some minor variation from child seed to seed is to be expected. I see this all the time with my flat leaf parsley. It’s all parsley, but from plant to plant the leaf shape can vary tremendously, from wide with shallow lobes to deeply cut, long leaves that almost look like slightly frilly tarragon.

Hybrid Seeds

If OP seeds are bred by only allowing a plant to have sex with other plants that meet the parent’s grower’s varietal and quality standard, then hybrid seeds are the result of a full on arranged marriage. And not just any old arranged marriage, but the kind that certain countries might opt for in order to breed super strong or super tall athlete children to represent them in the Olympics.

How about more terminology? F1 means “First Filial Generation” or the first generation gotten by crossing two distinct strains of plant. The grower of F1 (hybrid) seeds uses two, often quite different, “elite” varieties that are bred to be really, really good at certain, different things, like early ripening, disease resistance, a certain color or flavor. These parent strains basically have all the heterozygous genes bred out of them. They are 90% or more homozygous, so nothing unexpected is going to show up in their seeds.

This is kinda like how, if two Japanese people with black hair have a baby, the baby will be born with black hair. There are basically no recessive genes for blonde hair in the native Japanese population that might pop up and surprise the happy parents with a towhead.

Those two highly homozygous strains are then bred together to get an offspring that has its own set of desirable characteristics. This is a bit like if a brilliant physicist and a world class poet have a kid. The kid might not be a brilliant physicist/poet exactly, but chances are good she’ll be pretty amazing in her own way and won’t suck at creative writing or science.

Because the parent plants are so strongly homozygous, the seeds bred from these plants are extremely uniform. If you grow 12 F1 cauliflower plants, they will tend to all be ready within a day or so of each other. They will tend to look the same and grow the same.

To get these seeds, hybrid pollination is highly controlled. Sometimes hand pollination is necessary. Getting the initial parent stock sufficiently inbred without introducing unwanted genetics takes time and labor. For all these reasons, F1 seed tends to be a lot more expensive than OP seed.

Seed savers stay away from hybrids because F2 seeds – the children of F1 plants – are a total crap shoot. You have no idea what you are going to get, but it will probably be wacky. Like, beets that don’t bulb and cabbage that won’t head wacky.

So if you buy hybrids, you have to keep buying hybrids, and this is the main complaint many people have of them. Hybrids don’t allow for seed saving independence, something to keep in mind if that is your goal. As for me, I grow and use both hybrid and OP seed depending on the need and the varietal.

Genetically Modified Organisms

Pet peeve: people who confuse GMO seed with hybrid seed. So let me be clear, hybrid does not mean GMO. A GMO seed “possesses a novel combination of genetic material obtained through the use of modern biotechnology.” (Wikipedia) What this may mean is the introduction of DNA from something that is most definitely not the plant, like fungus, seafood or bacteria genes, into the genome of that plant.

Non-native DNA is introduced in order to provide a plant with a trait, such as “improved shelf life, disease resistance, stress resistance, herbicide resistance, pest resistance, production of useful goods such as biofuel or drugs, and ability to absorb toxins, for use in bioremediation of pollution.” (Wikipedia)

Critics, including me, are skeptical of whether genetic modification of food crops has been sufficiently studied for safety, and question the ethics of a company that simultaneously markets seeds that are resistant to glyphosate, a common broad spectrum herbicide, and the herbicide itself, marketed as Round-Up. I support full GMO labeling, regulation, and the ability of farmers to get recompense when their non-GMO crop is contaminated.

But from a home gardener perspective, GMO seeds are far, far more rare than the periodic “There is GMO in my Seed Catalog!” freak-out would imply.

Consider this: GMO seeds are expensive. They are patented. They are sold to farmers who, in buying them, have to sign paperwork swearing that they will not save seeds from their crop. (“Growers who wish to purchase and use our patented seed must have a signed a valid Monsanto Technology/Stewardship Agreement” – Monsanto.) If Monsanto believes a farmer is growing GMO seeds illicitly they send the Seed Police (I didn’t make that phrase up, that’s Monsanto’s term) to investigate and -ahem- “settle” the matter.

Some people allege that, when farmers growing traditional or organic crops in fields adjacent to GM crops are trespassed upon by the GM DNA containing pollen, Monsanto laywers come after them for intellectual property theft. You gotta admit, that kind of chutzpah takes serious stones, but in fairness I couldn’t find a record of Monsanto actually doing this – if you know of an actual case of Monsanto suing over cross contamination, please link to the article in the comments. Edit: NWEdible readers have listed numerous links about this topic. See the comments for more. Thank you, community!

Bottom line: Monsanto and other seed biotech companies are not fucking around. They want to maintain control over who grows their GM seed and they do not want their “proprietary technology” diffused and uncontrollable in backyards all over America. There is simply no profit in that for them.

If you are buying GM seeds, you know it. And backyard growers aren’t buying GM seeds. To the best of my knowledge, no GM seeds are being marketed to the home gardener market, though Monsanto subsidiary Seminis is publicly marketing the “Performace” series of GM sweet corn to market growers.

I really wish everyone would stop freaking out about their non-existent GM lettuce. The stuff you are buying in a seed packet is not (deliberately) genetically modified. They stuff you are buying in a bottle of Coke or a bottle of Caro Corn Syrup, or any food product containing non-organic corn, soy, canola oil or cottonseed oil is. Sugar beets aren’t far behind. The alfalfa that feeds the cows that make your milk, butter and ice cream is almost certainly GM. Wheat is on the short list for genetic modification, if only Monsanto can convince growers and consumers they want their staff of life a little… “improved.” Major field crops are where the money and the GMOs are.

Now, here’s the one caveat I’ll add to my claim that there are no GMO seeds in your seed catalog. It goes back to – you guessed it – plant sex. Once GMO crops are initially created with their transgenic DNA, they are grown out for further seed just like any other crop, and as far as I can tell most (all?) GMO seed is grown out open pollinated.

This means that it is possible that pollen from a GM plant let go to flower (say, canola) could, through the glorious act of plant sex, tickle the pistil of a non-GM canola plant being grown down the road that also happened to be in flower. Seed from the non-GM canola would then contain the transgenic GM DNA, but whomever saved that seed would have no way of knowing.

I don’t really have a good solution for gardeners worried about GM contamination of their seeds. Seeds of largest concern for the backyard grower are corn and soy, though I’d say beets and chard will be highly at risk in the future. In the end, buying good seed – whatever that means to you – really comes down to knowing your seed house, ensuring that they hold the same values you do for seed quality, and asking questions.

Did this clarify the differences between Open Pollinated, F1 Hybrid and GMO seeds? If you’ve got any questions, or have something to add, please help build on this info in the comments.

All images: Wikipedia, Creative Commons

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