Thin end of the wedge?

[Penellype]

There seems to be a tremendous amount of confusion about what hybrids, F1, F2 etc mean. At the risk of launching myself into a huge long post, let me try to explain in simple english what the plant breeders are trying to achieve.

Plants have 2 ways of reproducing, although how they do so depends on the species. The first is asexual reproduction - this is when plants form runners or suckers like strawberries, raspberries etc, or when you take cuttings which grow. The offspring plants are identical genetically to the parent, end of story. This is ideal if you want to propagate your strawberry plants and know exactly what you will get.

The 2nd method, and the one of most interest to plant breeders trying to create new varieties, is sexual reproduction. This involves plants with male and female flowers or flowers with both male and female parts. The result is a seed, which contains genetic material from both the male and the female parents.

Imagine a pea plant. They are quite variable - you can get tall ones and dwarf ones, long pods and short pods, single pods and twin pods, round seeds and wrinkled seeds, white flowers and purple flowers, edible pods and non edible pods, and a host of other variations that might not be so obvious to look at. If you take a specific variety, say Meteor, it will always have round seeds. The round seeds have become established in the variety and will never vary because every Meteor pea plant is homozygous for round seed (that means that the gene for seed shape is the round gene on both chromasomes in every plant). Similarly the other important charactaristics of Meteor (height, hardiness, earliness, white flowers etc etc) will all be homozygous so that the variety is very uniform. This is true for the important charactaristics of every established non hybrid variety. You know what you get when you plant it because it has been bred to the point that it is completely uniform in all important characteristics, and as long as it is crossed with the same variety, its seeds will breed true. You can save your seed and grow it yourself.

Now suppose that you are a plant breeder and you want to breed a specific type of pea that has the hardiness and quick growth of Meteor, but is more resistant to mildew. You have another variety (lets call it R) which is not so hardy and not so early but it is resistant to mildew. At this point I have to make an assumption which may well not be correct, but if I don't I will have to go off at a tangent to explain something else. I'm going to assume that the 3 traits we are interested in are all "dominant" and will therefore show up regardless of what the other variety is. So as a plant breeder I make sure that all my Meteor flowers are pollinated using variety R (this is difficult as peas are self fertile, which is why F1 seeds are often expensive). The offspring, which is F1, will inherit from its Meteor parent the hardiness and earliness that I want. It will inherit from R its resistance to mildew. BUT, and this is the important bit, it will also inherit but not show the recessive gene for less hardy and less early from R and the recessive not resistant to mildew gene from Meteor. In addition, although the F1 seeds will all be uniformly round (because round is dominant over wrinkled), if R had wrinkled seeds they will have the recessive wrinkled gene. There will be many other genes that are also not uniform, having one of each sort - dominant and recessive. All of the first (F1) generation will be exactly the same because they have inherited one of each from their parents, which are homozygous in all important respects. The F1s are heterozygous (one of each gene type) in many respects.

Now, there is something called "hybrid vigour" which basically means that if you get a large number of heterozygous genes you get a much healthier offspring. Think of mongrel dogs versus pedigree dogs which can be notoriously prone to specific breed related problems. Hybrid vigour can mean that F1 varieties of plants produce extra large crops, huge flowers or whatever you are trying to produce, if you get the mix right. Therefore you often find that F1s are advertised to have specific special features unavailable in the non hybrid varieties.

Now imagine what happens if you try to breed your F1s to make the next (F2) generation. Instead of starting off with a uniform set of genes in each parent, although both parents look exactly the same, the genes are all muddled up. It is absolute pot luck which 2 genes for any given trait will end up in a given seed. You can calculate the probabilities (for a simple dominant/recessive pairing for say round seed you will get 1 homozygous round and 2 heterozygous, all of which will have round seeds, and one homozygous wrinked which will have wrinkled seeds). The same ratios will apply to each of the traits involved but they will be randomly distributed - just because a seed is double round doesn't mean it will be double for hardy etc. So all of the seeds are likely to be different, and some will have many of the less desirable characteristics. Your chances of producing a seed with identical genes to both of its identical F1 parents are vanishingly small. So if you try to save seed from your F1 hybrid you will end up with very variable plants, some of which may not look at all similar to the F1 parents you saved the seed from.

By definition hybrids can't die out unless the plant population is reduced to just one totally uniform variety. If you have 2 varieties you can create a hybrid by crossing one with the other. The success of life on earth and the whole process of evolution depends on hybridization and genetic variability between individuals of the same species, and it is actually the totally uniform varieties which have been bred for generations to be exactly the same which are rather less "natural".

I hope this helps people understand a bit better what these things mean - I've tried to keep it simple at the expense of some accuracy in places.

[Alison]

Hybrid vigour can mean that F1 varieties of plants produce extra large crops, huge flowers or whatever you are trying to produce, if you get the mix right. Therefore you often find that F1s are advertised to have specific special features unavailable in the non hybrid varieties.

Although quite often I feel that the claims are exaggerated by the seed companies, one look at the catalogues is enough to see all the hyperboles used in a bid to flog us more stuff and recoup some of the development costs. Although there are some exceptions a lot of the time the refinements are more aimed at commercial growers rather than the allotmenteer, I for one don't want uniformity in my produce as it leads to unwelcome gluts.

[Aberdeenplotter]

as an exhibition grower, where uniformity is one important part of the judging criteria and where multiple similar specimens are required at the same time then F1's are an important factor in my growing.

[Thelma Sanders]

Taste doesn't come into the equation and the nutritional value is way down on traditional veg

Do you mean that F1 plants have less taste and less nutritional value than OP varieties? Cos I don't think that's true.

I do grow some F1s where they give me specific benefits - eg club root or rust resistance, but also grow OP varieties, and save some of their seeds. I just choose varieties that I think will suit my taste buds and my conditions best.

[Snadger]

Do you mean that F1 plants have less taste and less nutritional value than OP varieties? Cos I don't think that's true.

I do grow some F1s where they give me specific benefits - eg club root or rust resistance, but also grow OP varieties, and save some of their seeds. I just choose varieties that I think will suit my taste buds and my conditions best.

I had clubroot on my plot which now thankfully I've got rid of. I tried some of those F1 clubroot resistant varieties and I can tell you that 'Taste' had nothing to do with it! I personally think that in general, Fi's have less nutritional value. I don't think many F1 varieties has been hybridised for nutritional value anyway?

I can agree with AP that show winners will probably come from F1's as they are bred for weight or looks, and are probably a lot less nutritional and tasteful than OP varieties.

[Bill HH]

I have been having a rethink about F1 hybrid seeds. I grow quite a few and I thought "Why not, if they are an improvement on open pollinated varieties." Technology moves on and if we didn't keep up we'd still be shivering in caves.

F1's to me are the thin end of the wedge and I'm personally going back to traditional veg. All F1's don't come true by seed, and a lot are infertile. The plants grown from the ones that do give seed that grows, bear no resemblance to the original.
Taste doesn't come into the equation and the nutritional value is way down on traditional veg. Scientists are now starting to clone and splice animal DNA into plants and these CAN cross pollinate with existing plants. We have no idea of the long term affects of this on the gene pool!

We need a huge gene pool to give us the diversity for life to go on. Nature doesn't interbreed plants for size, yield etc, it throws up all sizss for diversity.

I fear we are sacrificing our long term future for short term gain.

One thing that does bring a smile to my face is that open pollinated seeds are usually cheaper than others anyway.

I am completely with you on this one, Firstly the seed merchants wont rest until all seeds are F1 and then we will have to buy them, once that happens they will hike up the prices. Secondly one single accident in genetic modification could produce a disaster that threatens the entire planet.
The risk of that they tell us is very very low, but my experience is that if a thing can possibly happen, however unlikey, it eventually will.

[Thelma Sanders]

Are we confusing many issues here?

F1 hybridization is 'normal' in as much as it is just crossing 2 different varieties by ensuring that only the 2 varieties are available for pollination.
There's nothing sinister about it, other than restricting the number of pollination partners to 2 varieties to give a specific result.
To save seeds yourself you need to restrict the pollination to the one variety you wish to save. Either you do it or the seed merchant does it - But without this restriction there would be no named varieties to choose from.

As with any variety that has crossed you may decide you don't like the taste - different varieties taste different. Simples.
That's why we can't ever decide on the 'best tasting' tomato variety isn't it?

Where I draw the line is genetic engineering. So far, they're not allowed to sell GM seed here - long may it continue, cos I just don't want to eat GM stuff
Oh No!

[Snadger]

I am completely with you on this one, Firstly the seed merchants wont rest until all seeds are F1 and then we will have to buy them, once that happens they will hike up the prices. Secondly one single accident in genetic modification could produce a disaster that threatens the entire planet.
The risk of that they tell us is very very low, but my experience is that if a thing can possibly happen, however unlikey, it eventually will.

Thankfully,I think we al agree GM of vegetables is a dangerous concept.

The F1 hybrid issue is one that is creeping in by the back door and slowly but surely is taking over. As Bill points out, once the seed companies have us hooked on F1's they could slowly phase out the open pollinated varieties. That will leave us with the six seeds to the packet,triple the price, F1 seed only.

[Bill HH]

Yes I do realise the FI and GM are not the same but both are interfeering with natures own well thought out and time proven methods.

My father devoted fifty years to improving Rhode Island Red poultry taking their average egg laying ability from 200 eggs per year to over 300 eggs per year, He examined every bird for a host of attributes and painstakingly recorded all the results. During those fifty years he had time to spot problems in any particular breed line. It was if you like a careful helping hand to natural selection. Nowadays the process is dramatically speeded up by genetic interference both for plants and animals with production deadlines and market pressures. In this accelerated time frame can we be sure no major disasters could slip through? Particularly in the production of plants because once released into the environment there is no stopping it.

[Chris11]

I don't necessarily disagree with some of the sentiments expressed here, but just because anyone personally believes something, or has a vague sense of unease about the direction things are going, does not make that the whole story.

As Penellype says, there is a great deal of confusion about these things. In my experience, even most traditional Biology graduates and teachers don't really understand basic genetics, so it's not surprising that everyone else struggles.

Whether it's F1s or anything else, it's not significantly different from selective breeding of plants and animals that has gone on for thousands of years with human influence, and throughout evolutionary history before that. Yes, there's natural fear and cynicism about 'big business' and control of seed supply, but like every other issue, it's not as black and white as might first appear.

I wonder how many people who are instinctively against some aspects of modern genetics have a pedigree dog? Why do you think it doesn't look like a wolf? Traditional selective breeding can be a force for bad as well as good. Advanced modern techniques are no different.

Whether it's random mutations for good or bad, or random hybrids in nature, or random exchange of genes between different species of bacteria or viruses, or random duplication or hybridisation of entire genomes leading to new species, these things already happen naturally. Although 'natural' in this context does not necessarily mean good for human outcomes.

In terms of GMO, those who are against it might find themselves in favour of it in certain cases. What if gene therapy could selectively replace faulty insulin genes to cure diabetes? What if plants could be modified for greater saline tolerance so crops could be safely grown in areas where it is currently not possible? What if bacteria could be modified to clear up oil slicks thus preventing otherwise catastrophic enviromental damage?

And the cells in our own bodies are something way more profound than a hybrid. Our 'human' mitochondria originated as an independent and separate species that merged symbiotically with our ancient single-celled ancestors. Your mitochondria has DNA closer to its ancient and modern bacterial relatives than to yours.

[BUFFS]

I cannot be bothered about F1 benefits, I am now just into my 4th year of crossing various toms and they now bear little resemblance to the ones I started with, and each year throws up a few surprises, some you keep, some you don't, but that's the fun. I show at the local show and try to put a "different" veg/fruit in each year... now trying to get my kind of beefsteak tom crossed with the indigo rose (black) crosses so that anyone looking at it will be thinking "round aubergine", so that's it, a bit of fun that tastes good and keeps me active..... and well fed, I leave all the hybridising/cloning/GM to those successful brain donors across the atlantic, I mean , have you seen that trump guy, all those shredded wheat on his head, are they GM?...

[Thelma Sanders]

I cannot be bothered about F1 benefits.........................................trying to get my kind of beefsteak tom crossed with the indigo rose (black) crosses so that anyone looking at it will be thinking "round aubergine"

You are trying to hybridise an F1 variety of your own, though lol

[spamvindaloo]

This thread seems to be going in different directions:

GM- I don't think that any of us want GM seed. And I don't think that even the more scientific amongst us are really sure that the GM scientists understand every consequence.

Cloning - we've all done this if we've ever taken a cutting

Hybridisation - this does occur in nature. Many of the open pollinated varieties will have hybridised at some point. Evolution by natural selection will lead to plants that most suit their environment (and other factors) to succeed, those characteristics may have been selected as a result of the plant having hybridised. Do I think hybrids are bad, no. Do I think that seed companies use the expense of Hybridisation to justify adding a bigger markup than they really need to, yes possibly. But I am aware that for every success, there's are probably many failures and they need to make their profit when they can. I think it's a case of you pay your money and take your choice. If you want hybrid seeds, then fine. If you don't, then that's also fine. But I think it's unfair to demonise the seed companies for developing something that a lot of gardeners want.

[Bill HH]

Yes hybrids occur naturally as does genetic modifications. The difference is these occur slowly and their effect is tempered by all he other plants/creatures competing with them. With modern methods any modification is rapidly repeated and mass produced, soon to become distributed world wide.
I am quite prepared to admit some genetic modifications are to our benefit but have little confidence in the scientists or industrialist to apply the care and caution required.
For instance, a bacteria that eats oil, what if it became so successful that it was generally air born ?Imagine filling your car up one day then coming out to an empty tank apart from a few tiny turds a note saying thank you for our lunch! I know that is ridiculous but our entire ecosystem is so finely balanced that we tamper with it at our peril.
I also question the real need for increasing yields of crops, until recently we were paying farmers NOT to produce grain (The set aside plan) We have too much milk,leading to rock bottom prices and bankrupt farmers. We have had butter and grain mountains etc. Given the proper encouragement farmers can easily feed the world using present day methods.Even on our small Island land is leaving agriculture at an astonishing rate to building and horsey culture. My own farm in the Midlands (106 acres) now produces little food because it is covered in stables and horses.
GM succeeds because it gives one farmer an advantage over another, so if one farmer uses GM seeds the rest become uncompetitive, they don't gain anything. The ones who gain are the seed supply companies. Many years ago nitrogen fertiliser became available, soon every farmer was slapping it on just to keep his yields up to the level of his neighbours. It has been an eco disaster, the nitrates filter though the soil to the water table (sometimes this takes 40 years) causing major pollution of our drinking water. Where were the caring scientist then, when they invented this stuff? Who gained? not the farmers or the public because we became over supplied and poisoned. The chemical companies gained and made fortunes and still do. Now we are supposed to place our trust in them again.

[Potstubsdustbins]

I don't like GM. We don't know enough about it.

I don't agree with man made global warming. In the 60s they were telling us to prepare for a mini ice age. That theory has raised its head again recently.

I don't agree with most dietary recommendations. Butter was bad, eat man made spread, butter is now better for you than man made spread.

I don't agree with most healthy living options after all the man who invented jogging died young whilst err jogging.

Why this somewhat strange mind set? I do believe in human nature.

So called scientists work for their paymaster and human nature dictates they will do their very best to give said paymaster what he wants.