the Hijack dodge

[digitS']

even more (unnecessary) info...

Let's introduce @Ben E Lou to the chance of a TEG hijack ... but, I'll do it a soft way in case he would take offense.

Here's my question @Zeedman , what do you (and anyone else) think of inbreeding depression in tomatoes?

Self-pollinating probably about 9 out of 10 times. Heirlooms ..! What have you got ~ 50, 80 generations. Can it be okay? A good thing? How can it be a good thing??

Steve
who once tried to pollinate different varieties of tomatoes and his awkward digitS' go in the way

 

[Rhodie Ranch]

I don't know if my tomatoes in-breed, but I have a heck of a time with the amount of available calcium in my soil.

 

[digitS']

Gee, I had to go back and correct my spelling.

Just reading about Ube Bread, made with purple yams (sweet potatoes?). Lucky that I didn't spell it "in-bread."

I mean: this isn't just related parents, usually. This is self-pollination ... I'm often very happy with hybrids but wonder if a lot of my success isn't a result of hybrid vigor. And, also wonder if I couldn't just do that myself, by crossing a couple of varieties that I like and then ... stand back! Would I have something that would do better than the parents?? Ya know, kids aren't always a disappointment and that, really, can go for an entire generation.

But then ... if they are self-pollinated, wouldn't that mean that there is a limit of undesirable genetic characteristics that could get combined and kind of trapped? Would it be like cloning or taking cuttings of the parent plant ..? Maybe I should go back to yams.


Calcium? Do you have trouble with blossom end rot, @murphysranch ? You just need a glacier to grind down everything from here to Montana for your garden soil! But ... what about the addition of agricultural lime? I have used it in my compost a time or 2, just because of some unpleasant compost ingredient. Wow! Things disappeared, quickly!

Steve

 

[flowerbug]

i don't know much about tomato breeding at all.

one reason why there is a good idea to breed new tomatoes in your own soils and location is to get plants which are more suited. unless you are lucky enough to find ones that are already productive, but then you'd not have what it is you are talking about.

if this is just an issue about how to maintain existing varieties it seems like most people would just try them and stop using them if they weren't very productive. to refresh their vigor may take some pointed cross breeding.

my own case with beans i'm finding some are not that well suited to our soils and length of season so i am trying to get them to cross breed with others that are more suited. it's been fun.

 

[thistlebloom]

Is what you are talking about called bottlenecking Steve?
I know next to nothing about plant breeding
(despite having a few books for beginners on my bookshelves ).

I remember April Manier (hmmm, she's not a member any longer?) talking about something like this when we save our own seeds and plant them year after year.

 

[Zeedman]

Although having a wide genetic base is preferable for the long term, most named OP varieties already have a relatively narrow gene pool, due to selection. That narrow genetic variation is almost the definition of what we think of as a "variety", and what makes it unique.

Out-crossing plants can suffer from inbreeding depression over time. I've witnessed this in a squash that I've saved for several generations. For out-crossing plants (especially corn & brassicas) seed should be saved from as many plants as possible, sometimes to the point where a large population is required. I may need to bring in new squash seed to refresh my favorite variety, and hand-pollinate with a pollen mixture from all plants.

Plants that are predominantly self pollinating (such as beans, tomatoes, and peppers) rarely suffer from inbreeding depression. I have a couple beans that began as a single survivor, and are still exceptionally vigorous after several generations. Likewise, I have observed no reduction in either yield or vitality, for peppers which I have grown in isolation for several successive generations. I haven't noticed a difference in tomatoes either, except for one variety which seems to be slightly less productive... and that may be more a result of soil depletion (my main plot was fallow this year, so I will be interested to see if yields improve).

An interesting point about seed saving philosophies. The conventional wisdom is that when you save your own seeds, the variety will adapt to your soil & conditions over time. I believe this to be true - to some extent, and not just because of genetics. Although I am not a geneticist (@seedcorn could probably explain better than me) I believe that two factors are involved in such improvements: genetic selection, and genetic expression. For there to be selection, there has to be variability in the genome to select from. As I've mentioned, most named varieties of self-pollinating plants are homozygous (genetically identical); so they are basically clones, with their offspring being identical to the parents. Genetic expression, on the other hand, could involve the activation of dormant genes already present, even in homozygous populations. IMO that genetic expression of dormant genes - and the improved vigor which can result from using fresh seed - are the most likely reasons that some varieties improve when seed is saved.

I wish I could give you a better answer specifically regarding inbreeding depression in tomatoes, @digitS' . I find that my struggle with successive generations of tomatoes is trying to preserve homozygosity... I keep finding the crosses that some tomato growers claim don't happen.

 

[seedcorn]

I am NOT against saving seed as I do it as well. I’m under NO illusions that I will make a better variety (it could happen). Gardener makes 1-2 different crosses and seldom uses scientific methods to determine better genetics. Breeders may make 10,000 new crosses a year to hopefully find 1 every 2-7 years. Everything is measured. F1’s also bring things to the table but not all F1’s are equal because parent lines are not equal then there is combining traits to consider.
You have dominant traits that are easy to select for but unknown number of recessive traits that may or may not show up depending upon environment. That’s why breeding is 90% science with 90% art in being able to identify visually what is wanted and a lot of pure luck..

For us, a hobby to enjoy.

 

[digitS']

I think Marshall was simply tying a tomato blossom from one plant, onto a flower of another. He never quite said that but several times said something about doing that cross-pollination "caveman style." You know, I think that it would be okay to do - if it works, it works. The flower parts are so tiny that I could hardly begin to mess with them. I know that there are guys on YouTube making it look simple but I think that small hands together with good eyesight is very necessary. There was also a problem with timing that I had. The varieties were not really blooming at the same time. Four or 5 days is a lot of time in the life of a flower.

Yes, more plants would have added to the likelihood of success for several reasons. Can't be any 10,000! I was using one of each in my backyard. In the distant garden, I have other things to do than the fiddling that I was trying to do with the 3 or 4 tomato potted plants I have room for at the foot of the backsteps. That guy KCtomato Keith Mueller is an independent tomato breeder. He had some pictures that he posted publicly showing his "garden." It's more like a tomato field!

@flowerbug , there are both hybrids and OP varieties that I'm very happy with.There is this little Kimberley that I'd like to see not such a semi-determinate. Buisson is supposed to be a French variety that some of the British grow. I don't think of it as such an amazing fruit, wishing it had more flavor. Bloody Butcher is bloody amazing! I grow it every year and appreciate it for lots of reasons --- Absolutely hate the name! It just doesn't seem honest for me to call it something else unless I can introduce some genes from something else.

I never see any changes with these 3. Especially, the Bloody Butcher has been around in plant numbers where there might have been some outcrosses. That has happened with some varieties. I have had to back up and use seed from a previous year. It's one reason that I don't want very old seed. If some varieties I'm happy with go rogue from 2018 seed, I can go back to 2017 seed in 2019. I've also tossed my seed and ordered a new packet. I don't know if I could do that with Buisson but some of these others are more common.

Bottlenecking is probably the right word, Thistle', but a light just came on about "cloning" and self-pollinating. Maybe there are some insects or molluscs or something with this ability but if you think about it - mother and father in the same organism is remarkable but then the genes would have to be identical, parent to offspring. So, I guess that wouldn't be depression or bottlenecking. I guess.

Steve

 

[digitS']

Here is a quote from a chapter I read in this book by Carol Deppe "Breed Your Own Vegetable Varieties":

"There is an extensive hybrid seed industry for tomatoes, even though they don't display inbreeding depression and thus there is no special biological advantage to the hybrids."

I was a little surprised that Zeedman didn't refer to this book by Ms Deppe and was wondering if she was wrong about this. I've wondered if she was wrong for a good 5 years, I suppose. Now, I'm wondering if she isn't absolutely right! But yes, I do have some hybrids that do wonderfully for me.

Steve

 

[seedcorn]

@digitS' sorry, that’s how many lines they may start with within a family every year. This is all they do. Most plant breeders are looking for parent lines to make F1’s with for better production. Most plant breeders don’t want a standard line as people will just replicate without paying the breeder fee.

Do the math, yo7 spend maybe 10 years to finally develop a better line. Sell it for $5 first year. After that every gardener has it free.