Wind or bee cross pollination

[JimmyCrackedCorn]

I have been successfully saving and replanting seeds from a few varieties of tomatoes from my back yard for 4 or 5 years now. I have never bagged blossoms or isolated plants.

Today I spoke with a local extension employee who warned me that I have been doing it wrong. He said that if I have bees in my garden (I do) that the tomatoes will easily cross and I won't get what I expect when I regrow those seeds.

Have I just been lucky so far? Is this as big a concern as he was stating?

[Doug9345]

This was discussed at length here.
http://tomatoville.com/showthread.php?t=29560

[joseph]

Depends on what you want out of your tomatoes. I consider myself a very lucky farmer whenever a natural occurring hybrid shows up in my garden. To me, the more genetic diversity the better. I am working on converting my tomato patch into a promiscuously pollinating population by selecting only for plants that are very attractive to bumblebees, and that shed pollen easily, and that have open anther cones and extended stigmas.

[JimmyCrackedCorn]

Thanks for the link. I searched a bit but didn't find that other thread.

[Worth1]

Just so as you know, many tomato blooms pollinate before they open.

And I wouldn't believe everything a local extension employee told me.
But I wont get into that other than to say, 'A doctor that graduates last in their class is still called doctor.

Worth

[JimmyCrackedCorn]

Thank you Joseph and Worth1. The consensus here has my trust a lot more than one person, normally, but this guy has an official title. I appreciate your input.

[joseph]

Yesterday I found a natural hybrid in one of my bean varieties. That is rarer than finding a tomato hybrid. I am one delighted farmer about now.

[Tormato]

With this thread, I should check again to see if we have any "mathletes", here at T'ville.

It's estimated the chance of a cross is about 5% (1 in 20).

So, if you saved seed from two tomatoes and grew out one plant from each source, would there be a 1 in 400 chance of both plants being crossed, a 2 in 400 chance, or something else?

Dr. Lve Apple

[Tormato]

Originally Posted by joseph

Yesterday I found a natural hybrid in one of my bean varieties. That is rarer than finding a tomato hybrid. I am one delighted farmer about now.

Joseph,

The estimate on bean crosses is said to be about 0.5% (1 in 200).

With my own saved bean seed, I average about 1 in 275. That's with many varieties planted in a given year and virtually no isolation. There are a few varieties that are said to have a higher rate of crossing. Jeminez is one, and that's a variety that has produced crosses for me.

Gary

[joseph]

Originally Posted by Tormato

It's estimated the chance of a cross is about 5% (1 in 20).

So, if you saved seed from two tomatoes and grew out one plant from each source, would there be a 1 in 400 chance of both plants being crossed, a 2 in 400 chance, or something else?

The chances are 1:400 that both seeds will be crossed.

Thanks Gary: I am cussing myself today, because I wore orange colored sunglasses yesterday when I was harvesting the beans. If I had been wearing a different pair of sunglasses I would have noticed the cross immediately instead of only finding it after I was done picking, threshing, and winnowing.

My peas have about a 1:200 cross pollination rate (as far as I can discern based on phenotype changes.)

I don't have a good way to measure (or even notice) cross pollination rates with my beans, but this particular cross jumped out at me because the offspring changed color. 13% of the beans harvested were off-type, so this might be a segregating F2/F3 from a previous growing season. 4% of the beans were reversals which is typical for this variety.

[Doug9345]

It's really some other number. The 5% says that 1 in 20 VARIETIES will have at least 1 seed that is not true to type. They number says nothing about what percentage of seeds in each tomato that has crossed seed in it are crossed and how many are not. The 5% also says that you have condition (pollinator) that are working tomato plants.

With all that said I believe the bigger the number of seeds you save, the less the percentage of seeds that are going to be crossed. Bee's tend work flowers that are near them and not fly randomly from plant to plant. When they fly from plant A to a plant of a different variety they are or can be bearing a lot of pollen, but as they work from one flower to the next it would seem to me that they would leave much more pollen from the other variety on the first flower they visit than the last.

What I would like to know is when I have a crossed tomato what percentage of the SEED is crossed in THAT tomato. That would tell me more about what kind of problem I have

[Lee]

Said it before, and I'll say it again.... no bees = 0% chance of cross pollination.

If you've got bees, then it can be 0% to 100%.... all depends on your
location, variety type, and the bee activity. 5% is an anecdotal number based on long term observation, but by no means should be considered the rule.

Lee

[joseph]

Originally Posted by Doug9345

It's really some other number. The 5% says that 1 in 20 VARIETIES will have at least 1 seed that is not true to type. They number says nothing about what percentage of seeds in each tomato that has crossed seed in it are crossed and how many are not.

If there are 100 seeds in a tomato fruit, and I have one fruit from 20 different varieties, then that is 2000 tomato seeds. If only (at least) one seed is required to be crossed then that is a only 0.05% chance of cross pollination... 2 orders of magnitude different than the anecdotal experience that on average if you plant 20 open pollinated tomato seeds that one of the seeds will be off type. That's just the most typical average that people can expect.

[Tormato]

Originally Posted by Lee

Said it before, and I'll say it again.... no bees = 0% chance of cross pollination.

If you've got bees, then it can be 0% to 100%.... all depends on your
location, variety type, and the bee activity. 5% is an anecdotal number based on long term observation, but by no means should be considered the rule.

Lee

Got ants? I have them constantly crawling all over my tomato and bean flowers. My guess is that they do some of the crossing, maybe even more than the bees, in my garden.

Gary