How easy is it to get a bee cross?

[attml]

This may sound like a stupid question, but how easy is it have a bee cross between varieties? I have about 50 different tomatoes this year and about 10 more that are duplicates of my favorites. I was in the yard yesterday morning and I watched a single bee go flower to flower (variety to variety) on just about every plant I had. I was extremely happy that I was getting the pollenation but was wondering if this automatically means cross-pollenation? Thanks!

Mark

[carolyn137]

Originally Posted by attml

This may sound like a stupid question, but how easy is it have a bee cross between varieties? I have about 50 different tomatoes this year and about 10 more that are duplicates of my favorites. I was in the yard yesterday morning and I watched a single bee go flower to flower (variety to variety) on just about every plant I had. I was extremely happy that I was getting the pollenation but was wondering if this automatically means cross-pollenation? Thanks!

Mark

http://faq.gardenweb.com/faq/lists/t...852004159.html

Above is an excellet FAQ from GW on how to prevent cross pollination which I think will help.

Seeing bees, the most common ones are the halictid sweat bees that are so tiny you seldom see them, but honey and bubmbles can also do it, does not automatically mean that X pollination has occurred since it takes, usually, several bee visits to a blossom to have enough pollen to fertilize the ovules in the tomato ovary.

And most blossoms are self pollenized in the bud stage as the bud develops, so that's another factor as well.

Carolyn

[attml]

Thanks Carolyn!

This looked like a bumble or carpenter bee but had orangish things on it's legs. It did come back to the same flowers on a couple of plants after visiting other varieties so I guess we will see what happens? I don't trade seeds so I am not too concerned about keeping them pure. I was just wondering after watching the little critter working hard.

I am glad to see you back on the board and I hope your health keeps improving! I don't post much but I do lurk on the board and I always enjoy your informative posts and insight!!

Take care!!

Mark

[joseph]

The natural cross pollination rate of tomatoes varies widely depending on what cultivar it is, and what pollinators are present, and how closely different varieties are planted together, and other factors. It is generally considered to be in the range of 1% to 9%. I use a rate of 5% as my working estimate when contemplating how many plants I need to plant in order to have a good chance of finding a natural hybrid.

I culture tomato pollinating insects, and grow plants that attract pollinators near the tomato patch. Anything to help increase the natural cross pollination rate.

[WVTomatoMan]

Several years ago Jeff McCormack did a study and wrote a paper about isolation distances regarding tomatoes. As a by product he determined that cross pollination occurs about 2% to 5% of the time when tomatoes are planted closely together. I think that is a fairly good general approximation and matches what I've experienced in my garden.

There are several factors which can contribute to cross pollination. These inlcude, but are not limited to, flower formation (long styles/exerted stigmas are more susceptible to cross pollination) and the type of bee (sweat bees are more likely to be cross pollinators than bumble bees).

Just because you saw a bee go to several flowers on several plants doesn't mean that cross pollination occured. Generally pollination has happened by the time the flower opens.

Randy

[TZ-OH6]

http://tomatoville.com/showthread.php?t=9251

[carolyn137]

Originally Posted by WVTomatoMan

Several years ago Jeff McCormack did a study and wrote a paper about isolation distances regarding tomatoes. As a by product he determined that cross pollination occurs about 2% to 5% of the time when tomatoes are planted closely together. I think that is a fairly good general approximation and matches what I've experienced in my garden.

There are several factors which can contribute to cross pollination. These inlcude, but are not limited to, flower formation (long styles/exerted stigmas are more susceptible to cross pollination) and the type of bee (sweat bees are more likely to be cross pollinators than bumble bees).

Just because you saw a bee go to several flowers on several plants doesn't mean that cross pollination occured. Generally pollination has happened by the time the flower opens.

Randy

Randy, the article that Jeff wrote is still available at SESE and it's an excellent article about all the variables that go into NCP ( natural cross pollination).

I've linked to that article here many times, but don't have the time to do so right now.

it's an excellent article for those interested and you have to remember that at the time Jeff owned SESE so his suggested distances are very conservative since he was selling seeds. Too conservative for me.

I used to putmyplants in 250 ft rows, 3-4 ft apart and 5 ft between rows and my X pollination was about 5 % which means on average that of seed saved from 100 varieties that on average about 5 will be crossed.

of the many many hundreds I use to SSE list I can remember less than 10 that were cross pollinated.

But depending on all the variables discussed in Jeff's article, crossing rates up to 35-50% are possible.

Carolyn

[MrBig46]

Czech firms, which shop seeds (Moravoseed, SevaSeed, SEMO), must keep isolation distances (it is control by ÚKZUZ):
tomatoes, peppers and eggplants- 100 m
cucumbers, squashes and melons - 1000 m
Mr Big

[dice]

I have not seen one bee yet this spring, but looking at the tomato
flowers, I can tell that they have been there (ends of anther cones
are all chewed up).

[MrBig46]

I use these bags welded from non woven textile.
Vladimír

[RebelRidin]

Originally Posted by attml

How easy is it to get a bee cross?

Just swat at him a few times. That should do it


(Sorry.... It was just kind of hanging there...)

[carolyn137]

I mentioned the article written by Jeff
McCormack above but no one seems interested in fetching it. So between wicked T storms I did b'c I think it's a must read.

http://www.southernexposure.com/isol...es-ezp-35.html

Again, please remember that Jeff owned SESE so was commercial thus his isolation distances are very conservative. And I gave some data above on what my crossing rate was and how far apart I used to grow my tomatoes.

Hope the above link helps,

Carolyn

[Salsacharley]

Originally Posted by carolyn137

I mentioned the article written by Jeff
McCormack above but no one seems interested in fetching it. So between wicked T storms I did b'c I think it's a must read.

http://www.southernexposure.com/isol...es-ezp-35.html

Again, please remember that Jeff owned SESE so was commercial thus his isolation distances are very conservative. And I gave some data above on what my crossing rate was and how far apart I used to grow my tomatoes.

Hope the above link helps,

Carolyn

Thanks for that link.

I wonder if using the toothbrush pollinating method can increase cross pollination between plants. I have plants pruned to 2 stems vertically, and spaced about 2 ft apart, and I use the toothbrush to enhance pollination which appears to be working. However, sometimes with the toothbrush stimulation I see pollen spewing out of a flower at an amazing volume into the general garden.

Charley

[carolyn137]

Originally Posted by Salsacharley

Thanks for that link.

I wonder if using the toothbrush pollinating method can increase cross pollination between plants. I have plants pruned to 2 stems vertically, and spaced about 2 ft apart, and I use the toothbrush to enhance pollination which appears to be working. However, sometimes with the toothbrush stimulation I see pollen spewing out of a flower at an amazing volume into the general garden.

Charley

Charley, when you say to increase pollination between plants, I assume different varieties,does that mean you actually want to increase cross pollination? That's the way I read it.

Carolyn

[dice]

Originally Posted by Salsacharley

I wonder if using the toothbrush pollinating method can increase cross pollination between plants.

It could if you were growing a lot of plants with
"exerted stigmas", like Joseph. This picture of a flower on
Gillogly Pink from TOMATObase shows what an exerted
stigma looks like:
http://tatianastomatobase.com/w/imag...nk_Flower2.jpg

Wind could pick up pollen vibrated out of a flower and carry
it to other flowers on nearby plants of other varieties.

There are plenty of exerted stigma types among heirlooms, and
some author named Gopalakrishnan in a 2007 book said that hot
weather increases the tendency for tomato flowers to have
exterted stigmas.

Most growers have few plants like that, though. This
Beauty King flower does not look so much exerted stigma
as simply bee-chewed, where a bee grabbed ahold of
the end of the anther cone and then did his vibrating thing
to shake out the pollen:
http://tatianastomatobase.com/w/imag...ng_Flower_.JPG

These Break O' Day flowers are the kind that I see the most:
http://tatianastomatobase.com/w/imag...ay_Flower2.jpg
They are not likely to cross-pollenate, unless a bee with a belly
covered with pollen from something else opens up the end of
the anther cone before the flower has self-pollenated and gets
pollen from another cultivar all over the pistil.

Figure that any flowers that bees have opened up are probably
already pollenated, so pollen wind drift from your vibrating
device will not affect those. Once a flower has some color
besides green, there is a good chance that it already
self-pollenated.