Cross - pollination: Is it an issue?

huntsman · November 21, 2009

I know peppers will cross pollinate very easily. Are 'maters the same?

Do I need to bag some blooms to ensure that the fruit grows 'true' to the variety?

Mine are all in the same area...?

mjc · November 21, 2009

Chances are lower, but to ensure purity, bag them...

TZ-OH6 · November 21, 2009

In my garden cross pollination is an issue (0-40% of seeds per fruit--- average = around 20% of seed from mid-late season flowers) so I bag, and just in case a bag doesn't produce fruit I also save seeds from the first fruits of the season when cross pollination is much lower here.

Determining amount of cross polination in your own garden is easy, just plant 50 or so seeds (in a single pot) from each of several potato leaf variety fruits and see what the proportion of regular leaf seedlings appear to get the rate of cross polination from regular leaf plants. And then factor in the ratio of regular leaf to potato leaf varieties you are growing to determine the amount of probable cross pollination from different potato leaf varieties to get your total estimate of cross pollination.

I find that I have higher success by bagging the first or second flower truss of the year. Later in the season I sometimes have trouble getting fruits to develop in the bags.

mvan · November 21, 2009

What do you use for bags. I made some from Reemay this year, but they seem to have suffocated the blossoms. I have some extra window screen, and I may try to make some out of that next year.
Any suggestions?

Thanks,
Matt

**carolyn137** · November 21, 2009

For a very complete discussion of cross pollination, how to bag, etc., with pictures, you might want to consider going to Gardenweb.com then go to the Growing Tomatoes Forum, then at the top of the first page click on FAQ's and scroll down to the article on How To Prevent Cross POllination.

I think all of your questions will be answered and if not, just post them here.

I tried Reemay just once and all the blossoms bagged rotted; tulle is much better and is discussed in that GW article. I happen to think it's one of the best articles on X pollination around and that one and several more were done by a cooperative effort of several folks, some of them post here almost exclusively now after Tville was started by Mischka back in 2006.

Forget the FAQ on Tomato varieties b'c it's way out of date.

If you want to post there you have to register but like almost all message sites you can read most Forums without registering and I'm pretty sure you can also read those FAQ's b/c I've sent folka there before for the X pollination one as well as the leaf structure one.

**nctomatoman** · November 21, 2009

I've done studies on my seed saving method to test its general effectiveness. I don't bag blossoms and my plants are quite close together. I have the occasional potato leaf variety in amidst a majority of regular leaf varieties. When I grow out seed saved from potato leaf, by counting the regular leaf seedlings, I can get a ballpark estimate of crossing. Even when not saving seed from first or last set fruit (when bee activity is lowest), I tend to get a maximum of 5% crossing (so find 5 regular leaf seedlings and 95 potato leaf seedlings). When I limit my seed saving to first or last fruit, that number drops down to 1-2%.

So it all depends upon what you are aiming for. If you are trying to preserve a very rare variety and are sharing seeds, and want 100% (or as close to it) chance of pure seed, separation by good distances, planing only one variety, or use of Reemay to bag blossoms is the way to go. If you can live with the fact that, out of 25 seedlings, 1 may be the wrong variety, then you should be fine, though limiting seed saving to first or last set fruit helps that considerably as well.

Blueaussi · November 21, 2009

Tomatoes aren't the garden sluts that peppers are, but cross pollination can happen, as has been pointed out.

I've made my own bags out of tulle, but have found that the paint strainer bags from a big box store are cheap and easy to use. Just don't, as I have ruefully mentioned before, bag a tomato hornworm egg along with your pepper or tomato flowers. Unless you want, you know, a good story to tell on yourself.

huntsman · November 21, 2009

Heh heh heh heh!

I can just picture that happening, Blue!

Great advice as always folks - thank you!

Clearly it's not the same problem that it can be with peppers, but I'm off to GW to learn more all the same...

November 21, 2009	#1
huntsman Tomatovillian™ Join Date: Jul 2009 Location: Johannesburg, South Africa - GrowZone 9 Posts: 595	Cross - pollination: Is it an issue? I know peppers will cross pollinate very easily. Are 'maters the same? Do I need to bag some blooms to ensure that the fruit grows 'true' to the variety? Mine are all in the same area...?

November 21, 2009	#5
carolyn137 Moderator Emeritus Join Date: Jan 2006 Location: Upstate NY, zone 4b/5a Posts: 21,169	For a very complete discussion of cross pollination, how to bag, etc., with pictures, you might want to consider going to Gardenweb.com then go to the Growing Tomatoes Forum, then at the top of the first page click on FAQ's and scroll down to the article on How To Prevent Cross POllination. I think all of your questions will be answered and if not, just post them here. I tried Reemay just once and all the blossoms bagged rotted; tulle is much better and is discussed in that GW article. I happen to think it's one of the best articles on X pollination around and that one and several more were done by a cooperative effort of several folks, some of them post here almost exclusively now after Tville was started by Mischka back in 2006. Forget the FAQ on Tomato varieties b'c it's way out of date. If you want to post there you have to register but like almost all message sites you can read most Forums without registering and I'm pretty sure you can also read those FAQ's b/c I've sent folka there before for the X pollination one as well as the leaf structure one. __________________ Carolyn

November 21, 2009	#6
nctomatoman Tomatoville® Moderator Join Date: Jan 2006 Location: Hendersonville, NC zone 7 Posts: 10,385	I've done studies on my seed saving method to test its general effectiveness. I don't bag blossoms and my plants are quite close together. I have the occasional potato leaf variety in amidst a majority of regular leaf varieties. When I grow out seed saved from potato leaf, by counting the regular leaf seedlings, I can get a ballpark estimate of crossing. Even when not saving seed from first or last set fruit (when bee activity is lowest), I tend to get a maximum of 5% crossing (so find 5 regular leaf seedlings and 95 potato leaf seedlings). When I limit my seed saving to first or last fruit, that number drops down to 1-2%. So it all depends upon what you are aiming for. If you are trying to preserve a very rare variety and are sharing seeds, and want 100% (or as close to it) chance of pure seed, separation by good distances, planing only one variety, or use of Reemay to bag blossoms is the way to go. If you can live with the fact that, out of 25 seedlings, 1 may be the wrong variety, then you should be fine, though limiting seed saving to first or last set fruit helps that considerably as well. __________________ Craig

November 21, 2009	#2
mjc Tomatovillian™ Join Date: Jun 2009 Location: WV Posts: 603	Chances are lower, but to ensure purity, bag them...

November 21, 2009	#3
TZ-OH6 Tomatovillian™ Join Date: Feb 2008 Location: Mid-Ohio Posts: 848	In my garden cross pollination is an issue (0-40% of seeds per fruit--- average = around 20% of seed from mid-late season flowers) so I bag, and just in case a bag doesn't produce fruit I also save seeds from the first fruits of the season when cross pollination is much lower here. Determining amount of cross polination in your own garden is easy, just plant 50 or so seeds (in a single pot) from each of several potato leaf variety fruits and see what the proportion of regular leaf seedlings appear to get the rate of cross polination from regular leaf plants. And then factor in the ratio of regular leaf to potato leaf varieties you are growing to determine the amount of probable cross pollination from different potato leaf varieties to get your total estimate of cross pollination. I find that I have higher success by bagging the first or second flower truss of the year. Later in the season I sometimes have trouble getting fruits to develop in the bags.

November 21, 2009	#4
mvan Tomatovillian™ Join Date: Feb 2009 Location: Fairburn, GA z7 Posts: 72	What do you use for bags. I made some from Reemay this year, but they seem to have suffocated the blossoms. I have some extra window screen, and I may try to make some out of that next year. Any suggestions? Thanks, Matt

November 21, 2009	#7
Blueaussi Tomatovillian™ Join Date: Apr 2009 Location: South Carolina Zone 8a Posts: 1,205	Tomatoes aren't the garden sluts that peppers are, but cross pollination can happen, as has been pointed out. I've made my own bags out of tulle, but have found that the paint strainer bags from a big box store are cheap and easy to use. Just don't, as I have ruefully mentioned before, bag a tomato hornworm egg along with your pepper or tomato flowers. Unless you want, you know, a good story to tell on yourself.