Cross pollination of tomatoes (by hand)

Mark0820 · January 10, 2011

I was reading over the weekend about cross pollinating tomatoes (by hand), and the article indicated a F1 hybrid is USUALLY very similar whether variety A is used as the male/variety B as the female or whether variety B is used as the male/variety A as the female. Here is the exact wording:

“Which plant one chooses for a male and which for the female often has little consequence for what most of us are trying to achieve. [IE Stupice x Brandywine vs Brandywine x Stupice (called a reciprocal cross)]. There is what is called the maternal effect. This is the result of DNA present in the chloroplasts of the mother plant (called cDNA). Cholorplasts from the mother plant are transferred to the developing embryo via the ovary. Embryos do not receive cDNA from the male. This can be utilized by plant breeders but most of us would not be aware of such differences and reciprocal crosses to make F1 hybrids USUALLY are fairly similar. If you have time/room, try both.”

So now I am curious. What plant characteristics are impacted by the maternal effect (in general, not detailed technical terms)?

Before reading this article, I never really thought about tomatoes being self pollinated. I have hand pollinated (not cross pollination) squash, pumpkin and melons, but didn’t stop to think that tomatoes are pollinated in a slightly different way. Now that I understand the process, it seems like the chance a tomato cross pollinates (by nature, not by hand) is a fairly low percentage. Clearly, pollen from its own anther cone is more likely to reach the stigma than pollen from another tomato plant. If I think of bee activity in my own garden, the most activity is centered around cucumbers, followed by beans / peppers, with tomatoes at the bottom of the list. I would be more concerned about cross pollination of peppers than tomatoes. These are just my own thoughts, so I am interested in the opinions of other people.

Stepheninky · January 10, 2011

As far as maternal goes I think they are talking about characteristics that would allow you to know that the cross was successful for example if you cross a potato leaf plant (PL) with a regular leafed plant (RL) then the F1 will always be RL as that is the dominate trait. So if the PL plant is the Mother plant and you grow out the seeds and get RL plants then the cross was successful.

Other than that say I was crossing two varieties and one variety produces few seeds or smaller seeds. I would want the mother plant to be the variety that produces more seeds.

Also some varieties are harder to germinate so you would pick the mother plant that has a better germination rate.

Some varieties are harder to cross for example wild types to cultivated types in that case you have a better chance at a cross using the cultivated type as the mother plant.

So to some degree the mother plant could have some effect on the viability of the produced seed.

Anyways thats my guess on it, Maybe one of our breeder members will chime in as well.

**carolyn137** · January 10, 2011

Which plant one chooses for a male and which for the female often has little consequence for what most of us are trying to achieve. [IE Stupice x Brandywine vs Brandywine x Stupice (called a reciprocal cross)]. There is what is called the maternal effect. This is the result of DNA present in the chloroplasts of the mother plant (called cDNA). Cholorplasts from the mother plant are transferred to the developing embryo via the ovary. Embryos do not receive cDNA from the male. This can be utilized by plant breeders but most of us would not be aware of such differences and reciprocal crosses to make F1 hybrids USUALLY are fairly similar. If you have time/room, try both.

*****

Mark, I recognized the above paragraph as you posted being from Keith Muellers online website, which I think is excellent.

http://www.kdcomm.net/%7Etomato/index.html

Did you pursue any of the links in red which Keith gave below the written description, especially the one that said more about breeding tomatoes?

I didn't take the time to do that now, but I wondered if you had in terms of non-reciprocal crosses sometimes being preferred b'c of the maternal cDNA.

Mark0820 · January 10, 2011

Quote:

Originally Posted by carolyn137

Mark, I recognized the above paragraph as you posted being from Keith Muellers online website, which I think is excellent.

http://www.kdcomm.net/%7Etomato/index.html

Did you pursue any of the links in red which Keith gave below the written description, especially the one that said more about breeding tomatoes?

I didn't take the time to do that now, but I wondered if you had in terms of non-reciprocal crosses sometimes being preferred b'c of the maternal cDNA.

I didn't realize this was Keith's website. I didn't see any reference to any name, so I wasn't sure who it belonged to, but the information is very easy to follow.

My Google search took me directly to the "tomato gene basics" page. I see his home page has a lot more information on it than I saw. I read about regular leaf being dominate and potato leaf recessive, so a regular x potato cross will yield a regular leaf. He also explains how the genes of an F1 hybrid population are uniform (using the colored plastic Easter eggs as examples). Then I read about Gene segregation (how genes change from F1 to F2 all the way up to F8).

I haven't read all of the links, so you don't have to do my search for me. I just thought maybe someone at TV might know the answer to my question. If not, that is okay. It is definitely a website I want to spend more time reading. And since you provided the link to the home page, I now know there is even more information than I originally thought.

ireilly · January 14, 2011

Mark, the Univerity of Virginia has a PDF of a paper from 1987 by Donna Roach and Renata Wulff titled "Maternal Effects in Plants."

http://people.virginia.edu/~dar2x/Publications/

Be forewarned I had some issues with Adober Reader 9 being unable to render some pages and that led me down a rathole of looking for reasons for that. But.... you asked for some high-level examples of cytoplasmic DNA effects, and this paper discusses some of that, although it calls for more theoretical work at the end. It is a 23-year-old paper, so perhaps more recent work has been done.

Walter

Mark0820 · January 14, 2011

Quote:

Originally Posted by ireilly

Mark, the Univerity of Virginia has a PDF of a paper from 1987 by Donna Roach and Renata Wulff titled "Maternal Effects in Plants."

http://people.virginia.edu/~dar2x/Publications/

Be forewarned I had some issues with Adober Reader 9 being unable to render some pages and that led me down a rathole of looking for reasons for that. But.... you asked for some high-level examples of cytoplasmic DNA effects, and this paper discusses some of that, although it calls for more theoretical work at the end. It is a 23-year-old paper, so perhaps more recent work has been done.

Walter

Thanks Walter! I'll take a look at it this weekend.

January 10, 2011	#1
Mark0820 Tomatovillian™ Join Date: Oct 2010 Location: Cincinnati Posts: 907	Cross pollination of tomatoes (by hand) I was reading over the weekend about cross pollinating tomatoes (by hand), and the article indicated a F1 hybrid is USUALLY very similar whether variety A is used as the male/variety B as the female or whether variety B is used as the male/variety A as the female. Here is the exact wording: “Which plant one chooses for a male and which for the female often has little consequence for what most of us are trying to achieve. [IE Stupice x Brandywine vs Brandywine x Stupice (called a reciprocal cross)]. There is what is called the maternal effect. This is the result of DNA present in the chloroplasts of the mother plant (called cDNA). Cholorplasts from the mother plant are transferred to the developing embryo via the ovary. Embryos do not receive cDNA from the male. This can be utilized by plant breeders but most of us would not be aware of such differences and reciprocal crosses to make F1 hybrids USUALLY are fairly similar. If you have time/room, try both.” So now I am curious. What plant characteristics are impacted by the maternal effect (in general, not detailed technical terms)? Before reading this article, I never really thought about tomatoes being self pollinated. I have hand pollinated (not cross pollination) squash, pumpkin and melons, but didn’t stop to think that tomatoes are pollinated in a slightly different way. Now that I understand the process, it seems like the chance a tomato cross pollinates (by nature, not by hand) is a fairly low percentage. Clearly, pollen from its own anther cone is more likely to reach the stigma than pollen from another tomato plant. If I think of bee activity in my own garden, the most activity is centered around cucumbers, followed by beans / peppers, with tomatoes at the bottom of the list. I would be more concerned about cross pollination of peppers than tomatoes. These are just my own thoughts, so I am interested in the opinions of other people.

January 10, 2011	#3
carolyn137 Moderator Emeritus Join Date: Jan 2006 Location: Upstate NY, zone 4b/5a Posts: 21,169	Which plant one chooses for a male and which for the female often has little consequence for what most of us are trying to achieve. [IE Stupice x Brandywine vs Brandywine x Stupice (called a reciprocal cross)]. There is what is called the maternal effect. This is the result of DNA present in the chloroplasts of the mother plant (called cDNA). Cholorplasts from the mother plant are transferred to the developing embryo via the ovary. Embryos do not receive cDNA from the male. This can be utilized by plant breeders but most of us would not be aware of such differences and reciprocal crosses to make F1 hybrids USUALLY are fairly similar. If you have time/room, try both. ***** Mark, I recognized the above paragraph as you posted being from Keith Muellers online website, which I think is excellent. http://www.kdcomm.net/%7Etomato/index.html Did you pursue any of the links in red which Keith gave below the written description, especially the one that said more about breeding tomatoes? I didn't take the time to do that now, but I wondered if you had in terms of non-reciprocal crosses sometimes being preferred b'c of the maternal cDNA. __________________ Carolyn

January 10, 2011	#2
Stepheninky Tomatovillian™ Join Date: Aug 2010 Location: Kentucky Posts: 682	As far as maternal goes I think they are talking about characteristics that would allow you to know that the cross was successful for example if you cross a potato leaf plant (PL) with a regular leafed plant (RL) then the F1 will always be RL as that is the dominate trait. So if the PL plant is the Mother plant and you grow out the seeds and get RL plants then the cross was successful. Other than that say I was crossing two varieties and one variety produces few seeds or smaller seeds. I would want the mother plant to be the variety that produces more seeds. Also some varieties are harder to germinate so you would pick the mother plant that has a better germination rate. Some varieties are harder to cross for example wild types to cultivated types in that case you have a better chance at a cross using the cultivated type as the mother plant. So to some degree the mother plant could have some effect on the viability of the produced seed. Anyways thats my guess on it, Maybe one of our breeder members will chime in as well.

January 14, 2011	#5
ireilly Tomatovillian™ Join Date: May 2010 Location: Dallas Posts: 344	Mark, the Univerity of Virginia has a PDF of a paper from 1987 by Donna Roach and Renata Wulff titled "Maternal Effects in Plants." http://people.virginia.edu/~dar2x/Publications/ Be forewarned I had some issues with Adober Reader 9 being unable to render some pages and that led me down a rathole of looking for reasons for that. But.... you asked for some high-level examples of cytoplasmic DNA effects, and this paper discusses some of that, although it calls for more theoretical work at the end. It is a 23-year-old paper, so perhaps more recent work has been done. Walter