put a small plastic or paper bag over the blossums before they open secured with a twistey when the blossoms open use a different artists brush for each crossbreed to take the pollen from one and put it in another. after pollinating replace a twistey and bag until blossom drops off and fruit is set ( to prevent unwanted and unknow crossbreeds) then label the tomatoe and wait till it gets over ripe and falls from the vine if you can .

Tomatoes are a self pollinating crop, thus emasculation is important.
The anthers need to be removed before the flower has opened, otherwise it would be too late. When the flower starts to swell (2-3 days before opening) you should open it with a set of tweezers - being careful not to damage the style.
The removal of the calyx, carolla and anthers with the tweezers leaves only the ovary, style and stigma.
Wait two days - then take the anthers from the pollen parent and brush their insides lightly onto the stigma of the female.
Mark your crosses and keep book of them.
The removed calyx leaves provides a way to keep track of hybridizations.
Because there is virtually no cross pollination in tomatoes - it is not needed to be closed.

Hope you kave success!

S.A.Veg

The researchers at the Beltsville MD center were doing a lot on potatoes (another solanacaea) a few years back , and also on turnip-radish hybrids. Hardest thing on the inter variety crosses is the carefull emasculation of the flower that is going to be the seed parent to prevent self fertilization. One generally disects the flower BEFORE it opens to remove all anthers, then bags it till it is ready to pollinate.

George

here's a link to a University site with a detailed protocol on tomato breeding. scroll all the way to the bottom and you'll see -- in pictures -- how to emasculate and cross-pollinate.

http://www.hcs.ohio-state.edu/hcs200/BreeLab.html

have fun!

I have a question regarding the following scenario. If I emasculated a tomato blossom before self-pollination could naturally occur, and gathered pollen in a shot glass from several different tomato varieties (different colours & shapes) all mixed together with a brush, and then used this mixed pollen to pollinate, would this one tomato give off a whole range of potential crosses with all those different varieties from the individual seeds of this one tomato?

Patrina

Patrina,
Yes.
If you pollinate "Golden Jubilee" with a mixture of pollen from "Yellow Pear" and "Roma". Some of the seeds would grow plants of the hybrid "Golden Jubilee" X "Yellow Pear", and some would grow plants of the hybrid "Golden Jubilee" X "Roma". Each seed would have only one pollen parent but it could be either of the two used. In this case, the fruit color of these offspring hybrids would allow you to distinguish between them.
To complicate matters when using mixed pollen, some pollen grains will grow faster than others. This "pollen competition" could result in one pollen parent having an advantage. The majority of the seeds would then come from the more competitive of the two (or more) pollen parents.
Many hybridizer's often use mixed pollen hybridizations when they aren't very concerned with exact parentage. In my opinion, you can use this strategy to lower the number of unproductive crosses (less chance of incompatibilities being a problem) and to maximize percentage of vigorous offspring (since the most vigorously growing pollen tubes will win the race to the ovules). Have fun and let us know how things turn out. Tom

Tom, thanks for the info. I figured that it was possible from looking closely at the stigma and style area in closeup pics of tomato flowers. Not sure if I will try it or not, but it would be fun if I had enough room to grow out all the seeds of that tomato! As it is I don't have enough room to grow out all the different heirloom varieties I want to taste : ) If the mood and inclination strikes at the right time, I might try it anyhow!

Patrina