Thread: hybrid seeds
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Old June 14, 2009   #2
nctomatoman
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Hi, Tom - Your words, then some comments.

"we know that hybrid tomato seeds will not reliability produce the same hybrid tomato they came from. but i suspect there is 1 or 2 generations that do. since i don't understand genetics, please speak to a lay person."

Seed saved from hybrids may or may not look like the parent, and may or may not in 1 or 2...or even 5 or more generations. It depends upon the "wideness" and complexity of the cross (crossing two very similar or two very different tomatoes).

"so we take tomatoes a and b (i have read there may be several parents involved in a hybrid not just 2 parents) and produce tomato seeds for sale to the public. so when you cross tomato a flowers with tomato b pollen you grow tomatoes and let's call the seeds in those tomatoes generation I.

it seems that they have to grow generation I seeds to ensure that the tomato is what they want, if i buy sun gold or jet star i do not want sweet 100 or big mama. so they grow generation I, it's what they want and then they harvest the seeds so that is generation II. we buy generation II and grow our hybrid tomatoes."

When they do the crosses and the tomatoes develop, it is the seeds from those tomatoes that are sold as the hybrid. If you save seeds from those, it is the F2 generation and you can get all sorts of variations. They may do a growout now and then as a quality control step, but it is those seeds from the actual pollination/developed fruit that are the hybrid.

"so there seems to me, if i am correct in my assumptions, that a hybrid is true to type for 1 or 2 generations and i'm guessing that after that they become less stable and start to revert to whatever their parents were.

am i correct or way off base?

if i am wrong then how in the world do they know the hybrid seeds they are selling are what they say they are? and if hybrids are not true to type then how do they produce seeds without growing them to be certain they are what they expect?"

It takes a long time to stabilize on something you want, as we are demonstrating in the Dwarf project. Patrina, Vince, Ray and Bruce have all created the hybrids. They make the crosses and we in the project grow out seeds from the tomatoes that develop from the cross. We save seeds and then get lots of variation in the F2 generation. We pick out an F2 we like, save seeds from it, and grow out as many as we can, because there continues to be lots of variation. It can take up to 5, 6, 7 generations or more to create a stable new variety - again, depending upon how different the parents were in the first place. Plus, there are quite a few genes responsible for any particular tomato variety - associated with shape, size, skin color, flesh color, flavor, leaf shape, plant type, etc. Certain characteristics are faster to stabilize than others. In the dwarf project, the saved seed from the hybrid produced 25% dwarf plants. But when you grow out those dwarfs, saved seed provides 100% dwarfs from there on (because dwarf is a recessive trait - they tend to be easier to nail down).

Hope that helps! But it does explain the relatively high cost of hybrid seed - you are getting the seed directly from the fruit from the crosses.
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