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Creating a better heirloom vs. creating a hybrid
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Posted by TheTick z5 Iowa (My Page) on Sat, Oct 15, 05 at 6:30
| I am giving a seed-saving demonstration and I want to be sure I have my facts straight about open-pollinated and hybrid plants. I have just started learning about hybridization. Can you please tell me if the example below is accurate and, if not, what should be changed to make it more accurate?
Many thanks!
This is the simplistic example I plan to present…
If I want to create a better heirloom Brandywine tomato for my region (and my taste), I ensure the plant pollinates itself and save the seeds from fruit that have characteristics I favor. The resulting plant is said to be "open-pollinated" (which seems to be a misnomer since I had to ensure it was not pollinated by another variety of tomato).
If I want a different type of Brandywine, say a fruit that is more like a roma, I would pollinate the Brandywine with the pollen from my favorite heirloom roma tomato, like Martino’s Roma. I would save seeds from fruit that have characteristics I favor – namely a roma-like Brandywine. Planting these seeds would result in a "F1 hybrid" plant; meaning it is the first generation (a filial) that resulted from crossing two pure parents. If I plant the seeds from these F1 Brandy-Roma fruits, the resulting plants will likely resemble either the Brandywine or the Martino’s Roma. These plants are "F2 hybrids".
If I want to stabilize the Brandy-Roma and try to grow the plant without having to cross the parents each time, I would plant the seeds from the F2 Brandy-Roma and ensure that the resulting plants pollinate themselves. I would save the seeds from fruit that have characteristics I favor – namely a roma-like Brandywine. I would repeat this planting, self-pollinating, and seed-saving process until all the plants in a single generation consistently produce favorable roma-like Brandywine fruits. At this point it can be said I have created a new "open-pollinated" variety. |
Follow-Up Postings:
RE: Creating a better heirloom vs. creating a hybrid
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| I have made changes to the statements to better represent the situation. Tomato is unusual in that its normal method of pollination is often self-pollination. The changes are in bold. Open-pollinated means the plant is pollinated naturally by whatever means is normal (insects, wind, birds, etc). If I want to create a better heirloom Brandywine tomato for my region (and my taste), I ensure the plant pollinates itself and save the seeds from plants that have fruit that have characteristics I favor. The resulting plant is said to be "self-pollinated" or an inbred line If I want a different type of Brandywine, say a fruit that is more like a roma, I would pollinate the Brandywine with the pollen from my favorite heirloom roma tomato, like Martino’s Roma. I would save seeds from plants that have fruit that have characteristics I favor – namely a roma-like Brandywine. Planting these seeds would result in a "F1 hybrid" plant; meaning it is the first generation (a filial) that resulted from crossing two pure parents. If I plant the seeds from these F1 Brandy-Roma fruits, the resulting plants will likely resemble neither the Brandywine nor the Martino’s Roma but be a variable mix of both. A very few may look similar to the parents.These plants are "F2 hybrids". If I want to stabilize the Brandy-Roma and try to grow the plant without having to cross the parents each time, I would plant the seeds from the F2 Brandy-Roma and ensure that the resulting plants pollinate themselves. I would save the seeds from plants that have fruit that have characteristics I favor – namely a roma-like Brandywine. I would repeat this planting, self-pollinating, and seed-saving process until all the plants in a single generation consistently produce favorable roma-like Brandywine fruits. At this point it can be said I have created a new inbred line. Because tomato self-pollinates frequently your inbred line would be able to exist as an open-pollinated variety after its characteristics had been 'fixed' or made homozygous. |
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