Today, seeds are generally bred in one of three ways: 1) in an open pollinated environment, 2) through a hybrid cross, and 3) through genetic modification. Here at Southern Exposure Seeds Exchange, we specialize in open pollinated seeds.
Open pollinated seed saving is the oldest of the three methods, in all likelihood predating agriculture itself. All heirloom seeds are open pollinated. When a breeder raises a population of open pollinated plants that are of a like variety and keeps pollen from other varieties from entering the patch (generally accomplished with just distance from another variety), she or he will have the ability to save open pollinated seeds from the patch. If the best two thirds of the patch is used for the seed crop, the variety will generally hold it's quality through the generations. If only the best half or fewer plants are saved for seed, the variety will generally improve.
Hybridization, on the other hand, is when some technical method is applied to two open pollinated varieties growing side by side to ensure that every seed has received pollen from one breed (the father) and is grown on a distinctly different breed (the mother). This is done in many methods, the most commonly know being corn detasseling. In this method, three rows of the father breed are planted, and then one of the mother, and over and over. The mother rows are detasseled (had their pollen removed) ensuring that any pollen they receive came from the father rows. The mother's seeds can then be harvested as what is known as an F1 (first generation) hybrid. If the offspring of the F1 hybrid were all grown as an open pollinated variety and the seed saved, that would then be the F2 hybrid generation, and so on.
In order to understand why this is important to us at Southern Exposure Seed Exchange, it is important to understand what the genetic ramifications of these two methods are. There are many many genes occurring in pairs on the chromosomes of every living organism. Of all those organisms that were sexually reproduced (including both discussed methods above), one of every pair of genes is received from the mother and the other from the father.
These genes pairing off on their chromosomes have all the preset genetic material to make the organism what it is. If the genes were different, the organism would look and act differently. In a hybridized variety, the two parents would each have different genes.
Different genes opposite each other on a chromosome are often represented by different capitalization of a letter. For example, if I were growing an open pollinated tomato that had a characteristic that was consistent, I could say that the gene controlling that characteristic would be represented by the G gene. As all of the mother and father plants share this characteristic, all of the plants in the patch would then have a GG for the matching pair of genes. Now if I had another variety of open pollinated tomato that had a different gene in that spot, I could say that variety has a gg in the same spot on the chromosome.
Now when I hybridize the two varieties to get the F1 generation, I can say they will all have a Gg in this spot, as they got one gene from the GG mother and one gene from the gg Father.
Now say we were to look at the F2 generation. Well, there are four possibilities. Either the seeds will get a G from the father and a G from the mother, a G from the father and a g from the mother, a g from the father and a G from the mother, or a g from the father and a g from the mother. Therefore, half of the plants will be Gg, a quarter will be gg, and a quarter will be GG.
Now say that there were a thousand different genes that were different between the original mother and father. Multiply the thousand by the three possibilities and you see you have the possibility for 3000 distinct varieties to emerge in the F2 generation.
Therefore, if you grow out an open pollinated variety and save it for seed, you will get offspring that are similar to the parents. On the other hand, if you purchase an F1 hybrid seed and you save it for seed and attempt to grow it for seed, the F2 generation will be a very random mix and will not serve any consistent need, as all the plants will be wildly different.
So if you grow an open pollinated variety and you like it, you can save it and adapt it for your area and enjoy the full pleasure of taking the plants through their entire life cycles as they produce for you from generation to generation. If you grow an F1 hybrid seed and you like it, you must go back to the source you purchased it from if you wish to grow it out again.
We believe that for this reason, it is important to sell open pollinated seeds. Over 98% of our seeds are open pollinated, the hybrids being clearly marked online and in our catalog.
The third type of seed breeding is genetic modification. It involves, through laboratory means, taking a seed from one species and implanting it into another species where it would have never naturally occurred. At Southern Exposure Seed Exchange, we have a host of concerns with this breeding technique.