Hybrid seeds are great for the season that you plant them. After that you don’t know what you will get if that plant re-seeds itself. For instance, I used to buy seeds for the hybrid cherry tomato called Sweet 100. It grew amazingly sweet cherry tomatoes and lots of them. I got many, the birds got some too, and the next season I had baby tomato plants coming up all over my property from the seeds the birds had spread. They were cherry tomatoes, and they were tasteless. That is the primary problem with growing hybrids. It is possible to get a good plant from the seed of an hybrid, but it is a crap shoot. It could go either way. Now if you did get a good seed from a hybrid and were able to keep saving seeds from its progeny, and you got the same good crop over and over again you could say your hybrid reverted to an earlier desirable strain of plant and it has therefore become an heirloom plant. Heirloom plants come true to seed.

These days I grow only heirloom tomatoes, and I only eat heirloom tomatoes. This ensures that what comes up as a volunteer in my garden will be worth the space in which it grows. I have found that the tomatoes that volunteer on my property do better than the tomatoes I plant myself. They thrive in the location in which they germinated, and do this without any special tending by me.

Another word for heirloom is “open pollinated”. An heirloom or open pollinated plant is not static. Where ever it grows the plant learns about its environment, and passes this information to the seed. This is a type of evolution, or you could call it a genetic memory.
This is why when we save seeds we save from the strongest and most delicious fruiting plants and we save the best bean or tomato seeds from that super strong and healthy plant. We are hoping to develop the best tasting and strongest plants for our particular environment.

Genetically Modified Organisms or GMO’s are a whole other creation. These seeds have had their genes actually spliced to change the plant. They do this to make plants immune to a widely used herbicide so that it can be sprayed nearby without killing the GMO plant. They also splice genes to make plants toxic to pest insects that normally chew on that plant. These are very bad practices and have created unexpected anomalous results such as insects that are immune to the built in pesticide (super bugs they are calling them), and because of cross pollination, weeds and nearby plants that are now immune to the popular herbicide round up. To date there are no laws that require food producers to label their products that contain GMOs. I am hoping that will soon change. GMO seeds, plants and foods from them are banned in many other countries.

I hope this helps you to better understand the difference between Heirloom or Open Pollinated and Hybridized seeds, and GMOs

You say not to save hybrid seeds because they revert back to the negative properties of the parents or they will be sterile and not germinate.

Later you say that you plant your strains for several seasons and you can name it when it gets proven.

Both of those statements make sense to me in their own right. However, what is the difference between hybrid and strain in these contexts? They seem to me to be saying contradictory things.