This post is simply a follow up from the last post.
I think confusion over cross-pollination and inbreeding depression are what lead most people to give up on seed saving, but it’s really not a difficult concept! It really comes down to what Real Seeds say in their seed saving guide:
Do your plants breed in groups?
If yes, then you need to make sure the group is large enough and distinct groups are isolated from one another (these two concepts always go together). If no, than you have a lot less to worry about when you save seeds.
If your plants breed in groups, then they are referred to as outbreeding plants. Somehow the pollen from one plant travels to nearby plants, usually by way of insects or the wind. Plants that breed in groups are genetically predisposed to needing a large gene pool to stay healthy.
If your plants do not breed in groups, they are referred to as inbreeding plants. Inbreeding plants usually have entirely self-contained flowers with both male and female elements, the pollen doesn’t leave the plant and they pollinate themselves. These kinds of plants are genetically predisposed to being tolerant of a small gene pool.
The only slightly confusing part of all of this is that nature is not usually so kind as to give us something black and white, and there are lots of in between situations. Plants are usually referred to as mostly inbreeding or mostly outbreeding.
Inbreeding Depression
If you save seeds from plants that breed in groups, with too small of a group, you will eventually have problems with inbreeding depression. This can result in plants that are no longer suitable for growing, but it often takes a number of generations for these problems to emerge.
This can be fine if you’re only saving seeds for your self, and only intend to grow them for a couple of generations. On the other hand, this can be a serious problem if you share the seeds with someone else who is unaware of the problem.
Plants that do not breed in groups do not develop this problem as easily, but it’s always a good idea to save seeds from a couple of plants to help avoid the problem.
Start with inbreeding plants
When you begin seed saving, you should start with plants that are nearly or totally inbreeding and therefore do not need to breed in a group with nearby plants and do not often accidentily cross pollinate with others.
Popular examples of this are tomatoes, beans and peas.
Inbreeding depression is due to the random loss of genes in a population which is too small. One possible anwer might be to have a group of people working together on a project, and pooling seed at the end of the season. The seed would then be mixed together, and returned to the contributors for the next season.
Definitely! There are a few ongoing group breeding and seed saving projects ongoing. Our host Alan of the HG discussion forum is working on sweet corn. There is a perennial grain project being worked on by Tim Peters on the HG forum. There are others but I don’t know if they are open to everyone, you need to make contact with the people organizing them and see if they want someone to participate.
This is not just with respect to inbreeding depression, but also adaptation to different climates.