For any community self reliance project to work, it will need a diverse supply of sustainable seeds in order to grow that which is will use as community resources. Having a supply of 
seeds that can constantly be worked back into your system year after year is a sure fire way to ensure resilience. The best type of seeds to supply you with an ongoing saveable supply are open cultivar seeds, commonly known as Heirloom here in the UK, and Heritage seeds in the US. These open cultivar seeds allow us to let some of our crops go to seed so that we have a supply for the following years crops or produce. This type of seeds will also give your community group a level of independence in terms of having a secure self perpetuating seed stock which will allow for seasonal growing regardless of whatever is happening to the controlled seed Markets outside of your project, this isn’t to say that you wont have to introduce newer varieties from time to time over the long term.
Seed diversity and independence
In order to keep your system running perpetually and smoothly it is advisable to have a very diverse supply of seeds that serve different purposes, some of your seeds will be used to grow and produce food, some for green manure, some for attracting wildlife, and some for soil fertility etc. It would also make sense to have diversity within single fruit and vegetable types, this serves a few good purposes, it means that you are able to grow produce that has different attributes such as taste, texture, storage ability and nutrition, having this diversity within certain types of produce also means that new varieties can be created, which in turn will also have certain attributes that are perhaps more suited to the specific climate where they are growing.
Steve