The importance of using adapted seeds

I’m working on a  food forest project in The Amazon jungle and I’m dealing with a client who insists on using moringa seeds from any source and also anona muricata seeds ( here they can grow in deserts but also i'm the jungle) , downplaying the importance of selecting seeds adapted to the local conditions. From my experience, I know that non-adapted seeds can grow stressed, affect their development, and even negatively impact nearby plants. How crucial do you consider it to choose seeds adapted to local conditions, even for species that are seemingly resilient like moringa?
Do You think it crucial to plant a seed that comes from The same environment ?

If yes. How would You convince to a normal person?

I’m not sure about convincing, but I agree with you and think that after a while their experiences will show them how to do things. People will get very fixated on things and ignore or reject any advice to the contrary. If you tell them what you think without being annoying or appearing as if you are trying to convince them, eventually they might see this reflected in their experience and remember your advice.

I know I could say that I can rarely get seeds to grow at all that are not local, most of the time. If one or two grow out of a packet of fifty, it’s cause for celebration. I still try now and then and sometimes there’s some success. But it always takes a few generations for them to adapt.

From any source?

To me that implies more than one. I'd agree with them and encourage them to find any and every available source. Then landrace them and let them select themselves and ultimately develop into a fully adapted local variety.

The agreeing with them gets them working with you rather than against you. Then when they lose track of which seeds do well and which ones just keel over and die they will still think they did the right thing and everyone is happy.

I believe if buying seeds the best results would be from seeds grown in my area.

We have a seed company where we went in person to buy their seeds and some of the seeds are grown right their on their own property.

How does a person know where the seeds are grown?  

I am sure that company sells seeds that were not grown on their property.  So do we ask where was this particular seed was grown?

Ronaldo said, How would You convince to a normal person?

I have been trying to convince normal people all my life without success.  All I know to do is to tell them how I feel and accept how they live their life (or how they buy their seeds).

Ronaldo Montoya wrote:Do You think it crucial to plant a seed that comes from The same environment ?

If yes. How would You convince to a normal person?

I'm in broad agreement with you, that using locally adapted seeds will result in a more successful plant. My experience indicates that this is more important for some species than others. For example some of my hazel trees have done pretty poorly, disliking the salt winds; the local hazel grows in general better. The rowan trees that are brought in seem to leaf out and flower earlier, and get caught by the cold winds we have in April. However I have been surprise by how well Holm oak, which is a mediterranean tree, has grown here, and Monkey puzzle trees from South America (albeit grown now from seed from UK trees) also thrives.
In terms of risk, I would propose that the longer the life expectancy of the plant and the more expensive and rare the seed the more important local sourcing becomes. If you're prepared to wait a couple of generations, then the population will be adapted - much easier for annual vegetables than a tree that doesn't produce fruit perhaps for 30 years.