From a purely numeric standpoint, you are right about the 'highest genetic diversity is in wild species'. And from a nature conservation perspective, I am with you. We had some really nice discussions about this in our biodiversity lectures...
And the quality of many tradicional varieties is like 'local' cuisine is frequently 'foods that not e en the people from the next village wanted to eat' 🤣 (to paraphrase Terry Pratchett).
However, I would like to add the following:
There is some inherent value in traditional agrobiodiversity. Modern plant breeding has also some drawbacks. Modern plant breeding is powerful process, capable of integrating very distant genetic material into crops, and thus also greatly increasing genetic diversity. And it's quick. However, the process is out of control if the farming community. And the focus lies usually more on a few specific traits, not a gradual complex adaptation like in decades long heirloom breeding. Thus, the traditional cultivars with their complexity and messiness are not easily replaced.
On the other hand, I have frequently heated discussions with the 'heirlooms are the only solution'-people. I disagree a bit, because since industrial capitalism is wrecking the climate and local climate is not what it waswhen heirloom varieties evolved (you know this of course, I provide the reference for others: https://e360.yale.edu/features/redrawing-the-map-how-the-worlds-climate-zones-are-shifting). A worrying question I have not yet a clear answer is: is the breeding&adaptation rate of heirloom varieties quick enough to keep pace with the climatic shifts that will happen in this century?
A few months ago, on a very cool ethnobotany conference some folks presented their seed bank project safeguarding and reintroducing traditional varieties in northern Catalonia (Spain). I challenged them with the shifting climate zones argument and asked about resilience. But I have to admit that the answer was very convincing to me:
Traditional cultivars are connected to a different way of doing agriculture. Also in a farmer-cultural way. For example, this seed bank project created community and motivated farmer-to-farmer exchanges of knowledge and experience. They improved productivity while decreasing environmental impact. And had exchanges with farmers from Morocco (500km south) who teaches them management techniques for arid climates, much needed in the increasingly scorching summers. The answer ended with "our heirloom seedbank is much more than the seeds. It is a community project".
Therefore, one would hypothesize that farming systems with traditional cultivars *tend* to favour more #agroecology practices, small-scale mosaic landscapes, increasing #biodiversity (especially, when doing the grossly simplified and unfair comparison between #PeasantFarming to industrialised large scale farming with modern varieties that were optimized for high-input farming).
Thus, there are system components on different levels we should not forget in this discussion.
Thank you for your always very informative threads! 🌱