[nkurz]

This is a good question, and I'm struggling to find a clear answer.

The Asian varieties are generally blight resistant and grow in the US, but they aren't as good for nuts or lumber. The European varieties are slightly less susceptible to blight, but are definitely susceptible. There are European/Asian crosses that are more resistant, but they don't seem to be widely grown here. Maybe they aren't as cold tolerant as the native American varieties, and thus more restricted for where they can be grown?

The parallel question is why Europe doesn't seem to be having as many problems with blight if their trees are susceptible. I think it's partly that the disease just isn't as prevalent yet, and partly that there are some "odd" biological controls being used there that for some reason don't work as well in the US: https://portal.ct.gov/CAES/Fact-Sheets/Plant-Pathology/Prote...

[balaji1]

would it be possible to cross the plants the other way? Make the European/Asian ones big and tasty like the American ones. I am sure there are people thinking about this full time and would have much better ideas, but just wondering.

[pjlegato]

Yes. The American Chestnut Foundation has been working on that for several decades; not quite there yet, but it's probably possible.

More at https://tacf.org/