Question: what is the best natural method of plant breeding?

Alison Tidy answered on 30 Mar 2023:

So traditional breeding is taking plants from the same species but grown in different locations over thousands of years so adapted to their environment (known as different cultivars, or wild relatives if not grown for food), and then these are crossed and tested for different traits. Eg disease survival, higher yield, drought tolerance. Once they have found a trait they are interested in they want it in their high yielding cultivar so they will backcross back to that parent many times (at least 10), all the time checking for their new trait. They then should end up with a line that has all the genome found in their high yielding cultivar (e.g. bread wheat) with some additional genome from the cross that gives the trait that they breed in (e.g. disease resistance).

Another natural method they will use is to cross different species to create a hybrid (50% mix from both parents). These hybrids tend to have higher yield (approx 30%) and better tolerance to stress such as drought, heat or diseases. The hybrid seed is sold to the farmers and if you look at seed packets in the shops they will often say F1 hybrid especially for vegetables but sometimes flowers as well.