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

    Asked by anon-361241 on 30 Mar 2023.
    • Photo: Alison Tidy

      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.

    • Photo: Sam Mugford

      Sam Mugford answered on 30 Mar 2023:

      It depends on what you think “natural” means. Traditional plant breeding can involve crossing different species of plants that would never breed in nature. Wheat that we grow to make bread came from a cross like this. Three different species of grass were crossed together (thousands of years ago) to make a plant that would be very unlikely to survive in nature without farmers to look after it.

      On the other hand, methods like genetic modification of plants that people might think are very un-natural use a natural bacteria called agrobacterium. Agrobacterium naturally infects plants and transfers its own DNA into plants. So maybe this is more natural than some traditional plant breeding methods?

      I dont think that the word “natural” is very useful, because it means different things to different people, very often depending on how they feel about science and technology.