R. Han wrote:Hi all,
does anybody have a table of which cereal can cross pollinate each other?
I initially tought that at least different genera should not cross polinate, but triticale is such a hybrid between different genera.
I am asking because I would like to grow some small scale cereals from true to seed variaties and save the seed.
Triticale was hard to make. You could plant Triticale and its parents Rye, and Wheat sprinkled together in the same patch and be pretty assured they would not cross again for you. In that case you were right in your initial assumption. Just think of them as three genera. There does exist Hordeum x Triticum out there but same story- cross was hard to make, won't happen again without intervention even if you plant all three together.
Wheat is another matter. All the various species of Triticum and Aegilops may hybridize even across ploidy lines though far less frequently than within. This is how wheat came to be, as different wild species were brought together in wheat fields they formed increasingly complex hybrids.
If you want isolation for sure I would pick one wheat, one rye, one barley, one triticale, one rice and so forth with as many species as you wish.
Though that said there really is no reason on the home garden scale to necessarily keep small grain varieties separate or even necessarily species or genera.
I bought a packet of purple landrace wheat and noticed it contained some barley grains. I wrote and was assured that was true to the original, the two species were always grown together. Which stands to reason, we mix barley malt into bread flour today. Historical wheat landraces were a mix not just of wheat varieties but wheat species and crop wild relatives including jointed goat grass. Methods for hand harvest makes mixing matter far less than for commercial fields.
Under optimal conditions for outcrossing small grains might get up to 30% crossing but not everyone has the right climate for that. Though I also don't think it necessarily takes huge separation to keep varieties separate of many species of small grain. I've certainly seen photos of trial grounds with hundreds of varieties grown and while they undoubtedly rouged out hybrids they didn't require massive separations and I can't imagine the seed wasn't used.