Other small grains such as barley and rye have some diseases in common with wheat and are less than ideal as preceding crops. However, they are not as bad as wheat. Smooth brome is a strong source of take-all root rot and should be avoided as a preceding crop. Weedy brome or cheat species also carry take-all. Take-all can be a big problem when wheat follows alfalfa infested with weedy bromes.
Corn is the number one source of scab inoculum.
Although the scab pathogen is mobile, corn preceding wheat can result in higher scab levels. Certain rotations could be planned that contain a mixture of tillage practices, depending on the preceding crop. For example, corn could be no-tilled into wheat stubble, but wheat could be planted after corn following disking or plowing to reduce inoculum. This option would not be appropriate for highly erodible land. Another thing to consider is that mulch tillage may reduce inoculum levels compared to no-till.