Mutant Classes
| Nod- | No nodulation or nodulation is blocked at very a early stage |
| Nod+Fix- | Nodules do not fix nitrogen |
| Nod+Fix+- | Nodules with reduced activity of nitrogen fixation |
| Nod+Fix+ | Normal nodulation and nitrogen fixation |
| Nod+- | Smaller size or less number of nodules or delayed nodulation |
| Nod++ | Supernodulation or hypernodulation |