| NUE | Nitrogen Use Efficiency |
| GC–MS | Gas Chromatography-Mass Spectrometry |
| LNT | Low-N tolerant (PEHM-2) |
| LNS | Low-N sensitive (HM-4) |
| HMW | High Molecular Weight Compounds |
| LMW | Low Molecular Weight Compounds |
| PCA | Principle component Analysis |
| PC1 | Principle Component 1 |
| FDR | False Discovery Rate |