Potential for nitrogen fixation in maize landraces

Nitrogen is an essential nutrient for plants and inorganic fertilizers used to promote plant growth account for between 1%-2% of total global fossil fuel usage. Some plants, especially legumes, are capable of forming associations with nitrogen-fixing microbes to convert atmospheric nitrogen into a form that the plant can utilize. These associations have been limited in grasses, so cereal crops require high levels of applied nitrogen fertilizer.  However, a recent paper reported that a traditional variety (i.e., landrace) of maize from Mexico called Sierra Mixe was found to host microbial nitrogen fixing microbes in mucilage (or gel) on its aerial roots (i.e., roots extending into the air rather than the soil) and benefit from the nitrogen produced (Van Deynze et al. 2018). We aim to understand the frequency of landrace varieties that are capable of producing aerial roots and mucilage and clarify how these traits may be affected by environment.