The effect of a commercial rhibozial inoculant on nodule and tuber formation and plant health in legumes.

The majority of legumes form nitrogen-fixing symbioses that help them access necessary nutrients under limiting conditions. Several legumes, such as jicama and Apios are known to form tuberous roots that store starches for regrowth after winter. These tubers can act as bio drills to naturally break up compacted soils. I wanted to see if a commercial inoculant had an effect on plant health. I hypothesized that a commercial rhizobial inoculant would enhance plant growth and tuber development compared to non-inoculated legumes. To test this hypothesis, two species of tuberous legumes: Psophocarpus tetragonolobus (winged bean), and Lathyrus liniolius (everlasting pea) were grown with and without inoculant. In addition, some of the plants were grown in autoclaved, sterilized soil to see if there was an effect on the plant compared to untreated soil. Also grown was Melitous alba (white sweet clover), which served as a control for inoculant use. After the plants were grown for eight weeks, WinRhizo, a software for imaging and measuring plant roots, was used to photograph root systems and ANOVA values were calculated using RStudio. I found that Winged Bean’s height and number of nodules was statistically significant (p=0.0347) as well as its’ root biomass (p=0.0167). Unexpectedly, several types of nodules formed based on the treatment. One type of nodule was round and lobed, often clustered; while the other was smaller, linear projections scattered along the roots. These observations suggest that different bacteria associated with the plants. Overall, these findings indicate that the addition of an inoculant improves the chances of nodule formation and tuber growth. Winged bean readily forms a tuber and everlasting pea exhibited tuber formation. Several legumes that can function as natural bio drills, fix nitrogen, and are edible could become valuable crops for Vermont farmers