DOI: 10.5061/dryad.rfj6q57j1
title: Alfalfa (Medicago sativa) salt tolerance/mutualistic bacteria inoculation

description: Alfalfa (Medicago sativa) is a ubiquitous forage legume crop, responsible
 for the nutrition of many of the world's livestock animals.
 Unfortunately, alfalfa suffers from insufficient levels of salinity
 tolerance in many semi-arid regions around the world, including western
 Canada. To attempt to find ways to mitigate salinity stress in alfalfa,
 this study combined conventional breeding techniques with inoculation by
 mutualistic soil bacteria. Three alfalfa generations sequentially selected
 for improved salt tolerance were inoculated with either highly
 salt-tolerant (H. maura), moderately-tolerant (Ensifer meliloti) bacteria,
 or a 60 kg/ha nitrogen amendment in either non- (0 dS/m), moderate-(8
 dS/m), or highly (16 dS/m) saline soil in the greenhouse. Plants were
 assessed for success in saline conditions through root/shoot biomass
 measurements, shoot height, chlorophyll content, number of stems, and root
 and shoot osmoprotectant concentrations (proline, glycine betaine, and
 trehalose). Results showed that rhizobium was the most beneficial bacteria
 to alfalfa under moderately saline conditions, and that generation 2
 appeared to be the most salt-adapted alfalfa population. Additionally,
 nitrogen amendments appeared to provide benefits to biomass and
 osmoprotectant production. The salt-tolerant bacteria H. maura failed to
 provide any benefits to alfalfa growth, suggesting that reported benefits
 from the previous studies may be genotype/location specific. The improved
 performance of generation 2 relative to generation 3 may suggest the onset
 of an inbreeding depression, to which alfalfa (being an outcrossing
 species) is susceptible. These findings suggest nitrogen may be an
 important nutrient for alfalfa under moderately salt-stressed conditions,
 and that intense selection may be less effective than moderate selection
 intensity for the improvement of salinity tolerance.
description: # Alfalfa (*Medicago sativa*) salt tolerance/mutualistic bacteria
 inoculation
 [https://doi.org/10.5061/dryad.rfj6q57j1](https://doi.org/10.5061/dryad.rfj6q57j1) ## Description of the data and file structure Variables: * shoot/root biomass (g) * height (cm) * chlorophyll content (with 3x contributing values, unitless) * plant counts * Number of stems (Tillers) * nodulation scores (1 (low)-9 (high), "inactive" nodules are also noted), * spectrophotometric absorbance values (unitless) for three osmoprotectants (proline, glycine betaine, trehalose) * quantity values (Mg) * concentration values (mg/g plant tissue) Lastly, there are censor identifiers for proline values, as some samples contained greater concentrations of proline than the instrumentation could determine (1=uncensored, 0=censored). Treatments included plant generation (1, 2, 3, 'Halo'=Check), 5 "bacteria" treatments (C=Control, CN=60kg/ha nitrogen amendment, E= *Ensifer meliloti*, H=*Halomonas maura*, or H+E = *E.meliloti* + *H.maura*), and salinity level (0, 8, 16 dS/m). There were 6 total replications (Rep=6), and the experiment was replicated twice (R=2). Time is measured in days. Initially, there were 6 plants/pot, which were thinned down to 3 plants/pot at 35 days. ## Sharing/Access information N/A ## Code/Software N/A