Impact of Sinorhizobium meliloti strains and plant population on regrowth and nodule regeneration of alfalfa after a freezing event

Abstract Purpose The increase in frequency of freeze–thaw episodes with the diminution snow cover protection due to climate change compromises winter survival alfalfa ( Medicago sativa L.). Symbiosis cold-tolerant rhizobial strains can improve ability survive and grow under stressful conditions. Methods Six Sinorhizobium (Ensifer) meliloti were tested combination two populations bred differ their levels freezing tolerance. Plants each different grown for eight weeks a growth chamber before being exposed temperatures promoting acclimation cold. then stress (-11ºC) regrown three weeks. Shoot, root nodule biomass measured cold after stress. Results After stress, population A-TF7 had shoot biomasses that respectively 19% 15% larger than cultivar A-TF0. Alfalfa plants inoculated strain NRG34 showed both higher dry weight any other strains. Assessment damages on nodules largest proportion undamaged or regeneration zone. Conclusion This study shows first time relationship between regrowth latter linked showing less damage. Our results demonstrated choice S. adapted are complementary increasing persistence .