Abstract:

Wild soybeans (Glycine soja) have such positive characteristics as salinealkali resistance, cold tolerance and disease resistance, so they play a significant role in the research on soybean gene evolution and the improvement of soybean quality and yield. We collected 227 wild soybeans from 26 sites of 14 rural towns in the Yellow River Delta, and isolated and purified rhizobia strains from wild soybean nodules. We then performed physiological and biochemical experiments, stress tolerance experiments, nodulation ability determination, nodulation wide spectrum analysis, 16S rDNA sequence determination and RAPD analysis. We isolated and purified 100 rhizobia strains from Glycine soja. Strains 3D-21, 3D-24, 3K-8 and 3K-23VS had strong tolerance against acid, alkali, salt, antibiotics, high and low temperature and stronger nodulation capability. Strain 7K-8 had stronger nodulation capability and strain K-5 had stronger stress tolerance capability. 16S rDNA sequence analysis shows that all the isolated strains belong to 3 genera and 7 species, and that RAPD analysis of similar strains exhibits obvious polymorphism. Results indicate that rich diversity exists in the rhizobia of wild soybean in the Yellow River Delta. Some strains have strong nodulation ability and/or stress tolerance ability. This research lays a foundation for the excavation and utilization of better strain resources.

Key words: wild soybean (Glycine soja), rhizobium, stress tolerance, genetic diversity