Identifying Soybean Germplasm with Tolerance to Dehydration and Salinity Stresses

Germplasm characterization can enhance the management and utilization of plant germplasm conserved in genebanks worldwide. This study was conducted to characterize 774 diverse soybean [Glycine max (L.) Merr.] accessions, mainly conserved at Plant Gene Resources of Canada (PGRC), through a laboratory seedling vigor test under polyethylene glycol (PEG)-induced dehydration stress and 72 selected accessions through a greenhouse salinity test. The PEG-based test identified 95 accessions that showed vigorous seedling growth in Petri dishes containing 20% (w/v) PEG 6000 solution. The salinity test revealed 58 accessions that produced total seed yields per plant ranging from 0.03 g to 1.47 g under severe salinity stress (EC_i 16.1 dS m^-1). Six accessions originating from five countries displayed higher salt tolerance than the Canadian salt-tolerant cultivar OAC Ayton, but the latter still had the highest seed yield. One unique accession, CN29789, originating from China and named 'Hei Nung No.18', consistently showed high tolerance to both dehydration and salinity stresses and had vigorous root growth under severe salinity stress. These findings are significant, as they not only provide useful germplasm for soybean genetic improvement for abiotic stress tolerance but also demonstrate the value of characterizing plant germplasm conserved in a genebank for better utilization.