Salinity adaptability responses of wild soybean (Glycine soja Sieb. & Zucc.) under high saline soil stress over whole growth period

Abstract

Wild soybean is expected to improve stress tolerance of soybeans. However, few salt-tolerance identifications are done through whole growth period in this plant. We identified 895 wild soybean samples in a high-salinity soil during the whole growth period. The results showed that there were five types in salinity adaptability response (A, non-germinable; B, seedling death; C, before-flowering death; D, before-maturity death and E, lived to seed maturity). Under high-salinity conditions, the most severe loss was above-ground dry weight (lost 87.25%) followed by yield per plant (82.58%), the number of seeds per plant (73.71%). However, 100-seed weight had a relatively low reduction (40%). The number of seeds per plant, 100-seed weight, above-ground dry weight, harvesting index, growth period, and plant height were significantly positively correlated with yield mainly indirectly via the number of seeds, with higher indirect path coefficients. The highly salinity-tolerant lines (E type) possessed more rapid growth and lesser growth inhibition, however, they were evolved into different levels of adaptability to salinity according the comprehensive assessment D values. Our present study suggested that early or short-term or staged-identification would have the hazard of misjudgement of salinity tolerance and whole growth period identification should be adopted for soybean breeding program.