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Salinity Tolerance of Winged Bean as Compared to that of Soybean

Weil, Ray R., Khalil, N. A.
Agronomy journal 1986 v.78 no.1 pp. 67-70
Psophocarpus tetragonolobus, Glycine max, cultivars, saline soils, seed germination, nitrogen fixation, phytotoxicity, salt tolerance, greenhouse experimentation
Winged bean [ (L.) DC] has been called an underutilized crop with the potential to become a major protein crop for the tropics and subtropics. As with soybean [ (L.) Merr.] the introduction of winged bean to warm arid regions will be affected by tolerance to salinity. In this study a prolific Sri Lankan winged bean accession (‘SLS47’) and two soybean cultivars (‘Jackson’ and ‘Lee’) were grown in pots of sandy soil amended with NaCL to give saturated paste electrical conductivities (EC) of 0.5, 2.5,4.5,6.5 and 8.5 dS m. At 0.5 dS m, dry matter accumulation (0.84 g plant), nodule mass, (32 mg plant), and tissue N (24 mg Ng) of winged bean were similar to those of both soybean cultivars. At 65 d after planting, however, specific nitrogenase activity by acetylene reduction assay was much lower for the winged bean (60 pmol ethylene gh) than for the soybean (160 to 190 amol ethylene gh). The results indicated that winged bean was at least as tolerant as Lee soybean and more tolerant than Jackson. Though stunted, at 8.5 dS m winged bean showed significantly less foliar injury than did either of the soybean cultivars. For the soybean, the tissue N content was unchanged, but for winged bean it increased significantly with increasing salinity, suggesting that dry matter accumulation,especially by winged bean, was more sensitive to salinity than to N fixation.