Response of Vigna sinensis and Phaseolus vulgaris to varied salt stress levels

Crop response to salinity may varies among species, might be due to ions accumulation and yield components contribution in yield. This study was conducted to evaluate the effects of varying salinity (0, 1.5, 3.0, 4.5 and 6.0 dS m(-1)) on cowpea (Vigna sinensis) and common bean (Phaseolus vulgaris) to distinguish their salinity tolerance thresholds. Although salinity reduced growth, yield, shoot and root potassium content as well as increased shoot and root sodium content in both crops; these alterations were lower in cowpea than common bean. So that the highest salinity level caused 60% and 50% reduction in grain yield and 59% and 49% reduction in dry matter in common bean and cowpea, respectively. Harvest index and leaf number could be independently of salinity stress. Multivariate regression analysis showed that grain number plus dry matter and thousand grain weigh plus dry matter were the most effective traits on grain yield of common bean and cowpea, respectively. Since thousand grains weight was found to be less sensitive trait to salinity, so cowpea was less sensitive under salinity stress compared to common bean. The same argument was followed in salinity threshold analysis, where salinity tolerance threshold was 3.62 for common bean and 4.36 dS m(-1) for cowpea. The results of this study indicated that more Na accumulation in root and less translocation into shoot might be responsible for higher salinity tolerance in cowpea crop. (C) 2014 IASE Publisher All rights reserved.