The variation of some growth, agronomical and biochemical parameters of Vigna unguiculata (L. Walp) under salinity stress were investigated in the greenhouse and farm conditions. Plants were subjected to 0, 50, 100 and 200 mM NaCl. The increases of NaCl in the culture medium significantly (P< 0.001) decreased the growth parameters (number of leaves, noose diameter, leaf area and stem height), dry biomass (roots, shoots and total), chlorophyll contents and micronutrients (Zn, Fe and Mn) from 100 mM NaCl. Macronutrients (K, Ca and Mg) and K/Na ratio significantly (P < 0.001) decreased in plant partitioning with increasing salinity. The metabolites (proline, total soluble carbohydrates, soluble proteins, total free amino acids, total phenolic and flavonoids contents) significantly (P < 0.001) increased from 50 mM NaCl in variety Ekomcalle compared to Mouala GG and could be considered as biochemical indicators of early selection and osmotic adjustment ability for salt tolerant plants. At 50 mM NaCl, a relative tolerance of variety Ekomcalle compared to Mouala GG for all agronomic parameters (the flowering time, number of flowers per plant, number of pods/plant, number of seeds/pod, pod yield, seed yield and harvest index) was observed suggesting that Ekomcalle could increase cowpeas production on salty soils.
Keywords: Vigna unguiculata, salinity, growth, metabolites, mineral uptake, agronomic parameters.