Research Article published by International Journal of Current Microbiology and Applied Sciences Volume 6 Number 3 (2017)A two season field experiment and a single season screen house experiment were conducted to assess the effect of water stress periods and rhizobial inoculation in five (5) P. vulgaris (L.) cultivars. The experiment consisted of 2 levels of rhizobia (with and without inoculation), two stress levels (With and without stress) and five cultivars of P. vulgaris (L.) (KAT B9, KAT B1, F9 Kidney Selection, F8 Drought Line and JESCA). The field experiment was conducted for two consecutive seasons, while the screen house study was done in a season. Results showed that proline content (μmol g-1.FW) was higher in inoculated and water stressed treatments. Variety number 4 (F8 Drought Line) and 5 (JESCA) significantly recorded higher proline content in field experiment as compared to the rest. However, in the screen house experiment, variety 2 (KAT B1) and 4 (F8 Drought Line) significantly accumulated more proline than the other tested varieties. Significant interactive effects were also observed between inoculation, water stress periods and the tested P. vulgaris varieties.