Response of Three Faba Bean (Vicia faba L.) Cultivars to Rhizobium Inoculation under Gypsiferous Soil Conditions

• Neven A. Abdullah*1, Zenalabden A. Handl2

  Author

• Noor Salah Rijab1*, Shahad M. Tawfeeq2

  Author

          The present study was conducted at the Research Station of the Department of Soil Science and Water Resources, College of Agriculture, Tikrit University, during the 2025–2026 growing season to evaluate the effect of Rhizobium inoculation on the growth and productivity of three faba bean (Vicia faba L.) cultivars (Local, Italian, and Turkish) grown under gypsiferous soil.  Gypsiferous soils are soils containing appreciable amounts of gypsum (CaSO₄·2H₂O), which can substantially influence their physical, chemical, and biological properties.

The results demonstrated that Rhizobium inoculation significantly improved most of the growth and yield characteristics of all evaluated cultivars. Inoculated plants exhibited significant increases in plant height and the number of root nodules, confirming the establishment of the symbiotic association between the host plant and Rhizobium, which enhanced biological nitrogen fixation. Consequently, inoculated plants produced a significantly higher seed yield per plant compared with non-inoculated plant.                                                                                       

The physiological responses also showed marked improvement following inoculation, particularly in chlorophyll content, indicating enhanced photosynthetic efficiency as a result of increased nitrogen availability through biological nitrogen fixation. Furthermore, genetic analysis revealed considerable genetic variability among the studied cultivars. High broad-sense heritability estimates were recorded for several important traits, including the number of root nodules and seed yield per plant, suggesting that these traits can be effectively improved through direct selection in breeding programs.                                                                   .                                                                       

Among the evaluated cultivars, the local cultivar consistently outperformed the Italian and Turkish cultivars in most of the investigated traits, demonstrating adaptation to gypsiferous soil conditions and a greater positive response to Rhizobium inoculation.                   .            

Overall, the findings indicate that Rhizobium inoculation represents an effective and environmentally sustainable strategy for improving the growth and productivity of faba bean cultivated in gypsiferous soils while reducing dependence on synthetic nitrogen fertilizers. The results also emphasize the importance of selecting cultivars with superior performance under the tested conditions to maximize crop performance and productivity under gypsiferous soil conditions.                                            .                                            

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