Evaluation of Integrated Application of Arbuscular Mycorrhizal Fungi and Silicon to Improve Growth and Yield of Sunflower under Salt Stress

Salinity is the most devastating abiotic stress that exacerbates its detrimental impacts on agricultural production. Judicious application of silicon fertilizer and arbuscular mycorrhizal fungus (AMF) may have potential to mitigate the adverse impact of salt stress on sunflower. Therefore, the current study aimed to evaluate the integrated application of silicon fertilizer and AMF to enhance growth, physiological responses, yield performance and yield attributes of sunflower under salt stress. Pot experiment was conducted at Professor Dr. Purnendu Gain field laboratory where factorial experiment consists of three factors, namely; Si dose (non-treated control, 150 kg ha^-1, 300 kg ha^-1 and 450 kg ha^-1 designated as Si₀, Si₁₅₀, Si₃₀₀, Si₄₅₀ respectively); water salinity levels (control- 0.54, 4, 8 and 12 dS m^–1) and two levels of AMF inoculation (with AMF [+AMF] and without AMF [–AMF]). Factorial experiment was laid out where treatment combinations were assigned completely randomized design (CRD) with three replications. All of the evaluated growth, physiological traits and seed yield of sunflower significantly declined by various levels of water salinity but silicon treated plants upgraded leaf relative water content, leaf greenness and membrane stability index 45%, 17 % and 60 %, respectively, with lower electrolyte leakage (15 %) at 12 dS m^–1 water salinity compared to non-treated plants. In addition, the maximum proline concentration was observed with Si₄₅₀ which was 19% and 28% higher than the control (0.54 dS m^–1) for AMF-inoculated plants and non-inoculated plants at water salinity 12 dS m^-1. AMF inoculated plant increased the head weight and seed number plant^-1 by 23% and 41% respectively compare to non-inoculated plant.  At 12 dS m^–1 salinity level, plants treated with Si₄₅₀ had promoted seed yield by 56% and 50% in AMF inoculated and non-inoculated plant than Si₀. Taken together, it might be inferred that integrated application of Si and AMF had boosted up morpho-physiological traits, yield attributes and seed yield of sunflower and to ameliorate the deleterious effects of salt stress.

• Supervision