Modulation of quality and yield in saffron (Crocus sativus L.) through endophytic fungi and silicon as a novel bio-stimulant under deficit irrigation

Saffron (Crocus sativus L.) is one of the most valuable medicinal plants, but its production is highly constrained by drought stress and excessive dependence on chemical fertilizers, which adversely affect both yield and quality while raising environmental concerns. The aim of this study was to evaluate the impact of endophytic fungi (Penicillium chrysogenum and Serendipita indica) and silicon concentrations under different irrigation regimes on growth, yield and nutritional quality of saffron (Crocus sativus L.) with an intention to reduce reliance on chemical fertilizers utilizing sustainable agricultural practices. This experiment was conducted as a factorial experiment in a completely randomized block design with 27 treatment combinations of Penicillium chrysogenum, Serendipita indica, silicon, and different irrigation levels with three replications during the 2022-2023. Application of Penicillium chrysogenum, and Serendipita indica fungi, solely or in combination with silicon significantly enhanced the stigma fresh weight, stigma dry weight, saffron yield, stigma length, daughter corm number, daughter corm weight, leaf length and number, leaf dry weight, root length, root fresh and dry weight, picrocrocin and safranal. The treatment of Serendipita indica + 200 ppm silicon was the most effectiveness, so application of Serendipita indica + 200 ppm silicon caused increases by 419.1, 29.2, 279.4, 286.5, 284.5, 55.4, 371.2, 316.9, 120.8, 163.9, 312.4, 177.6, 116.5, 116.5, 40.0, and 157.8%, respectively in the values of stigma fresh weight, stigma dry weight, saffron yield, stigma length, daughter corm number, daughter corm weight, leaf length, leaf number per plant, leaf dry weight, root length, root fresh weight, root dry weigh, picrocrocin and safranal. We recommend the application of Serendipita indica + 200 ppm silicon in order to enhancement growth and flowering, saffron yield, and saffron nutritional quality in non-stress and drought stress condition. In conclusion, this study provides a promising strategy for sustainable saffron production, and future research should validate these findings under diverse agro-climatic conditions and explore their long-term economic feasibility.