Assessment of the Flowering Capacity of Saffron (Crocus sativus L.) Corm under Field and Controlled Environmental Conditions in Sari Plain Region

The present research was conducted in order to achieve the best method of planting and obtaining the maximum yield of flowers and stigmas of saffron (Crocus sativus L.) in two stages in Sari Plain. The first stage was carried out in the research farm of Sari Agricultural Sciences and Natural Resources University during 2021-2022 as split plots on randomized complete blocks design with three replications, in which the experimental treatments included drainage depth (15, 30, and 45 cm) in the main plots and three drainage distances (50, 100 and 150 cm) in the subplots. In the second stage, the produced corms were stored for three months in the incubation environment, and then, the corms were transferred to two different environments of aeroponic and field to evaluate saffron's flower and stigma performance. The measured traits included the number of produced flowers, average flower weight, dry stigma weight in both field and aeroponic, and the amount of safranal, picrocrocin, and crocin and in aeroponic conditions. The evaluation of reproductive traits of saffron under aeroponic showed that with increasing the depth of the drain and decreasing the distance of the drain, traits such as the number of flowers, flower weight, and stigma dry weight increased; when the maximum value of these traits, equivalent to 4744 flowers.m-2, 1423 g.m-2, and 10.7 g.m-2 were observed at 30 cm drainage depth and 100 cm drainage distance, which did not have a significant difference with 45 cm drainage depth treatment and 100 cm drainage distance. In addition, the results showed that the amount of picrocrocin decreased with increasing the depth of the drain and the distance of the drain. In addition, no significant difference was observed between different treatments for crocin content. Comparing the reproductive traits of plants under two cultivation conditions, namely air, and field, revealed a reduction of 21%, 20%, and 12% in the number of flowers, fresh flower weight, and dry weight of stigma, respectively, within the field conditions. In summary, the findings suggest that, for optimal saffron production in coastal areas, the propagation of corms in the field at depths of 30 cm and 100 cm with proper drainage, followed by flowering of the propagated corms through aeroponic cultivation, could be a viable and economically sound approach for one-year saffron cultivation in the Sari plain region.