The Effect of Foliar Application of Seaweed Extract and Some Nutrients on Flowering and Apocartenoid Content in Saffron Stigma

Recognizing the potential role of seaweed in improving saffron yield and the utilization of micronutrient elements like Ca, Mg, Fe, and Mn to enhance stigma yield, an experiment was conducted. The study investigated the impact of foliar spraying of seaweed extract and selected nutritional elements on saffron's quantitative and qualitative traits of saffron.This research was conducted, as factorial based on a randomized complete block design (RCBD) with four replications during 2021-2022 in Neishabur, Iran. The first factor consisted of seaweed extract (0 and 2 L.ha-1) and the second factor consisted of foliar application of nutrients including no foliar application (as control), and the defender of some elements including iron (1.5 L.ha-1 containing Fe, N, and amino acids), zinc, boron (1 L.ha-1 containing B and amino acids), manganese (1.5 L.ha-1 containing Mn, Zn and S), magnesium and calcium (2 L.ha-1 containing Ca and N). The use of all nutrients compared to the control (no-nutrients) and the use of seaweed extract compared to no-seaweed application caused an increase in flower and stigma yields. Based on the interaction effects of the experimental factors, the highest number of flowers (68.8 No.m-2) was obtained in the combined application of manganese and seaweed extract, the highest flower yield (33.5 g.m-2) was gained with the combined application of seaweed and boron, and the highest dry stigma yield (0.48 g.m-2) was obtained from the simultaneous application of magnesium and seaweed extract, which were 63.8, 16.7 and 17.0%, more than the control treatment (no-seaweed & No-nutrients), respectively. Without nutrient application, the utilization of seaweed extract resulted in a notable rise in the Picrocrocin content of the stigma by 15.9%, Crocin by 9.5%, and Safranal by 10.6% compared to the absence of seaweed application.Combined consumption of calcium with seaweed increased the content of Picrocrocin and Crocin, while simultaneous application of other nutrients with seaweed did not improve these indices. The highest and the lowest content of Safranal (37.7 and 32.35 absorption at 330 nm) were obtained from magnesium + no-seaweed and control (no-seaweed & no-nutrients) treatments, respectively. Overall, although all of the studied elements combined with seaweed extract improved stigma yield in order to increase stigma yield, application of Mg in combination to seaweed recommended and to enhance saffron quality using seaweed suggested.