Saffron Agronomy and Technology

Abstract This study was conducted to evaluate the effects of priming saffron corms with different auxin concentrations (0, 1, 2.5, 5, 10, 25, 50, 100, 250, 500, and 1000 mg.kg^-1) on vegetative, reproductive, and propagation traits under aeroponic conditions. A completely randomized design with three replications was used during 2021–2022 at the research laboratory of the Faculty of Agriculture, Shahid Bahonar University of Kerman, Iran. The results revealed that saffron responses to NAA pre-treatment were predominantly dose-dependent and exhibited a biphasic pattern. At the propagative level, the greatest stimulation of lateral bud emergence occurred at lower concentrations. Specifically, 5 and 10 mg.kg^-1 significantly increased the mean number of lateral buds by approximately 75% and 66%, respectively, compared with the control. Conversely, intermediate concentrations, particularly 50 and 100 mg.kg^-1, partially inhibited bud formation. The lowest value (1.4 buds) was observed at 250 mg.kg^-1. Reproductive traits followed a quadratic, dose-responsive trend. The maximum values for flower number, flower yield, and stigma dry weight were observed at 250 mg.kg^-1. Leaf length (14.4 cm) and leaf dry weight (2.68 g per plant) also peaked at this concentration. With respect to corm multiplication, the highest number of reproductive corms per 100 mother corms was recorded at 10 mg.kg^-1 (525 corms). The lowest value (258 corms) was observed at 250 mg.kg^-1. However, the mean reproductive corm weight was maximized at 250 mg.kg^-1(11.06 g). The distribution of corm weight was strongly influenced by auxin concentration. Lower doses (5–10 mg.kg^-1) produced a higher proportion of small corms (<5 g; ≈73% at 5 mg.kg^-1 and ≈63% at 10 mg.kg^-1), whereas 250 mg.kg^-1increased the proportion of large corms (>10 g) to about 45%. Overall, the findings indicate that lower auxin concentrations (5–10 mg.kg^-1) are more suitable for mass propagation. Intermediate concentrations particularly 250 mg.kg^-1 are recommended to enhance flower yield and produce larger corms, which are desirable for economic and production purposes.

Abstract The shift toward sustainable medicinal plant production underscores the importance of biological inputs. This study evaluated the effects of humic acid application, mycorrhizal inoculation, and two irrigation regimes on reproductive growth and quality of saffron (Crocus sativus L.). The experiment was conducted as a split-split plot based on a randomized complete block design (RCBD) with three replications, where irrigation intervals (20 and 40 days) were the main plot, humic acid (0 and 5 kg.ha⁻¹) was the sub-plot, and mycorrhizal inoculation (noninoculated, Glomus mossea, and G. intraradices) was the sub-sub plot. The studied traits were the number of flowers, flowering rate, flower yield, petal yield, style yield, and stigma yield, as well as stigma quality parameters (crocin, picrocrocin, and safranal content). Results indicated that the triple interaction of experimental factors was significant on all studied traits. The shortest irrigation interval (20 days) combined with humic acid application and G. mossea inoculation significantly increased fresh flower yield (79.63 g.m⁻²), dry stigma yield (0.88 g.m⁻²), style yield (0.22 g.m²), and petal yield (9.88 g.m ²). Crocin content was highest (274.5, absorbance of 1% aqueous solution at 440 nm) under 40-day irrigation intervals with humic acid and G. mossea inoculation, while safranal (35.80, absorbance at 330 nm) and picrocrocin (124.5, absorbance at 257 nm) improved under 20-day irrigation intervals with humic acid and G. mossea. Conversely, extended irrigation intervals (40 days) without humic acid and without mycorrhizal inoculation resulted in the lowest crocin and safranal content. Overall, the findings demonstrate that combining humic acid with G. mossea inoculation under frequent irrigation optimizes both the quantity and quality of saffron. It was concluded that although the use of organic inputs is beneficial, the results of their single application may differ from those of their combined application. On the other hand, the interaction among two or more of these inputs can also vary depending on conditions, including water availability and the type of mycorrhizal species.

Abstract Evaluating and quantifying agricultural ecosystem services in saffron-based agroecosystems is essential for understanding their economic value and informing sustainable management. This study aimed to estimate and monetize multiple ecosystem services and disservices in saffron fields. Researchers collected primary data by using a structured questionnaire with saffron growers from selected counties in Khorasan Razavi and South Khorasan provinces (Mashhad, Torbat-e Jam, Torbat-e Heydarieh, Khalilabad, Bardeskan, Birjand, Zirkouh, and Boshruyeh), resulting in 120 completed questionnaires. The study estimated the value of five saffron ecosystem services—food production, oxygen production, biodiversity, conservation, and the absence of migration—and two disservices —greenhouse gas emissions and phosphorus and nitrogen leakage. Results showed that the total net value of ecosystem services in the studied fields was 39,353.6 US$/hectare per year. Prevention of rural migration, identified as a cultural service, was valued at 24,579.3 US$/hectare per year. Cultural and provisional services and biological diversity made up 62, 43, and 5.8% of the total ecosystem service value in saffron fields. These findings highlight the importance of assessing both ecosystem services and disservices in saffron agroecosystems to guide sustainable management and policy decisions.

Abstract Saffron is a high-value crop of strategic and economic importance in Iran, particularly in semi-arid regions. Its productivity and quality are influenced by complex interactions among agronomic, environmental, and management factors. This study aimed to identify and analyze the key determinants of saffron yield (stigma yield per hectare and per kilogram of fresh flowers) and quality indices (crocin, picrocrocin, and safranal) using a datadriven approach. In 2023, data were collected from 99 saffron farms across eight counties in Razavi Khorasan Province, encompassing 75 variables that recorded climate, soil, management practices, and farmer demographics. Least Absolute Shrinkage and Selection Operator (LASSO) regression with 10-fold cross-validation was applied for variable selection and predictive analysis. Results indicated that stigma yield per hectare was primarily influenced by corm planting rate, organic fertilizer, corm weight, and field area, achieving R² = 0.63 and RMSE = 3.75 kg.ha⁻¹. For stigma yield per kilogram of fresh flowers, phosphorus fertilization, corm weight, and planting density were the strongest positive predictors, with R² = 0.70 and RMSE = 0.69 g.kg⁻¹. Moderate positive effects were observed for organic fertilizer and irrigation frequency, while quadratic effects suggested threshold responses for corm size and irrigation. For quality traits, phosphorus was the dominant positive predictor of crocin (β = 18.3) and picrocrocin (β = 3.97), whereas altitude and foliar spray frequency negatively affected picrocrocin and safranal. The effects of nitrogen and sulfur fertilizers were minor and nonlinear. Simplified models retained predictive accuracy (R² = 0.70), improving practical applicability. These findings highlight the importance of sitespecific phosphorus management, corm quality monitoring, and optimized irrigation for enhancing saffron yield and quality. LASSO regression effectively identified influential variables, supporting precision agriculture and decision-support tools for sustainable saffron production under semi-arid conditions.

Abstract This study evaluates the technical efficiency of saffron farms in Torbat Heydarieh and Zaveh Counties, ‎located on northeastern Iran, using a two-stage double-bootstrap Data Envelopment Analysis (DEA) ‎approach. Cross-sectional data were collected from 108 saffron producers across six districts, and ‎technical efficiency (TE) scores were estimated under variable returns to scale (VRS) with an input-‎oriented DEA model. The bias-corrected double-bootstrap procedure of Simar and Wilson (2007, ‎Algorithm 2) was applied with 1000 replications to ensure consistent inference and robust estimation. ‎Results reveal that the Farrell efficiency estimates tend to overstate farm technical efficiency by ‎approximately 25 percent. I detected significant regional disparities in efficiency scores (χ² = 12.74, p < ‎‎0.05), with the highest mean efficiency observed in Kadkan (0.32) and the lowest in the Central district ‎‎(0.17). The truncated bootstrap regression identified an inverted U-shaped relationship between farm ‎age and efficiency, where efficiency initially increases with farm age but declines beyond a certain ‎point. Experience in saffron cultivation had a strong positive and statistically significant effect on ‎efficiency (p < 0.01), while education level and farmer’s age were not significant predictors. Slack ‎analysis revealed considerable input-specific inefficiencies and spatial heterogeneity in slacks. On ‎average, farms could reduce water use by 706.88 m³/ha, land by 3.04 ha, corm use by ‎528.10‎ kg/ha, and ‎labor by 20 person-days/ha without reducing output.‎

Abstract Saffron, as one of Iran's strategic products, has stigmas and petals rich in phenolic compounds and anthocyanins, which can serve as a natural source of color and antioxidants. However, anthocyanins are unstable compounds that degrade rapidly under environmental factors such as light, heat, and oxygen. This study aimed to improve the stability and efficacy of bioactive compounds in saffron petals by microencapsulating them with sodium caseinate, enabling their application in dairy products. The saffron petal extract was prepared and, after concentration, mixed with the wall material, sodium caseinate, at different core-to-wall ratios (1:3, 1:5, and 1:7), and microencapsulated using the freeze-drying method. The control sample included the unencapsulated extract. Then, the physicochemical properties of the powders, including anthocyanin content, moisture, water activity, solubility, density, and flowability indices, were evaluated. The results indicated that the 1:7 ratio exhibited the best characteristics, including greater anthocyanin stability, reduced moisture and water activity, improved flowability, and increased solubility.