Saffron Agronomy and Technology
In collaboration Iranian Medicinal Plants Society

Determining Key Agronomic and Environmental Drivers of Saffron (Crocus sativus L.) Yield and Quality Using LASSO Regression

Document Type : Research Paper

Authors

Abdollah Dorpoor Sorkhsarayi 1
Mehdi Rastgoo 2
Ghorbanali Asadi 2
Javad Feizy 3
Mohammadhasan Fallah 4

1 PhD student in Agrotechnology, Weed Science, Faculty of Agriculture, Ferdowsi University of Mashhad

2 Professor, Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad

3 Associate Professor, Department of Food Safety and Quality Control, Research Institute of Food Science and Technology (RIFST), Mashhad, Iran

4 PhD graduate in Crop Ecology, Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad

https://doi.org/10.22048/jsat.2026.558332.1575
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.

Keywords

Climatic factors
irrigation scheduling
nonlinear effects
nutrient management picrocrocin
variable selection
Subjects
Arora, P.K., Tripathi, S., Omar, R.A., Chauhan, P., Sinhal, V.K., Singh, A., Srivastava, A., Garg, S.K., & Singh, V.P. (2024). Next-generation fertilizers: the impact of bionanofertilizers on sustainable agriculture. Microb Cell Fact, 23(1):254. https://doi.org/10.1186/s12934-024-02528-5.
Askari, Y., & Keshavarz, K. (2021). Study of planting density and corm size on saffron (Crocus sativus L.) yield in Yasuj climatic conditions. Journal of Saffron and Medicinal Plants Extension, 3(1), 51-44. (In Persian with English abstract).
Ayoubi, K. A., Eisvand, H. R., Heydari, S., & Mousavi-Fard, S. (2023). Effects of Foliar Application of Iron and Zinc Micronutrient Elements on Quantitative and Qualitative Yield of Saffron (Crocus sativus L.). Journal of Saffron Research, 11(1), 78-66. (In Persian with English abstract). https://doi.org/10.22077/jsr.2023.6083.1206.
Azizi, G., Moosavi, S. G., Seghatoleslami, M. J., & Fazeli Rostampour, M. (2023). Effect of different irrigation systems and fertilizer types on saffron corm production. Journal of Medicinal Plants and By-Products, 12(4), 339-348. https://doi.org/10.22092/jmpb.2022.356222.1410.
Bouyoucos, G. J. (1936). Directions for making mechanical analyses of soils by the hydrometer method. Soil Science, 42(3), 225-230.
Bradstreet, R. B. (1954). Kjeldahl method for organic nitrogen. Analytical Chemistry, 26(1), 185-187.
Cardone, L., Castronuovo, D., Perniola, M., Scrano, L., Cicco, N., & Candido, V. (2020). The Influence of Soil Physical and Chemical Properties on Saffron (Crocus sativus L.) Growth, Yield, and Quality. Agronomy, 10(8), 1154. https://doi.org/10.3390/agronomy10081154. 
Doostdar Mahmudabad, M., & Azadi Brice, S. (2022). Studying the effect of irrigation and drainage methods on root and crown rot disease of kiwi tree. Seventh International Congress on Agricultural and Environmental Development with Emphasis on the United Nations Development Program.
Esmaealzadeh D, Moodi Ghalibaf A, Shariati Rad M, Rezaee R, Razavi B. M., & Hosseinzadeh H.  (2023). Pharmacological effects of Safranal: An updated review. Iranian Journal of Basic Medical Sciences, 26(10):1131-1143. https://doi.org/10.22038/IJBMS.2023.69824.15197.
Friedman, J. H., Hastie, T., & Tibshirani, R. (2010). Regularization paths for generalized linear models via coordinate descent. Journal of Statistical Software, 33(1), 1–22. https://doi.org/10.18637/jss.v033.i01. 
Ghorbani, H. (2019). Mahalanobis distance and its application for detecting multivariate outliers. Facta Universitatis, Series: Mathematics and Informatics, 583-595. https://doi.org/10.22190/FUMI1903583G.
Gresta F., Avola G., Lombardo G.M., Siracusa L., & Ruberto G. (2009). Analysis of flowering, stigmas yield and qualitative traits of saffron (Crocus sativus L.) as affected by environmental conditions. Scientia Horticulturae, 119 (3): 320-324. https://doi.org/10.1016/j.scienta.2008.08.008
Hastie, T., Tibshirani, R., & Friedman, J. (2009). Elements of Statistical Learning: Data Mining, Inference, and Prediction. Springer
Kaveh, H., & Salari, A. (2018). Study and comparison of saffron quality produced in major centers of production in Khorasan provinces. Saffron Agronomy and Technology, 6(2), 209-218. (In Persian with English abstract) https://doi: 10.22048/jsat.2017.59510.1184.
Khan, F., Siddique, A.B., Shabala, S., Zhou, M., & Zhao, C. (2023). Phosphorus plays key roles in regulating plants' physiological responses to abiotic stresses. Plants, 12(15): 2861. https://doi.org/10.3390/plants12152861.
Koocheki A., Seyyedi S.M. (2019). Mother corm origin and planting depth affect physiological responses in saffron (Crocus sativus L.) under controlled freezing conditions. Industrial Crops and Products, 138, 111468. https://doi.org/10.1016/j.indcrop.2019.111468.
Koocheki, A., & Sabet Teimouri, M. (2014). Effect of age of farm, corm size and manure fertilizer treatments on morphological criteria of Saffron (Crocus sativus L.) under Mashhad conditions. Applied Field Crops Research, 27(105). 148-157. https://doi.org/10.22092/aj.2014.103365.
Kothari, D., Thakur, M., Joshi, R., Kumar, A., &   Kumar, R. (2021). Agro-climatic suitability evaluation for saffron production in areas of Western Himalaya. Frontiers in Plant Science, 12:657819. https://doi.org/10.3389/fpls.2021.657819.
Lozano P., Delgado D., Gómez D., Rubio M., & Iborra J.L. (2000). A non-destructive method to determine the safranal content of saffron (Crocus sativus L.) by supercritical carbon dioxide extraction combined with high-performance liquid chromatography and gas chromatography. Journal of Biochem Biophys Methods, 43(1-3):367-78. https://doi.org/10.1016/s0165-022x(00)00090-7.
Mardani Asl, S.A., Movahhedi Dehnavi, M., Salehi, A., &   Yadavi, A. (2018). Effect of corm weight and planting density on saffron (Crocus sativus L.) yield between apple trees in Firouzabad of Yasouj. Journal of Saffron Research, 6(1), 89-102. (In Persian with English abstract) https://doi.org/10.22077/jsr.2017.823.1034.
Mohammadkhani, F., Pouryousef, M., & Yousefi, A.R. (2023). Growth and production response in saffron-chickpea intercropping under different irrigation regimes. Industrial Crops and Products, 193: 116256. https://doi.org/10.1016/j.indcrop.2023.116256.
Muche M., Kokeb A., & Molla E. (2015). Assessing the physicochemical properties of soil under different land use types. Journal of Environmental & Analytical Toxicology, 5, 309. https://doi.org/10.4172/2161-0525.1000309.
Nassiri Mahallati, M., Koocheki, A., Amin Ghafouri, A. & Mahluji Rad, M. (2015). Optimizing corm size and density in saffron (Crocus sativus L.) cultivation by central composite design. Saffron Agronomy and Technology, 3(3), 161-177. (In Persian with English abstract) https://doi.org/10.22048/jsat.2015.10386.
Nelson, D.W., & Sommers, L. E. (1996). Total carbon, organic carbon, and organic matter. In Methods of Soil Analysis; Part 3, SSSA Book Series; Sparks, D.L., Page, A.L., Helmke, P.A., Loeppert, R. H., Soltanpour, P.N., Tabatabai, M. A., Johnston, C. T., Sumner, M. E., Eds.; Madison: Indianapolis, IN, USA, 1996; pp. 961–1010.
Olsen, S. R. (1954). Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate (No. 939). US Department of Agriculture.
Pirasteh-Anosheh, H., Babaie-Zarch, M. J., Nasrabadi, M., Parnian, A., Alavi-Siney, S. M., Beyrami, H., Kaveh, H., Hashemi, S. E., Durrer, U., McDonald, K., & Race, M. (2023). Climate and management factors influence saffron yield in different environments. Agrosystems, Geosciences & Environment, 6, e20418. https://doi.org/10.1002/agg2.20418 .
Poudyal, S., Owen, J. S., Sharkey, T. D., Fernandez, R. T., & Cregg, B. (2020). Phosphorus requirement for biomass accumulation is higher compared to photosynthetic biochemistry for three ornamental shrubs. Scientia Horticulturae, 275, 109719. https://doi.org/10.1016/j.scienta.2020.109719.
Riyahi, R., Mirdamadi, S., Farrajollah Hosseini, S., & Omidi Najafabadi, M. (2023). Investigating the role of saffron business clusters in rural development (Case Study: South Khorasan Province). Village and Development, 25(4), 213-231. https://doi.org/10.30490/rvt.2023.357120.1432.
Sepaskhah, A., & Kamgar-Haghighi, A. (2012). Saffron Irrigation Regime. International Journal of Plant Production, 3(1), 1-16. https://doi.org/10.22069/ijpp.2012.627.  
Shahnoushi N., Abolhassani L., Kavakebi V., Reed M., & Saghaian S. (2020). Economic analysis of saffron production. Saffron: Science, Technology and Health. pp. 337-356. https://doi.org/10.1016/B978-0-12-818638-1.00021-6
Tibshirani, R. (1996). Regression shrinkage and selection via the lasso. Journal of the Royal Statistical Society: Series B, 58(1), 267–288.
Walkley, A. J., & Black, I. A. (1934) Estimation of soil organic carbon by the chromic acid titration method. Soil Science, 37, 29–38.
Wang Z., Li X., Xu J., Yang Z., & Zhang Y. (2021). Effects of ambient temperature on flower initiation and flowering in saffron (Crocus sativus L.). Scientia Horticulturae. 279, 109859. https://doi.org/10.1016/j.scienta.2020.109859.
Wang, X.J., Jia, Zh. K., Liang, L.Y., & Kang, Sh. Zh. (2013). Effect of manure management on the temporal variations of dryland soil moisture and water use efficiency of Maize. Journal of Agricultural Science and Technology, 15, 1293-1304.
Willmott, C.J. (1981). On the validation of models. Physical Geography, 2(2), 184–194.
Ziaei, S.M., Feizi, H., Khashei Siuki, A. & Sahabi, H. (2024). Yield and quality of saffron (Crocus sativus L.) in response to priming treatments and water deficit. Italian Journal of Agronomy. 19(3): 100020. https://doi.org/10.1016/j.ijagro.2024.100020.
Zou, H., & Hastie, T. (2005). Regularization and variable selection via the elastic net. Journal of the Royal Statistical Society Series B: Statistical Methodology, 67(2): 301–320. https://doi.org/10.1111/j.1467-9868.2005.00503.x.  
 
 
 

Home

Submit Manuscript

Reviewers

Contact Us