Effect of Planting Time on Yield of Saffron (Crocus sativus L.) Ecotype in Khash Region

Introduction: Saffron is a subtropical species that thrives in regions characterized by mild winters and, arid summers. While it exhibits considerable cold resistance, the plant's growth cycle occurs during the autumn, winter, and early spring, necessitating favorable and temperate conditions during these seasons. Optimal yields are achieved at temperatures ranging from 35 to 40 ˚C and at elevations between 1300 and 2300 meters above sea level. The time of planting is a critical factor that significantly impacts the yield of agricultural products. Understanding the optimal planting period for saffron in various regions is vital for enhancing both the quantity and quality of the harvest. The suitable planting time for saffron is contingent upon the climatic conditions specific to the planting area. It is important to plant saffron corms while considering the phenological stages of the plant, specifically during the initial stage of dormancy (from June to early July) or during the third stage of dormancy (in September or early October). Establishing the optimal planting date and selecting the most suitable ecotype are essential initial steps in maximizing yield. This study was carried out with these objectives in mind, contributing to the advancement of saffron cultivation in Khash County.
 
Materials and Methods: A research study was carried out to assess the impact of planting date and ecotype on the yield of Saffron (Crocus sativus L.) at the Agricultural and Natural Resources Research Station in the Khash region. The study employed a split-plot design based on a randomized complete block design with three replications. The main plots consisted of four planting times: August 11, August 27, September 11, and September 27, while the sub-plots included three ecotypes: Taybad, Birjand, and Qaen Standard agronomic practices such as irrigation, weed management, and fertilization were implemented. Measurements taken included the fresh and dry weight of the stigma style, the dry weight of the stamen, and the number of flowers. In order to increase the accuracy of the experiment, two initial and final lines and also one meter above and below each plot were considered as margins and four middle lines (about 2.5 square meters) were used to harvest flowers and moved to the laboratory of Agricultural and Natural Resources Research.
 
Results and Discussion: The results from a three-year combined analysis indicated a significant interaction between planting date and ecotype at the 1% level. The highest values recorded for fresh and dry weight of the stigma style, dry weight of the stamen, and flower count were 72.69 kg/ha^-1, 5.82 kg/ha^-1, 4 kg/ha^-1, and 56.96 kg/ha^-1 flowers, respectively, observed at the interaction of the September 11 planting date and the Birjand ecotype. Birjand ecotype exhibited superior fresh and dry weights of stigma and pistil, dry weight of stamens, and flower count compared to the Qaen and Taybad ecotypes. The differing climatic conditions of the regions from which the ecotypes were collected may contribute to the variations in yield and the traits studied in this experiment. Previous studies indicated the time of planting in September is a critical factor that significantly impacts the yield of agricultural products, and enhancing both the quantity and quality of the harvest. The suitable planting date for saffron is contingent upon the climatic conditions specific to the planting area. The Birjand ecotype exhibited superior average dry weight of stigma and pistil, dry weight of stamen, fresh weight yield of stigma and pistil, and a higher number of flowers per square meter compared to other ecotypes.
 
Conclusion: It is recommended that the September 11 planting date and the Birjand ecotype be utilized to enhance the yield and yield components of saffron in the Khash region and similar climatic conditions.