Investigating the Effect of Saffron Plant Age on Its Production in Lorestan Province

Abstract

AbstractSaffron is a very popular medicinal plant and the most expensive spice in the world. It is highly considered in traditional medicine for the treatment of varied diseases. From among Iranian agricultural crops, it is one of the most valuable products. Due to its special characteristics, its production and export can be developed. As the largest producer and exporter of saffron in the world, Iran accounts for more than 90% of global saffron production. In 2018, more than 71% of the global export of saffron belonged to Iran. Lorestan Province is becoming one of the important areas for cultivating this crop due to its natural conditions and farmers’ interest. This study tried to identify the factors affecting the sustainable development of this crop. For this purpose, during the two consecutive years of 2017 and 18, 3 regions in Kuhdasht, Kuhnani, and Khorramabad townships were selected, in which 5 sample farms were chosen based on the field research. The selected farms had a planting history of 1 to 5 years. Several quadrants were established in the farms and the phenological measurements were recorded based on them. The statistics of these farms were collected to determine the required yields. The means and ANOVA comparisons were applied to analyze the results. The studied parameter was farm age from 1 to 5 years in the 3 regions of Kuhdasht, Kuhnani, and Khorramabad townships. In this investigation, saffron flower characteristics and dry weights of stigma were determined simultaneously with daily phenological inspections of the farms. The results in both years revealed that age was the major factor in yield change in all the 3 regions in a way that saffron yield increased with increasing farm age up to 4 years and then decreased. The effects of farm age on saffron flower and stigma yields were statistically significant. It was found that the lowest and highest yields were respectively related to the 1-, 2-, and 5-year-old farms and 3-year-old farms with a peak yield for the 4-year-old farms. During the study of the role of temperature in the two consecutive years, it was observed that the average temperature had been higher in 2017 and thus the flowering duration had decreased. Accordingly, saffron yield in this year compared to 2018 showed a smaller value, which indicated the role of temperature in yield enhancement during the flowering period. Yield differences were significant in the 3 studied regions. The highest and lowest yields were related to Kuhnani and Khorramabad farms, respectively. Keywords: saffron, Lorestan, farm age, yield, comparison of means Introduction:As a very popular medicinal plant, saffron, is the most expensive spice in the world. It is highly regarded in traditional medicine for being used in the treatment of some diseases. Among Iranian agricultural products, it is one of the most valuable plants since its production and export can be expanded based on its special characteristics. Iran is the largest producer and exporter of saffron in the world and accounts for more than 90% of global saffron production. In 2018, more than 71% of the global export of saffron belonged to Iran. Lorestan Province is located in the west of Iran and has more potential for the production of agricultural products due to its environmental conditions, especially climate, when compared to other eastern, southern, and central provinces. In recent decades, farmers in different parts of this province like other provinces have been more interested in cultivating this crop due to the occurrence of drought and lack of water for agriculture on the one hand and its valuable characteristics on the other hand. Therefore, this province is becoming one of the important areas for farming saffron because of the dominating natural conditions and farmers’ increasing interest in its cultivation. Methodology:This research was conducted in the 3 townships of Kuhdasht, Kuhnani, and Khorramabad in Lorestan Province through field and laboratory methods in 2017 and 2018. Aphenological monitoring site was created in the vicinity of synoptic meteorological stations located in the mentioned townships upon the recommendation of the Agricultural Research Center of the province and the farmers, who had grown saffron bulbs on their farms at the first year in 2013, 2014, 2015, and 2016 and whose plants were still continuing their biological activities. They were invited to cooperate with the researcher at the time of dormancy of their plants or corms in mid-spring (late May) in 2017. Also, another farm, on which saffron plant was to be cultivated in 2017, was planned to be equipped with the mentioned monitoring site. In the middle of May,2018, the farmers removed the saffron corms or bulbs planted on their farms in 2013 for sale and subsequent crop rotation. To replace any farms excluded from the research, a new farm was designated in the selected area in each township and the monitoring was continued. In these farms, the cultivated plants, which had lived from 1 to 5 years, were examined in terms of their phenological stages during the two years of monitoring. In the selected farms, they were divided into equal parts and a code was given to each part. Then, from among the codes, 3 codes were randomly selected for creating a quadrant. Monitoring of the phenological phases was performed based on the BBCH coding system at the same time as recording the relevant weather conditions. In this way, 15 quadrants were created, in which the plants aging 1-5 years could be monitored. Monitoring was continued on the same farms in the second year as well. Discussion:In both years, the results revealed that age was the most important factor in yield change in all the 3 regions. With the increasing ages of the farms up to 4 years, saffron yield showed an upward trend and then decreased. Its flower and stigma yields were low during the first years of cultivation in all the 3 study regions in the two consecutive years. With increasing farm age up to 4 years, saffron yield had an upward trend and reached its peak. Then, the flower and stigma productions decreased until 5 years of farm age. The lowest and highest yields were respectively related to the 1-, 2-, and 5-year-old farms and the 3-year-old farms with a peak in the 4th year. Saffron yields were affected by the natural conditions of the regions and farm age. The total Growing Degree-Days (GDDs) were calculated according to the effective and active temperatures and growth period lengths in Kuhdasht, Kuhnani, and Khorramabad townships during the two years of research. In the first year, the plants in the farms of the mentioned townships had 213, 239, and 204 GDDs and 333, 360, and 314 GDDs based on the active and effective temperatures, respectively. These GDDs were achieved within 24, 24, and 22 days, respectively. In the second year, these farms obtained 190, 263, and 186 GDDs and 327, 371, and 306 GDDs based on the mentioned temperatures, respectively. These GDDs were achieved within 26, 27, and 24 days, respectively.Saffron is a cold-loving plant and its activity and growth period start as the weather begins to get relatively cold. During the study on the role of temperature in the two consecutive years, it was observed that the average temperature was higher in 2017, thus reducing flowering duration. Saffron yield showed a lower amount in this year compared to 2018, which indicated the role of temperature in the flowering period. Conclusion:The results of this research demonstrated that age was the major factor in yield change in a way that saffron yield had an upward trend up to 4 years and then decreased with increasing farm age. Also, the highest flower and stigma yields were observed in the 4-year-old farms, while flower yield decreased with increasing the farm age up to 5 years. In addition, increasing farm age caused enhanced dry weights of the corms. In the first years of saffron cultivation, saffron flower and stigma yields were low and saffron yield was augmented as farm age increased up to 4 years, thus reaching its peak. Afterwards, the amounts of flower and stigma productions per unit area lowered with increasing farm age so that the lowest and highest yields were respectively obtained from the 1-, 2-, and 5-year-old farms and the 3-year-old farms with a peak in the 4-year-old farms. Saffron flower and stigma yields were influenced by the natural conditions of the regions and farm age. Based on the data analysis, the differences in the flower and stigma yields in the 3 studied regions were significant. The highest and lowest yields were related to the farms of Kuhnani and Khorramabad townships, respectively. The effects of farm age on saffron flower and stigma yields were significant as well. Analysis of Variance allows checking certainty of the existence of a linear relationship between variables. Since the levels of significance in the mentioned townships were less than 5%, a significant relationship between farm age and saffron yield could be deduced. Comparison of the sums of squares within the groups and outside the groups of the 3 studied regions demonstrated that the sum of squares within the groups had a smaller share in the total dispersion and thus, the assumption that the yields in the regions were the same was rejected. The GDDs in terms of effective and active temperatures and the growth period length were calculated during the two years of research in the townships. According to the calculation results, 213, 239, and 204 GDDs and 333, 360, and 314 GDDs were obtained based on the active and effective temperatures in the farms of Kuhdasht, Kuhnani, and Khorramabad townships in the first year of the plant cultivation, respectively. These GDDs were achieved within 24, 24, and 22 days, respectively. In the second year, the farms of the mentioned townships obtained 190, 236, and 186 GDDs and 327, 371, and 306 GDDs based on the mentioned temperatures, respectively. The GDDs were achieved within 26, 27, and 24 days, respectively.Saffron is a cold-loving plant and its activity and growth period start as the weather begins to get relatively cold. During the study on the role of temperature in the two consecutive years, the average temperature was observed to be higher in 2017, thus alleviating the flowering duration. A lower value of saffron yield was evidenced in this year compared to 2018, which was indicative of the role of temperature in yield enhancement during the flowering period. References- Bazrafshan, O., Ramezani Etedali, H., Gerkani Nezhad Moshizi, Z., & Shamili, M. (2019). Virtual water trade and water footprint accounting of saffron production in Iran. Agricultural Water Management, 213(5) 368-374. https://doi.org/10.1016/j.agwat.2018.10.034- El Hajj, A., Moustafa, S., Oleik, S,. Telj1, V., Taha, N. Chehabeldine, H., & El Tachach, T.(2019). Yield of Saffron (Crocus sativus) under Different Corm Densities. 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International Journal of Plant Production, Vol. 3, 3(1), January, 2009 .ISSN: 1735-6814 (Print), 1735-8043 (Online) .This is a refereed journal and all articles are professionally screened and reviewed.- Fig. 1: Location of the studied cities- Table 1: Geographical characteristics of the study areas- Table 2: Average temperature, average minimum and maximum temperatures, and precipitation in the study areas in 2017-2018- Fig. 2: Graph of average monthly temperatures of the stations in 2017 and 2018- Fig. 3: Graph of average monthly rainfalls of the stations in 2017 and 2018- Fig. 2: Locations of the selected farms by age in the cities of Kuhnani, Kuhdasht, and Khorramabad in 2017-2018- Table 3: Comparison of means in all the 3 study areas in 2017-2018- Table 4: Beginning and ending dates, means of minimum and maximum temperatures, and mean daily temperature during the flowering phase in the study areas in 2017- Table 5: Beginning and ending dates, means of minimum and maximum temperatures, and mean daily temperature during the flowering phase in the study areas in 2018- Table 6: Saffron yield (g/ha) in terms of plant age in the studied areas in 2017-2018- Fig. 5: Diagram of saffron crop yield in the studied areas in 2017- Fig. 6: Diagram of saffron crop yield in the studied areas in 2018

Keywords

• saffron
• lorestan
• farm age
• yield
• comparison of means