Changes of some growth indices and yield of saffron (Crocus sativus L.) in different altitudes

Saffron can be cultivated in many regions of the world with different climates. But the best climate for growing saffron is the Mediterranean climate with its warm and dry summers. The present study was conducted to evaluate some indicators of saffron growth in 2019-2020 in four region with different altitudes above sea level in Sari, Iran. These regions include Sari plain (level with sea level), Sarkat (350 meters above sea level), Reskat (900 meters above sea level) and Margav (1350 meters above sea level). These experiments were performed in a randomized complete block design with three replications. The treatment was includes corm size in three weight groups: small (4±2 g), medium (10±2 g) and large (15±2 g) and Measured traits include leaf area index, cumulative dry matter, growth rate, relative growth rate and saffron yield. The results showed that the trend of saffron leaf area development in all studied regions has a non-linear trend and follows a logistic-peak function. Based on the results, a significant difference was observed between the leaf area development trend among different sizes of mother corm in all regions and the trend of leaf area index changes during the growing season was higher for larger corms than for smaller corms. The trend of changes in dry matter accumulation also had a sigmoidal trend in all experiment region. Total dry matter changes were higher for larger corms. Although the trend of changes in crop growth rate in higher altitude region was lower; But the rate of growth rate fluctuation or in other words the difference between the minimum and maximum growth rate during the season in the two higher regions was less than the lower regions. The growth trend of saffron in four regions showed that it grows during the season in region with higher altitudes above sea level and following more vegetative growth and more dry matter allocation to the storage organ, larger corm is produced and the potential to increase the yield of dried saffron flowers and stigmas will increase next year.