Effect of phosphorous and nitrogen on vegetative growth and production of daughter corms of saffron

Saffron (Crocus sativus) is known as one of the most valuable spice and medicinal plant worldwide and especially in Iran. Despite the high importance of this strategic plant, there are only few studies about the role of nutrients on saffron growth. Therefore, the objective of this study was to investigate the effect of different levels of phosphorus and nitrogen on the uptake of these nutrients, and also production of saffron daughter corms. A pot experiment was conducted as a completely randomized design with factorial arrangement under open door conditions. Different levels of phosphorus (0, 35 and 70 kg.ha-1) and nitrogen (0, 50 and 100 kg.ha-1) with three replications were treated. Also, two harvests were performed to cover two different growth periods. After each harvest, fresh and dry weight of corm and leaf, the number of daughter corms and the concentration of phosphorus and nitrogen in the corm and leaf were determined. The results of this study showed that by increasing P, the fresh weight of saffron corms was increased and the number of corms was decreased. While an inverse trend was observed with nitrogen application. The weight of corms and leaves were increased over time. Uptake and concentration of phosphorus and nitrogen in the second harvest of saffron were increased in corm, whilst they were declined in leaves.