Effect of irrigation levels and high corm density on growth and phosphorus uptake of of daughter corms of saffron (Crocus sativus L.)

Effect of irrigation levels and high corm density on growth and phosphorus uptake of daughter corms of saffron (Crocus sativus L.) was studied under a field experiment as split-plot arrangement in complete randomized block design with three replications at Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran, during 2012 and 2013. The irrigation levels were applied based on saffron water requirement (50, 70 and 100%) and high corm density (50, 100, 200 and 300 corms.m-2) were assigned and randomized in the main and sub plots, respectively. Results showed that the lowest corm number, yield and phosphorus content of corms (178.67, 450.11 and 0.65 g.m-2, respectively) were observed by sowing 50 daughter corms per m2 + 50% irrigation. In addition, the highest corm number, yield and phosphorus content of corm 806.67, 2709.18 and 3.38 g. m-2, respectively) were obtained by sowing 300 daughter corms per m2 + 100% irrigation. In the first year, flower characteristics of saffron was not affected by 50% irrigation. However, in the second year, flower number, fresh flower and dry stigma yields significantly decreased by supplying 50% water requirement of saffron (by 19, 28 and 22%, respectively) as compared to control (100% water requirement). Considering the economic value of irrigation water in arid and semi-arid regions of Iran, the irrigation scheduling based on 75% crop water requirement may be reasonable.