Mineral nutrition of artichoke stock plants grown in soilless culture

Artichoke plants of 'Romanesco' type [Cynara cardunculus L. var. scolymus (L.) Fiori - cultivar C-3] were grown as stock plants under greenhouse conditions for producing disease-free propagation material (offshoots). According to the Systematic Variation method (SV), six nutrient solutions with different proportions of NO3, SO42-, H2PO4-, K+, Ca2+ and Mg2+ were applied in a randomized complete block design with five replicates. The SV method permitted to calculate the macronutrient proportions, which optimize growth of stock plants (dry weight and leaf number), and offshoot production. In a second experiment, the optimal nutrient formula for offshoot production obtained using the 2001 experiment data was applied at different concentrations (12, 24, 36, 48 and 60 meq/L) in a randomized complete block design with five replicates. The results showed that the highest offshoot production occurred at a macronutrient concentration of 50.2 meq/L.