Modeling optimal mineral nutrition for hazelnut micropropagation

Micropropagation of hazelnut (Corylus avellana L.) is typically difficult because of the wide variation in response among cultivars. This study was designed to determine the required mineral nutrient concentrations for micropropagation of C. avellana cultivars using a response surface design analysis. Driver and Kuniyuki Walnut (DKW) medium mineral nutrients were separated into five factors: NH4NO3, Ca(NO3)(2), mesos (MgSO4 and KH2PO4), K2SO4, and minor nutrients (boron, copper, manganese, molybdenum, and zinc) ranging from 0.5x to 2x the standard DKW medium concentrations with 33 treatments for use in modeling. Overall quality and shoot length for all cultivars were influenced by ammonium and nitrate nitrogen, mesos and minors. Reduced Ca(NO3)(2) improved multiplication while higher amounts increased shoot length for most cultivars. Uptake of nutrients varied among the cultivars. Calcium and magnesium concentrations were greater in the shoots that grew well compared to poorly-growing and control treatments. All five cultivars showed improved growth on some treatments and the models indicated that shoots grown on an optimized medium would be even better. This model indicates that NH4NO3, Ca(NO3)(2), mesos, and minors all had significant effects on hazelnut growth and multiplication and should be optimized in future experiments.