To examine how boron toxicity affects growth and nutrient composition of several barley and wheat cultivars.

• Several barley and wheat cultivars displaying a broad range of tolerance to boron toxicity were cultured in solution culture at boron concentrations from adequate to toxic.
• Tolerant cultivars developed fewer symptoms, grew better and absorbed less boron than sensitive varieties.
• The supply of boron had no consistent effects on the tissue concentration of macronutrients (K, S, Mg, P, Ca) and trace elements (Cu, zinc, Mn, Fe).
• There appeared to be no interaction between boron and other elements.
• It was concluded that differences between cultivars in tolerance related to the amount of boron absorbed.