VARIATION IN FOLIAR MICRONUTRIENT CONCENTRATIONS AMONG FIVE SELECTED LEUCOSPERMUM GENOTYPES

The study was carried out during two years in six commercial protea plantations with Leucospermum cultivars 'Scarlet Ribbon', 'High Gold', 'Veldfire', 'Sunrise' and Leucospermum patersonii species located in eight municipalities of La Palma island (Canary Islands). Distribution and behaviour of foliar nutrients Cu, Fe, Mn and Zn across time were studied. Nutritional needs varied in some cases among cultivars and species. Detected levels of Fe and Zn were lower than those previously published. Usually, Cu values and those of Zn were higher at the beginning of the development cycle than at the end of it. The opposite was observed with Fe and Mn. Leucospermum patersonii species showed the highest Fe and Zn concentrations, which suggests a greater requirement of this species for these nutrients. Cultivar 'High Gold' showed the highest concentrations of Cu and 'Scarlet Ribbon' those of Mn. A general stability of micronutrient concentrations was observed in the September, November and/or January samplings, so that November is recommended for taking samples for current foliar analysis. Foliar ranges for the studied nutrients are suggested for these different cultivars and species.