Interação porta-enxerto e copa de cajueiro quanto a tolerância ao alumínio

Abstract

The use of aluminum tolerant cashew genotypes (Anacardium occidentale L.) may be an important strategy to increase crop yield in regions with acid soils, low nutrient availability, and high exchangeable aluminum concentrations. The objective of this work was to verify the influence of grafting and the rootstock and scion interaction of cashew genotypes on tolerance to aluminum. Two experiments were carried out at Embrapa, in Fortaleza, Ceará state, Brazil. The first one to evaluate three cashew genotypes (‘CCP 06’, ‘CCP 09’ and ‘CCP 76’) and two types of seedlings (non-grafted and self-grafted); and the second one to evaluate three genotypes as rootstock (‘CCP 06’, ‘CCP 09’ and ‘CCP 76’) and three as scion (‘CCP 76’, ‘Embrapa 51’ and ‘BRS 226’). In both experiments, the plants were grown in the absence and presence of aluminum (30 mg L-1 of Al) in the nutrient solution and with six replicates. Five-liter pots containing washed sand and Hoagland and Arnon solution at 20% macronutrients concentration and 100% micronutrients concentration were used in the experiments. At 110 days after the application of aluminum, the plants were evaluated for height, stem diameter, number of leaves, leaf area, dry matter of aerial part (stem and leaves) and roots system and their ratio. In both experiments, the presence of aluminum in the nutrient solution negatively affected all evaluated variables. With the data obtained it was possible to conclude that the grafted seedlings of dwarf cashew have a higher tolerance to aluminum, in relation to the non-grafted seedlings. The use of the 'CCP 09' cashew genotype as rootstocks and 'CCP 76' and 'Embrapa 51' crowns results in grafted seedlings with greater tolerance to aluminum.