Alternativas para adubação de porta-enxertos de abacateiro 'quintal' e seu efeito no pegamento de enxertia

Abstract

The avocado is a fruit of high expression in Brazilian fruit scenario. One of the factors that limit the rational expansion of this fruit in Brazil is the difficulty of obtaining high quality seedlings. This study aimed to-evaluate the formation of Quintal avocado rootstocks, under greenhouse conditions, with use of slow-release fertilizer and nutrient solution with different doses of NPK. The experiment was carried out at the Division Fruit Crops of the Department of Agriculture/Universidade Federal de Lavras-MG, from May to October 2009. The experimental design was in randomized blocks in factorial scheme 2X4 (two sources and four doses of fertilizers) with an additional treatment (control) with four replicates, and the experimental plot was constituted by ten plants. Plants were grafted, using cultivar Fortuna as scion. Treatments were consisted by four doses of slow-release fertilizer 15-10-10 (NPK) at a ratio of 4, 8, 16 and 24 kg m-3 of soil used as substrate, and four doses of nutrient solution, where NPK was applied in a mixture of urea, potassium nitrate, and phosphate monoammonium in the same proportion as the other fertilizer. The rootstock characteristics evaluated were: height (cm), diameter (mm), dry leaves, roots and stems (g), N, P and K in leaves (mg kg1 ) and grafting success rate (%). It was noticed a significant interaction among factors for height, diameter, leaves, roots and stems dry, and grafting success rate characteristics. The use of slow-release fertilizer promoted greater growth and development of Quintal cultivar avocado seedlings when compared to nutrient solution. Doses above 8 kg m-3 of slow-release fertilizer and nutrient solution were not satisfactory in the formation of ‘Quintal’ avocado seedlings.