Studying nutritional efficiency of grafted coffee plants is important for the selection of graft/ rootstock combinations, aiming to achieve better plant development and yield. The objective of this work was to evaluate the genetic differences for B, Zn, Cu and Mn absorption and utilization efficiencies of grafted coffee seedlings. The experiment was conducted with seedlings planted in 20 L pots with a substrate consisting of soil, sand, and manure in the proportion of 3:1:1, in which they kept for 18 months, until harvest. Four genotypes of Coffea arabica L. were used as grafts: cultivars Catuaí Vermelho IAC 15 ('Catuaí 15) and Oeiras MG 6851 ('Oeiras'), and hybrids H419-10-3-4-4 ('H419') and H514-5-5-3 ('H514'). All genotypes were obtained from the EPAMIG/UFV breeding program. Five half-sibling progenies of clones of Coffea canephora Pierre ex Froenher cv. Conilon were used as rootstocks: 'ES 21', 'ES 36', 'ES 26', 'ES 23' and 'ES 38, which were obtained from the INCAPER robusta coffee breeding program. The experiment was arranged in a complete randomized design, with 24 treatments and 3 repetitions, using four control plants and 20 grafting combinations. The nutritional efficiency of coffee plants varied according to the graft/rootstock combination. Considering that all combinations promoted dry matter yield decrease when compared with the respective non-grafted plants, cultivar Oeiras MG 6851 was not benefited by any graft. Cultivar Catuaí Vermelho IAC 15 was more efficient in dry matter production and Cu and Mn utilization when combined with conilon rootstocks 'ES 26' and 'ES 23'.
Coffee; grafting; micronutrients; nutrition efficiency
