Crescimento de cultivares de café em resposta a doses contrastantes de zinco

Abstract

Providing zinc to coffee plants interferes with the growth, development and productivity, and coffee varieties differ in their responses to nutrient availability in soil. This study aimed to identify the differential tolerance of cultivars of Coffea arabica to the lack of Zn, verify how does the partition of zinc contents occur in the plant organs in low and high supply of it and indicate easy measure characteristics of the plant well correlated with tolerance to low zinc supply. Nursery plants of 11 cultivars of C. arabica were grown for eight months in nutritive solution with concentrations of 0,0 and 6,0 mmol L-1 Zn. Stem diameter, plant height, number of primary branches, root volume, leaf number, leaf area and dry weight were determined. There is variability in the response of the coffee cultivars to the supply of Zn, and among the cultivars studied San Ramon, IPR- 102 and Rubi were the most tolerant to the restriction in Zn supply, whereas the ‘São Bernardo’ was the less tolerant to low Zn dose. In adequate or high supply this nutrient accumulates in roots and stems, which can serve as the nutrient reserve organs. In conditions of lack of the nutrient the appical leaves are the preferred accumulation organ. The total dry weight accumulation proved to be the characteristic of greater relative importance in the discrimination of the varieties studied.