Differential response of mango varieties to boron

The behavior of four mango varieties (Haden 2H, Tommy Atkins, Winter and Van Dyke) grafted on three different rootstocks (Carabao, Coquinho and Manga D'agua) in relation to boron, was investigated under open field cultivation, at Votuporanga, State of Sao Paulo, Brazil. Borax, at the rate of 300 g per plant was applied to the soil in 1995 and 100 g the following years, to three experimental blocks, leaving three blocks without boron, as checks. The rootstocks showed small differences in response to boron. The crown varieties however showed striking differences in response to boron. The Winter cultivar was the least sensitive, Tommy Atkins, was intermediate and Haden 2H and Van Dyke were very sensitive to boron. The borax application did not alter the yield of Winter, doubled the yield of Tommy Atkins and increased more than five limes the yield of Haden 2H and Van Dyke. The low yield of Van Dyke and Haden 2H, without boron application, was due to excessive drop of young fruits. The average of boron content in the medium leaves without boron application, ranged from 7.6 to 10.0 mg/kg and in the blocks which received boron were from 23.9 to 29.9 mg/kg. It was concluded that the boron requirement of mango varieties used as crown is quite variable.