Foliar Nutrient Content of ‘Starkspur Supreme Delicious’ on Nine Clonal Apple Rootstocks

Abstract

The influence of nine apple rootstocks on foliar mineral content was evaluated in Arkansas (AR), Massachusetts (MA), and Ontario (ONT), as part of the NC-140 1980-81 cooperative project. Nutrient content of vegetative leaves was analyzed for differences among rootstocks, locations, and years. Rootstock affected foliar mineral content in some years but differences were small and no rootstock resulted in nutrient levels in a deficiency range. However, in low pH soil of the AR site, the rootstocks MAC.9 and M.27 EMLA had high leaf Mn levels and expressed Mn toxicity. Rootstock did not affect foliar N level when data were averaged across sites but there were significant rootstock differences in ONT and a significant rootstock by year interaction in MA. Site was the greatest source of variation for N and Mg content while sampling year caused the greatest variation for K and Ca. Across all sites, there were no rootstock by year interactions. In AR, sampling year accounted for the greatest percentage of variance in N, P, K, Ca, Mg, and B content while rootstock was the greatest source of variation for Mn content.