Reference values and cultivar-induced differences in the evaluation of apple flower analysis

Abstract

This study was conducted to investigate the possible use of flower analyses in assessing the nutritional status of apple orchards at the initiation of vegetation. In successive years, samples were taken from 150 orchards at the initiation of bloom for flowers and at seven different time points covering the timeframe between 14 and 98 days after full-bloom for leaves. When the flower nutrient contents were ordered from lowest to highest, the lower and upper percentage quartile was accepted as the reference value for each nutrient and as the cutoff for nutrient deficiency or excess. Reference values were 3.33–3.98% N, 0.46–0.54% P, 2.10–2.47% K, 0.39–0.51% Ca, 0.25–0.31% Mg, 67–110 ppm Fe, 35–65 ppm Cu, 20–31 ppm Mn, 37–50 ppm Zn and 55–79 ppm B. Correlations between nutrient contents of the flowers and leaves sampled at all time points were also investigated. The presence of significant correlations showed that flower analysis can be used to determine the nutritional status of apples. Positive outcomes were observed for P, Mg, Mn and B. In addition, cultivar-induced differences were also observed in flower for Ca, Mg, Fe, Mn, Zn and B.