Effects of apple rootstocks on nutrient concentration in 'Honeycrisp' scions in the early orchard life

Rootstocks not only influence tree growth vigor, branch angle, biennial bearing, and productivity but also have a key role when gathering mineral nutrients from the soil and shuttling them into different sinks in the canopy. Determining tree nutrient requirements is urgently needed for effective management of high value cultivars such as ‘Honeycrisp’, which have high susceptibility to bitter pit. Therefore, identifying rootstocks with better nutrient uptake and more positive effects on fruit quality may represent the most economical long-term solution to many fruit quality problems associated with nutrient imbalances. This study compared the performance of two Malling (M.9T337 and M.26EMLA), one Budagovsky (B.10), eight Geneva^® (G.11, G.202, G.214, G.30, G.41, G.890, G.935, G.969), and four Vineland (V.1, V.5, V.6, V.7) rootstocks with ‘Honeycrisp’ as the scion cultivar. The trial was planted in 2014 as a randomized complete design, with 10 single tree replications. M.9T337 was the most dwarfing rootstock of the trial, followed by G.11 and G.935. G.41 and G.202 were slightly larger, followed by B.10, M.26, G.969, G.214 and V.1. A larger vigorous group comprised V.6 and G.30. V.7, V.5, and G.890 were the most vigorous rootstocks of the trial. The largest fruits (327 g) were on G.11, whereas the smallest were on V.1 (244 g). G.890 had the highest cumulative yield (34 kg tree^‑1), followed by G.30 (30 kg tree^‑1), and G.969 (25 kg tree^‑1). The lowest cumulative yield was observed on G.202 (11 kg tree^‑1) and G.935 (9 kg tree^‑1). N, Mg, Mg/Ca, and N/Ca were highly correlated with bitter pit, and the peel seemed to be more sensitive than flesh. With the highest yield efficiency, crop load and Ca concentration in peel, G.969 seemed to be a promising rootstock for ‘Honeycrisp’ type cultivars. Results from the current study may be used to improve nutrient management for different rootstocks for each nutrient.