Department of Plant Sciences

Mineral concentrations (DW% sampled over three years) of apple plant tissues were significantly (P = 0.05) affected by the kind of rootstock, rather than the kind of scions (Golden Delicious, and Red Gala). The effect of rootstock genotypes (M.9, MM.106, MM.111, and seedling rootstocks) on the major minerals (N, K, Mg, Ca, Fe, and Mn) was significant. Leaf and fruit tissue analysis showed that different rootstocks had different mineral uptake efficiencies throughout the season. Trees grafted on seedling rootstock were among the highest in leaf Ca and K. Whereas, those on M.9 rootstock were the most efficient rootstocks in N, Mn, and Fe uptakes. Consequently, M.9 was most efficient in N, and microelement deficiencies. MM.106, was the highest efficient rootstocks in P uptakes. M.9 was the lowest minerals (K, Ca) uptakes throughout the season regardless of the amounts of minerals in their fruits. The highest amount of P leaf concentration (DW%) was recorded in trees grafted on MM.106 rootstock. Effect of rootstock on fruit mineral concentration was significant. The highest Ca-fruit concentration was recorded in cultivars grafted on seedling rootstock. The N/Ca, K/Ca, and (Mg+K)/Ca ratios of apple fruits were influenced by rootstock rather than scion. Golden Delicious/M.9 trees produced the highest yield efficiency (6.5 kg tree-1 m-3), while, Red Gala/seedling produced the lowest (4.8 kg tree-1 m-3) yield efficiency over three years.