Effect of planting density on fruit quality and leaf elements concentration of apple on rootstock of M26

High-density planting system is one of the effective methods for improving production and profitability of tree orchards. In this research, the effects of four planting densities (1904, 2666, 3137 and 4800 tree/ha) on annual shoot growth, Physicochemical properties of fruit and leaf mineral contents of apple (Malus domestica Borkh cv ‘Granny Smith’) tree grafted on M26 clonal rootstock were studied in randomized complete block design with four treatments and four replications in College of Agriculture and Natural Resources, University of Tehran, during 2009-2010. Based on results, planting density significantly affected some qualitative characteristics such as fruit length, fruit diameter, total soluble solid, fruit dry matter, fruit ash and sun scald, but no significant effect on fruit weight, fruit L/D ratio, TA and tenacity were observed. Planting density significantly affected the leaf N and Fe concentrations. The highest N (1.81 percent) and Cu (39 µg/kg) the lowest Fe of leaves (237 µg/kg) was observed with 1904 tree/ha. Although, planting density had no significant effect on other mineral elements, but with increasing the planting density, leaf P, K, Mg and Mn content increased, but, Ca and Cu decreased. Increasing in N and Fe was associated with a decrease and increase of current seasonal shoot growth, respectively. Likewise, trees with higher crop tend to have more N and less Fe. These results showed that, under Iran climatic condition, with increasing in planting density of apple orchardit can be produced higher fruit crop without decrease in its quality parameters.