EFFECTS OF DENSITY, RECTANGULARITY AND ROW ORIENTATION ON APPLE-TREES, MEASURED IN A MULTIVARIATED EXPERIMENTAL-DESIGN

A single-plant-plot design was found very suitable for a study of growth and yield effect of tree density, rectangularity and row orientation on a wide range of intra and inter-row planting-distances. Densities from about 250 to 40 000 trees per hectare were studied in 2 apple cultivars on 2 weak-growing rootstocks over a period of 8 years. On unpruned trees a maximum yield of 80 tons per hectare of 'James Grieve' and about 95 tons of 'Spartan' was recorded. At the highest densities these yields were reached 2-3 years after planting. As early as the second to third year the growth was restricted at densities over about 1000 trees per hectare. A higher yield per tree at medium densities than at lower densities for the first fruiting-years is supposed to be an effect of growth resulting in earlier fruiting. A high rate of rectangularity reduced the yield only on densities of 1200-1550 trees per hectare. The lack of a significant effect on lower and higher densities is discussed. The growth and yield of rows oriented North-South were 17% higher than of those oriented East-West. © 1979.