Quince rootstocks

Only relatively flat sites are suitable for nurseries. On sloping sites there is a risk of erosion because the soil has to be kept bare. In addition, locations where there is a risk of frost (winter frost and late frost) should not be used as nurseries, especially for the propagation of stone fruit and pears on quince rootstocks. Nurseries should preferably be set up on medium-heavy soils. Humus-rich, loamy sand soils or sandy loam soils are especially favourable. A soil index well above 50 is advisable for nurseries. 

Soil requirements are similar to those for apples. Pears, especially on a quince rootstock, suffer from chlorosis when the pH is high. 

Sudden changes in temperature of this type cause very severe damage to the wood and flower buds of sensitive varieties (e.g. Gala, Elstar, Jonagold, Braeburn) as well as root damage to rootstocks (e.g. quince and M9). It has been found that sunny slopes, hollows and sites with a high groundwater level (moist, cold soil) are most at risk in this respect. 

In many cases cultivated soils have compacted areas which can severely impair tree growth. Compaction in soil may be due to factors associated with soil formation or geology, or it may have been caused by mechanical pressure from machinery or by deposits by transport and ground-levelling vehicles. If the soil is compacted it is absolutely essential to loosen the subsoil (e.g. by trenching or deep cultivation) before a new orchard is set up. Dwarfing rootstocks for apples and pears (M9, M27, quince C), elder and small fruit trees are particularly sensitive to soil compaction. 

On suitable sites, Quince C is in fact the only rootstock which meets the requirement of high planting densities combined with satisfactory conditions of exposure to light. Unfortunately, because of its sensitivity to frost, this rootstock is often not sufficiently available and is risky in many sites. This applies particularly to growing in the nursery, but also to the first 2 years after planting. As a matter of principle, this rootstock... 

At present we consider that the optimum planting stock is a well-developed, virus-free, 2-year-old tree on a Quince C rootstock. With some cultivars, e.g. Williams Bon Chretien, an interstock is needed. On poorer sites, or when replanting, it may he advisable to use Quince A or Quince Adams. In most cases Quince C should he given preference, however. These trees produce faster and grow less vigorously as a result, so the tree structure is simpler. 

The 2-year-old graft should have 4-6 equal shoots of 40 cm length in 75 cm. These shoots are then used as the framework branches. If Quince A is used as the rootstock, the graft union should not be more than 20 cm above the ground. In the case of Quince C, 2 cm is sufficient, so as to provide better protection against winter frost. 

FARMYARD MANURE. Apply well-rotted farmyard manure in late autumn, winter about 20-30 t/ha. Small fruit and all shallow-rooting rootstocks (M9, M27, quince C for pears) respond particularly well to this treat-... 

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