OREGON M.N. Westwood, A.N. Roberts January 1965 AND Department of Horticulture ORNAMENTAL Vol. 8, Issue 1 Oregon State University NURSERY DIGEST Pages1, 2 Corvallis, OR

QUINCE ROOTSTOCK USED FOR DWARF PEARS

The quince (Cydonia oblonga) has been used for centuries as a rootstock for pear. Such stocks produce dwarf trees which are earlier bearing (with some varieties) than standard trees. The fruit from dwarf trees may mature a bit early, but it is of good quality.

For the past eight years, quince rootstock studies have been carried out at the Oregon Agricultural Experiment Station to determine varietal compatibility, growth control, effect of interstocks, and resistance to decline.

Decline

East Malling quince A and Lepage Series C Provence quince appear to be resistant to decline. Testing on Provence is limited to four seasons, while that for quince A covers eight years. Some unnamed Angers clones or seedlings are resistant to decline and some are not. Thus nurseries should not propagate unknown clones of quince which have not been tested for decline resistance.

Compatibility

Some pear varieties are not compatible when worked directly on quince. In such cases, a 6-inch compatibility bridge (interstock) is worked between the quince and the scion variety. For many years, Hardy has been used for this purpose, but Old Home has also been used. Both of these cultivars were compared in our tests to determine which was the best interstock.

Our results indicate that Old Home is a far better bridging interstock than Hardy for Bartlett scions. In a high-density hedgerow (720 trees/acre) eight-year-old trees with Hardy interstocks produced only 7.2 tons of fruit per acre, compared with 13.7 tons per acre for trees with Old Home interstocks.

Comice is compatible with several kinds of quince and has produced more fruit when worked direct than when an interstock was used.

Anjou is compatible with EM quince A and Provence, but is weak on some types of Angers.

OP-9 Bartlett in preliminary testing appears compatible with Provence quince but makes stronger unions with an Old Home interstock.

The following table indicates the compatibilities of several pear varieties on quince

Compatible Incompatible East Mailing Quince A Anjou Bartlett Cornice Bosc Old Home Seckel Hardy Winter Nelis Packham's Triumph Eldorado* Gorham Clapp's Favorite Flemish Beauty Forelle Maxine Farmingdale

*Only preliminary testing done.

Our evidence indicates that Provence (Series C) quince has about the same compatibility as EM quince A, but trees on Provence are somewhat larger.

The tendency of a variety to overgrow quince at the union is not related to incompatibility but is merely an expression of differences in growth rate of the two components. For example, Comice greatly overgrows all stocks on which it is worked, even though it is compatible with all that have been tried.

Soils for quince

Quince root does best in an open, well-drained soil. In heavy, moderately wet soils, half of the trees may die the first year. In very wet, poorly drained soils, all of them will die.

Pears on quince root are susceptible to lime-induced chlorosis and thus should not be planted in calcareous soils.

Dwarfing vs. nurse-rooting

Self-rooted Old Home is vigorous and resistant to pear decline. One method of obtaining varieties on Old Home root is to graft Old Home on quince and plant with the union 2 to 4 inches below the ground line. The quince nurse-root keeps the tree going until the Old Home stem is rooted. Such trees will eventually be large and vigorous and entirely on Old Home roots. If this is to be done properly, nurserymen should work the Old Home quite low on the quince (within 4 inches of the ground) so that the trees need not be planted excessively deep in the orchard to get the Old Home portion under ground.

If, however, dwarf trees are desired, the Old Home should be worked 8 to 10 inches high on the quince; so that, when planted in the orchard, the union will be well above ground.

Oregon Ornamental and Nursery Digest was published from 1957 to 1975 by the Agricultural Experiment Station, Oregon State University, Corvallis.

Pesticide Use - Due to constantly changing laws and regulations, no liability for the suggested use of chemicals in this reprint is assumed. Pesticides should be applied according to label directions on the pesticide container.

Permission to Reprint material appearing in the Oregon Ornamental and Nursery Digest is granted with the request that you credit the source: Oregon Ornamental and Nursery Digest, date, volume, issue, page numbers. Do not excerpt or reprint in such a manner as to imply the author's endorsement or criticism of a product or concept.

Nondiscrimination - The information in the Oregon Ornamental and Nursery Digest is provided with the understanding that no discrimination is intended and that listing of commercial products implies no endorsement by the authors. Criticism of products or equipment is neither intended nor implied.