Evaluation of Pyrus Interspecific Hybrids in Arizona from 2001 – 2004

Abstract

Pyrus calleryana are widely used in landscapes in regions where they are adapted, however there are many species of Pyrus that have not been explored for their potential use in landscapes, particularly in hot, arid climates. The Landscape Plant Development Center in Chanhassen, Minnesota has started a program to develop small statured pear trees for landscape use in different climates. This project in Arizona was initiated in conjunction with the Landscape Plant Development Center with the objective to test second generation hybrid Pyrus species for adaptation to the arid climate of the Southwest. Fifty trees were planted in Sierra Vista and 30 trees were planted in Tucson, Arizona, in March 2001. Plant growth, survival, and aesthetic characteristics were observed until fall 2004. Out of thirty trees tested at the Tucson site, one tree from the cross of Calleryana 'Chanticleer' x eleagrifolia appeared to be well adapted to the climate of the mid-elevation desert based on growth, branch structure and foliage health. Pyrus trees performed better in the cooler climate in Sierra Vista compared to Tucson. However, Texas root rot at the site decimated 40 of the 50 trees by the end of the fourth growing season. The aesthetically most pleasing tree at the Sierra Vista site was a cross between fauriei x betulifolia. This provenance was represented with 17 trees in Sierra Vista, nine of which showed good performance by October 2004. Trees from this provenance seem to be well adapted to the arid climate of the higher elevation desert and appear to have a number of desirable characteristics for urban landscapes.