Current State of Pear Rootstock Research: Progress and Priorities

The industry has been stagnating due to declining consumption of processed pears and competition from imported pears and other fruits, as reflected in the loss of 10,000 acres, or 15%, since 2000. Two major factors in pear acreage decline are lack of precocity and high cost of production. Existing mature trees are large and widely spaced in orchards, and new trees are slow to bear, which discourages replanting. Close spacing accelerates per acre yields, but trees that are planted more closely tend to overgrow their space because growers must still rely on standard rootstocks. Pears are also extremely labor intensive. The U.S. pear orchard situation is in contrast to European, and to a lesser extent, South American orchards, which successfully utilize the truly dwarfing rootstock quince (Cydonia oblonga Mill.), which has enabled high density plantings and modern training systems. Quince has been found to lack desirable horticultural characteristics for the U.S., e.g. cold hardiness in the Pacific Northwest, long-term vigor and productivity in California, and fire blight tolerance.  Because of the above described scenario, there is broad and deep consensus among all sectors of the U.S. pear industry that achieving efficient (precocious, good yield, fruit size), truly size-controlling rootstocks is imperative for the pear industry to remain competitive nationally and globally.  Most U.S. effort has focused on evaluating commercially available rootstocks from the U.S. or other countries and advanced selections from international sources.  Worldwide, there are at least 12 active breeding programs developing Pyrus rootstocks for European pear, and at least additional nine developing quince rootstocks for pear.  A review of the literature identified 24 evaluation programs.  This presentation will summarize the current breeding and evaluation research, as well as orchard systems trials in the U.S. We will also outline needed basic and applied research, based on experience and stakeholder input from both the Pacific Northwest and California, which have defined a number of basic and applied research and extension needs. Applied research needs include efficient propagation and orchard systems.