Sour cherry breeding at Michigan State University

The sour cherry breeding program at Michigan State University (MSU) was initiated in 1983 to provide growers and processors with varietal alternatives to 'Montmorency'. The objectives of MSU's breeding program are to develop new sour cherry cultivars which are as productive as 'Montmorency', with superior fruit quality and more resistant to cherry leaf spot (Blumeriella jaapii syn. Coccomyces hiemalis). Due to the lengthy U.S. quarantine period for Prunus clonal material, most of the original seedlings are either from open-pollinated seeds collected in Europe or hybrids between 'Montmorency' and 'Schattenmorelle' (syn.'English Morello') as maternal parents with European cultivars as paternal parents. Some of the most promising seedlings in the MSU collection have scarlet flesh color as opposed to the dark red flesh color favored in many European markets. Data on selected cultivars and seedlings plus progress toward breeding cherry leaf spot resistant selections is presented.