Plum crazy: Rediscovering our lost Prunus resources

Recent utilization of genetic resources of peach [Prunus persica (L.) Batsc h] and Japanese plum (P. salicina Lindl. and hybrids) has been limited in t he United States compared with that of many crops. Difficulties in collecti on, importation, and quarantine throughput have limited the germplasm avail able. Prunus is more difficult to preserve because more space is needed tha n for small fruit crops, and the shorter life of tries relative to other tr ee crops because of disease and insect problems. Lack of suitable rootstock s has also reduced tree life. The trend toward fewer breeding programs, mos t of which emphasize "short-term" (long-term compared to most crops) commer cial cultivar development to meet immediate industry needs, has also contri buted to reduced use of exotic material. Probably all modern commercial peaches grown in the United States are relat ed to 'Chinese Cling', a peach imported from China over 100 years ago (Myer s et al., 1989). More recently imported germplasm has not significantly imp acted modern production. The relatively few available accessions of wild pe ach relatives have been useful primarily in development of peach rootstocks . In contrast, a large shipping plum industry in California has been develo ped based on plum cultivars imported 100 years ago from Japan and on hybrid s of those plums with native species. Native American germplasm has unreali zed potential to help solve current plum problems and stone fruit rootstock problems. However, few resources are devoted to this effort. This germplas m will be discussed in more detail in relation to the U.S. Dept. of Agricul ture (USDA)-Agricultural Research Service (ARS) breeding program at Byron, Ga.