Developing new prune cultivars for the California dried prune industry

California is a world leader in dried prune production but is almost entirely dependent on the use of a single cultivar, the 'Improved French' prune. This monoclonal situation lends itself to vulnerability to widespread disease, pest outbreaks and annual, statewide variations in yield caused by variable weather conditions that can negatively or positively affect fruit set and/or fruit retention. In addition to the risks of a monoculture system, the entire industry harvests and dehydrates the crop within a few weeks, since the entire crop has a similar developmental pattern. In highly competitive markets, the industry would benefit from the development of new prune cultivars that have cost saving characteristics such as improved tree structure that would require less pruning, improved fruit dry matter content that would decrease drying costs and expanded windows for bloom and harvest. The California prune breeding program at UC Davis has enlarged its germplasm and bred new generations of progeny through traditional horticultural breeding methods since its beginnings in 1985. In addition to expanding periods of bloom that will mitigate against risks of periods of inclement weather during bloom and selecting genotypes that can expand the harvest window, in recent years the program has identified selections with enhanced fruit quality characteristics that increase efficiency and quality of drying and processing. This report will focus on the characteristics of six of the latest selections that are currently being evaluated in advanced grower trials to determine suitability for the commercial California dried prune industry.