Improving the dessert quality of stone fruits

The major postharvest diseases and methods of control are briefly reviewed. Since the application of fungicides is being restricted worldwide, close attention must be given to handling practices that reduce the need for fungicide treatments. These include an initial wash with a hypochlorite solution, the addition of ethanol to hot water and the use of a warm iodine solution. The use of biological control agents has received considerable attention but none has achieved acceptable levels of control. Rapid advances in genomics, proteomics and metabolomics have enabled genes controlling quality traits and to derive molecular markers for others to be identified. Marker production is facilitated by the small genome size of members of the Rosaceae and the lack of major chromosomal rearrangements among species of Prunus. Peach has been selected as the reference species for Prunus and will be the first member of the Rosaceae to have its genome sequenced and a physical map of the genome is nearing completion. A Prunus microarray (PEACH1.0) based on 4806 unigenes is now available. These molecular approaches will allow genetic markers for traits that affect tree and fruit growth, susceptibility to pests and diseases, and dessert and storage qualities to be developed. The major challenge for physiologists is now to determine how to overcome the large variation in fruit composition and hence eating quality that occurs within trees and among batches from the same orchards.