1a. Objectives (from AD-416)
To develop and test a fruit tree rapid-cycling breeding program and to develop novel plum breeding germplasm.
1b. Approach (from AD-416)
Early flowering transgenes will be utilized to develop a rapid-cycling breeding system to dramatically shorten plum generation time. Using this approach, improved plum germplasm with Plum Pox Virus (PPV) resistance and high sugar control will be developed. "Specialty Crops Research Initiative Proposal"
3. Progress Report
Four early flowering plum lines were characterized in terms of growth, flowering and fruit production. These lines were multiplied and, along with other early flowering lines, used as parents in two hybridization schemes: 1) crosses with 'HoneySweet' plum for the transfer of the Plum pox virus (PPV) resistance transgene into California industry-adapted germplasm for the development of new PPV resistant plum varieties useful for the California industry and 2) crosses with high sugar content plum germplasm for the development of new California-adapted plum cultivars with varying combinations of sugars for improved flavor and health benefits. A large number of 'HoneySweet' progeny were obtained and these, upon flowering, will be crossed with selected California varieties. A moderate number of progeny from the high sugar crosses were obtained. Early flowering lines planted in the field under an APHIS permit flowered in the spring (April) with standard plums and continued flowering into the early summer (June). Fruit from cross pollinations of these plums with 'HoneySweet' will be used to compare fruit growth and quality of early flowering clones in the greenhouse and field, and as additional sources of seedlings. Members of the research team met with the California Dried Plum Board and presented a project progress report. A publicly accessible 'FasTrack' breeding website was initiated with information concerning the project and its progress.