1a. Objectives (from AD-416)
The project addresses the Specialty Crop Research Initiative (SCRI) stated need for "Developing innovative breeding systems that improve the speed and flexibility to deliver unique cultivars to meet future challenges". The proposed "FasTrack" will be an advanced fruit tree breeding system that uses transgenic early and continually flowering trees to overcome the limitations of juvenility and dormancy, producing the first generation in one year versus the normal three to seven years. Unlike conventional breeding, "FasTrack" crosses will be done in the greenhouse, and only the non-transgenic individuals from segregating populations will be released to the field. We propose to implement "FasTrack" using a transdisciplinary, whole systems approach to address the short- and long-term challenges facing the $200 million dollar California dried plum industry. Two industry specified traits, Plum Pox Virus (PPV) resistance and high sugar content, will be rapidly incorporated into industry standard germplasm. Molecular markers will be used to further improve the efficiency of the "FasTrack" rapid backcross breeding scheme. The economics of "FasTrack" breeding versus conventional breeding will be compared in two participating plum breeding programs. The project progress will be monitored by an advisory board and will be directly communicated to Prunus breeders, industry representatives, and scientists. Through consultation with domestic and foreign regulatory agencies, a comprehensive plan will be developed to determine if "FasTrack" progeny are exempt from regulation and accepted as standard varieties. Environmental and consumer-oriented NGOs will be consulted to address the public acceptance of "FasTrack" technology and pave the way for future commercial releases.
1b. Approach (from AD-416)
The "FasTrack" breeding project proposes to deliver an advanced biotechnology to an existing industry supported plum cultivar development program. "FasTrack" breeding technology will be developed to specifically meet the needs of the California dried plum industry by integrating the system with the major California dried plum industry's breeding program and targeting traits highly desired as test cases. The probability of success of this project is highly based on the long-term expertise and experience of the project investigators in plum breeding and transgenic technology of plum. This will ensure that the benefits of "FasTrack" technology are realized and lead to long-term commitments by the California dried plum industry, while at the same time, strengthening the plum "FasTrack" system’s role as a model for other tree fruit industries to follow.
3. Progress Report
'FasTrack' breeding is a system to create a generation every year. In order to optimize the diversity, follow each parent's contribution, and follow specific traits, a series of molecular markers is necessary to mark each group. Material for creating and testing molecular markers for the high sugar trait was collected from a cross of high sugar germplasm, as well as from other high sugar germplasm from the California collection. Leaves from 'Honeysweet' plum, which carries the Plum pox virus (PPV) resistance, were also collected. Towards this end, SSR markers from other Prunus systems were tested on parental lines to look for polymorphisms. Seven markers were found and were used to screen the California germplasm with high sugar profiles as well as the 'FasTrack' material. Additional SNP markers were isolated from the comparison of the 'Improved French' and the 'HoneySweet' whole genomes, and developed into marker systems to test on the 'FasTrack' crosses of 'HoneySweet' and 'Improved French' related germplasm. The ADODR has monitored activities through emails, meetings, and calls.