A novel technology for speeding the improvement of germplasm and varieties of tree fruits and other long-generation cycle crops. ‘FASTRACK’ BREEDING A TECHNOLOGY FOR THE RAPID IMPROVEMENT OF TREE FRUIT AND OTHER LONG-GENERATION CYCLE SPECIALTY CROPS FRUITING TREES IN ONE YEAR !

THE PROBLEM: Fruit trees like peach, plum, apricot and cherry, need to grow for at least three years and sometimes more than seven years before they flower and fruit. That means for a breeder to improve a trait such as disease resistance, it is necessary to wait 3-7 years to see the results of each cross. Several to many generations are needed to produce an improved variety. In practice it can take anywhere from years or longer to produce a new variety.

The Solution: ‘FASTRACK’ A breeding system that uses a genetically engineered (GE) tree flowering gene that produces generation cycles of one year or less. How does it work? The next few slides will illustrate

STEP 1: The Early, Continual Flowering (ECF) Gene is inserted into a parent plum line through genetic engineering. Genetic Transformation Transgenic tree regeneration ECF inducing gene ready to be inserted into the plum tree ECF gene is inserted into a plum plant ECF plum (the T indicates that it carries the ECF gene) T An early flowering plum parent tree is produced that can flower and fruit within a year.

This early flowering parent is ready to enter into a breeding program to combine traits of interest. Instead of waiting 3-7 years for each generation, a generation can be made every year. Instead of waiting 20 years for each new variety, a new variety can be made in five years.

back cross In each generation the highest quality ECF plums with the highest sugar content are selected and used as parents STEP 2: An example Crossing the ECF line for several generations with high sugar but otherwise poor quality plums to develop sweeter plum varieties. This can be carried out until the breeder has trees with fruit that have a good combination of sweetness, other flavors good size, nice color, etc. X High sugar plum EFC plum T X High sugar or other high quality trait Higher sugar high quality ECF trees ECF Plum TT SELECT Higher sugar, high quality ECF trees as parents for the next generation T SELECT Higher sugar, high quality ECF trees as parents for the next generation

STEP 3: Select the best. There are 4 types of trees to choose from in the last generation: T T High sugar high quality types not GE ECF + High sugar types ECF not desirable sugar and/or fruit type Not desirable sugar and/or fruit type not GE Only the high sugar, high quality, non-ECF (non-GE) types are selected.

Outcome: ‘FasTrack’ Breeding as outlined in this presentation can, in a relatively short time, provide improved tree fruits (in this case high quality, high sugar plums). For example, considering a generation time of 4 years for plum, 3 generations would normally require 16 years. FasTrack breeding would accomplish 3 generations in 5 years! In the end the selected FasTrack bred trees are not genetically engineered. Each tree has the potential to be a new cultivar or an improved type that can be used for continued breeding through conventional means.

Early Flowering plum plants in the greenhouse

Flowers and Fruit at the same time on the same plant !

Six month old early flowering & fruiting ECF plum plants, flowers, and ripe fruit

Early and continuous flowering and fruiting allows ‘FasTrack’ Breeding to be carried out in green- or screen-house

The FasTrack Team: USDA-ARS, Kearneysville, West Virginia Ralph Scorza Tree fruit breeding (classical and genetic engineering) Chinnathambi Srinivasan Genetic engineering of fruit trees Ann Callahan Molecular biology of fruit quality of stone fruits Chris Dardick Molecular biology of fruit quality of stone fruits We are collaborating with colleagues at other institutions: University of California, Davis Ted DeJong Plum breeding, variety development of dried plums Clemson University Albert Abbott Development and testing of molecular markers for fruit trees Pennsylvania State University Jayson Harper Agricultural economics