Rapid Tree Breed: A Revolutionary Tree Breeding Concept

Today, the US fruit and forest tree industries face unprecedented challenges to growth and sustainability. Problems such as the increased spread of exotic pests and pathogens, global climate change, and others necessitate rapid varietal development, however, trees have inherently long juvenility periods; 3-10 years requiring minimally 20-30 years to complete a varietal selection program. Thus to meet these challenges, we need new technologies that revolutionize the speed and the way tree breeding is typically done. This proposed project directly addresses the core issue of generation time in tree breeding by exploring and developing the concept of rapid cycle breeding technologies where introduction of florigen genes (e.g. FT) through transgene technologies can eliminate the juvenility period and produce early flowering genotypes and rapid cycle breeding lines. More recently, Yamagishi et al 2011 (Plant Mol. Biol. 75:193–204) demonstrated that early flowering can be induced using the Apple Latent Spherical Virus (ALSV) viral vector systems in a number of different plants both trees and herbaceous species. This virus approach has the potential to broaden the use of rapid cycle breeding technologies to any tree species and obviates the requirement for transgenic plant production. For this reason, we propose the following specific objectives for this exploratory project: 1) To test proof of concept for two virus vector systems, ALSV and another broad host range virus Tobacco Rattle Virus (TRV) on two fruit trees species (apricot and peach) and two forest trees (white oak and American chestnut); 2) Explore different flowering control genes for success in induction of early flowering in the different species; 3) Explore and develop a broadly applicable rapid cycle breeding concept for the fruit and forest tree industries.