Dr Gennaro Fazio USDA-ARS Plant Genetics Resources Unit Geneva NY and School of Integrative Plant Sciences Cornell University Leveraging genomic resources to breed a difficult perennial crop: apple rootstocks

ABSTRACT:

Rootstocks are the foundation of a healthy and productive orchard. As such, the choice of a rootstock can influence the productivity and profitability of an orchard in a very significant way. Rootstock performance is highly correlated with the genetic potential of such rootstock to provide anchorage, explore the soil profile, absorb and transfer nutrients to the scion, adapt to pedo-climatic conditions, tolerate extreme weather events, resist or cope with pathogens, propagate efficiently and impart positive architectural properties to the scion – like vigor control and precocity. The inheritance and control of all these desirable characters is quite complex making breeding of rootstocks quite challenging. Recent advances in genomic technologies are allowing more efficient and informed ways of selecting new rootstocks during the breeding process. Furthermore, breaking down complex traits like tree vigor into component traits (hormonal transport, nutrient uptake and transport, root architecture, water use efficiency) and further characterization of the inheritance of these component traits can simplify the understanding of complex traits and improve the breeding process and outcome. In the Geneva® breeding program we have been studying root architecture, nutrient uptake and translocation, and inheritance of gene expression to better characterize breeding populations and select parents and seedlings for the next generation of apple rootstocks. We present data relating to these traits and how they are associated to performance of released and elite stage apple rootstocks.

PDF attached with additional information.