Understanding Aphid Resistance in Black Raspberry, Rubus occidentalis

The North American large raspberry aphid (Amphorophora agathonica Hottes) is the primary vector of Black raspberry necrosis virus (BRNV) which causes rapid decline in cultivated black raspberry (Rubus occidentalis L.) plant vigor leading to plant death and therefore poses a great risk to the viability of the Pacific Northwest black raspberry industry. The objective of this study was to understand the genetic architecture of three sources of aphid resistance identified in wild black raspberry germplasm collected from Ontario, Canada (ON), Maine (ME), and Michigan (MI). Linkage maps were constructed from three full-sib black raspberry populations designated ORUS 4304 (ME), ORUS 4305 (ON), and ORUS 4812 (MI) using microsatellite markers and single nucleotide polymorphisms generated with genotyping by sequencing. Preliminary mapping results indicate that all three loci are on the same linkage group, are near each other, and that each locus is unique. Phenotypic data from an additional 17 black raspberry populations with single and combinations of sources of aphid resistance have been collected. DNA-based markers are being developed for each of these sources to use for pyramiding multiple sources of resistance in new breeding material to ultimately provide resistance that will not easily be overcome by the aphids.