Characterization of aphid resistance loci in black raspberry (Rubus occidentalis L.)

Authors: Bushakra, Jill; DOSSETT, MICHAEL - Agriculture And Agri-Food Canada; CARTER, KATHERINE - Oregon State University; VINING, KELLY - Oregon State University; Lee, Jana; BRYANT, DOUGLAS - Danforth Plant Science Center; VANBUREN, ROBERT - Michigan State University; Lee, Jungmin; MOCKLER, TODD - Danforth Plant Science Center; Finn, Chad; Bassil, Nahla

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2018
Publication Date: 6/19/2018
Citation: Bushakra, J., Dossett, M., Carter, K., Vining, K., Lee, J.C., Bryant, D., Vanburen, R., Lee, J., Mockler, T., Finn, C.E., Bassil, N.V. 2018. Characterization of aphid resistance loci in black raspberry (Rubus occidentalis L.). Molecular Breeding. 38:83. https://doi.org/10.1007/s11032-018-0839-5.
DOI: https://doi.org/10.1007/s11032-018-0839-5

Interpretive Summary: Viruses carried by aphids cause diseases in black raspberry plant health resulting in a shortened life and poor fruit quality of the infected plantings. New aphid resistant cultivars could increase the longevity of plantings providing growers and processors with consistent fruit production. Recent exploration of the native range of black raspberry identified three sources of aphid resistance. The objectives of this study were to assess segregation of these three sources of aphid resistance in populations with single and combined sources, and develop markers that can identify each source of resistance. All three sources of resistance were found to be associated with each other, and are unique loci. We identified four molecular markers that can be used to detect aphid resistance in progeny derived from parents with aphid resistance from one or more sources. Confirmation of marker association in 16 validation populations identified four markers that could be used to predict resistance.

Technical Abstract: Viruses vectored by the aphid Amphorophora agathonica cause decline in black raspberry plant health resulting in a shortened life and poor fruit quality of the infected plantings. New aphid resistant cultivars could increase the longevity of plantings providing growers and processors with consistent fruit production. Recent exploration of the native range of black raspberry identified three sources of aphid resistance: Ag4 from Ontario (ON), Canada, Ag5 from Maine (ME), and a third source from Michigan (MI) with no formal designation. The objectives of this study were to assess segregation of these three sources of aphid resistance in populations with single and combined sources, and develop markers that can identify each source of resistance. A genetic linkage map constructed for ORUS 4305 placed the ON aphid resistance locus on Rubus linkage group (RLG) 6. Segregation ratios in populations with single and combined sources, and linkage mapping in two populations (ORUS 4304 and ORUS 4812) segregating for the Ag5 and MI sources, respectively, indicated that these three sources of resistance are each conferred by single dominant genes/alleles that are linked on RLG6. Confirmation of marker association in 16 validation populations identified four markers that could be used to predict resistance, however none could distinguish between the ON and MI sources. These four markers may be useful for screening populations to enrich the field-planted progeny for aphid resistance. Fine mapping of the resistance loci is needed to develop functional markers at each of the resistance loci to enable pyramiding and durable aphid resistance.