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United States Department of Agriculture

Agricultural Research Service


item Mccord, Pers
item Haynes, Kathleen
item Sosinski, Bryon
item Clough, Mark
item Yencho, G

Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2004
Publication Date: 1/20/2005
Citation: McCord, P.H., K.G. Haynes, B.R. Sosinski, M.E. Clough, and G.C. Yencho. 2005. Use of AFLP technology to develop molecular markers for internal heat necrosis (IHN). Amer. J. Potato Res. 87:80. (Abstract).

Interpretive Summary:

Technical Abstract: Potato is an important crop in the mid-Atlantic region. 'Atlantic', the most important chipping cultivar, is susceptible to internal heat necrosis (IHN), a physiological disorder resulting in necrotic patches in the parenchyma of the tuber. Improved cultivars are the best strategy for control of this disorder. A population of 4X clones has been developed using advanced S. tuberosum lines and 2n pollen of 2x S. phureja X S. stenotonum, that contains resistance to IHN. We are developing molecular markers for selection for IHN resistance, and to locate candidate genes for future investigation of the biochemistry of IHN. Markers are being developed using AFLP (amplified fragment length polymorphism) technology, combined with bulk segregant analysis (BSA). A total of 192 primer combinations were run on bulked DNA of 5 IHN-resistant and 5 IHN-susceptible plants (resistance based on multiple field trials). Putative polymorphisms were verified by rerunning reactions on the individuals of the bulks. Verified primer combinations were run a third time, using 32P-labeled primers, and polymorphic fragments were excised from the gel, cloned, and sequenced. Database searches using BLAST identified 3 R-gene clusters, 10 uncharacterized Solanaceae cDNAs, and 4 known genes. Unique clones (60 total) were converted into PCR-based markers and are currently being tested; fragments are being assayed on agarose and acrylamide gels, with and without restriction enzyme cutting. So far, one fragment with homology to a calcium-dependent protein kinase has been found that segregates for IHN resistance/susceptibility. This and other markers segregating in the BSA individuals will be tested on at least 10 additional plants to ascertain their utility for selection. (graduate student competition, breeding, PAA membership no. pending)

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