2017 ASHS Annual Conference
Identifying Late Blight Resistance QTL in a Diploid Mapping Population of Solanum microdontum
Identifying Late Blight Resistance QTL in a Diploid Mapping Population of Solanum microdontum
Thursday, September 21, 2017
Kona Ballroom (Hilton Waikoloa Village)
Phytophthora infestans (de Bary), the causal agent of late blight, is a devastating pathogen of potato (Solanum tuberosum). Our approach to crop improvement is to broaden the genetic base of potato through introduction of R genes for vertical resistance to P. infestans from wild potato germplasm sources. S. microdontum has previously been identified as containing a source of resistance to P. infestans, with a R-gene hotspot on chromosome 4. In this study, an F1 population of approximately 200 diploid individuals was generated by crossing MSBB953-10, as a parent with S. microdontum-based late blight resistance, with MSBB948-01, a susceptible diploid clone. The diploid population was screened for resistance by inoculating detached young greenhouse-grown leaves with a US23 isolate. Cultivar Katahdin and a transgenic three-R-gene Diamant line (RB, vnt1, and blb2) were used as susceptible and resistant checks, respectively. Inoculation results showed that the progeny ranged from highly susceptible to completely resistant within the progenies, on a 0-100% scale. Single nucleotide polymorphisms linked to late blight resistance quantitative trait locus (QTL) are observed by mapping the diploid population using the Infinium Potato 12k SNP array V2. QTL analysis for late blight resistance will be presented. Identifying novel R genes to introgress as scaffolds or use for “gene pyramiding” will be used for future cultivar development in the diploid potato breeding program at Michigan State University. The ultimate goal is to develop durable late blight resistance through stacking multiple R genes.