POTATO

Shelley JanskyUSDA-ARS and UW-Madison

What is the optimal ploidy of potato?

Stupar et al. 2007. Phenotypic and transcriptomic changes associated with potato autopolyploidization. Genetics 176:2055-2067.

Does phenotypic diversity mirror genetic diversity?

Jansky et al. 2015. How do we address the disconnect between geneticand morphological diversity in germplasm collections? Am. J. Bot. 102:1-3.

Have breeding efforts increased genetic diversity?

Hirsch et al. 2013. Retrospective view of North American potato breeding in the 20th

and 21st centuries. G3 3:1003-1013

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Managing genetic diversity is more important than increasing it

Regarding vegetatatively propagated plants “…the extensive segregation and recombination that occur during sexual reproduction lead to very large numbers of novel genotypes, nearly all of which are inferior to the parental genotype. Thus, improvement tends to be slow”

Allard, R. 1999. History of plant population genetics. Ann. Rev. Genet. 33:1-27.

Regarding vegetatatively propagated plants “…the extensive segregation and recombination that occur during sexual reproduction lead to very large numbers of novel genotypes, nearly all of which are inferior to the parental genotype. Thus, improvement tends to be slow”

“…inbreeding (especially selfing) is capable of binding the entire genotype together, including favorably interacting alleles of different loci located on different chromosomes. “

Allard, R. 1999. History of plant population genetics. Ann. Rev. Genet. 33:1-27.

Inbred lines allow us to:

1. Remove deleterious alleles

2. Fix valuable alleles

3. Assemble desirable epistatic interactions

“Tetraploidy, together with severe inbreeding depression upon repeated selfing, renders the

generation of pure lines, recombinant inbred lines, or near-

isogenic lines impractical.”

Gebhardt, C. 2013. Bridging the gap between genome analysis and precision breeding in potato. Trends in Genetics 29: 248-256

DM 1-3 x M6

F1

F2 population

self

Are the populations reaching homozygosity?

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F2 F3 F4

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actual