|Vega, S - UNIV OF WISCONSIN|
|Del Rio, A - UNIV OF WISCONSIN|
|Jung, G - UNIV OF WISCONSIN|
|Palta, J - UNIV OF WISCONSIN|
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2003
Publication Date: November 15, 2003
Citation: Vega, S.E., Del Rio, A.H., Jung, G., Bamberg, J.B., Palta, J.P. 2003. Marker-assisted genetic analysis of nonacclimated freezing tolerance and cold acclimation capacity in a backcross solanum population. American Journal of Potato Research. 80:359-369. Interpretive Summary: Potato is the world's most important vegetable crop, and one of our best hopes for feeding an increasingly hungry world. One limitation to expanded potato production is a lack of frost hardiness in all current commercial varieties. However, some wild relatives of potato can withstand very hard frosts. They are able to survive sudden frosts, and, in some cases, are also able to increase their tolerance of cold if "acclimated" by exposure to cool temperatures for a few days. Hybrid families were produced that contained both cold hardy and sensitive plants. These plants were characterized individually for cold hardiness traits, and also for the presence of DNA markers. By doing this, it was possible to link the markers with cold hardiness, and thereby identify areas on the potato chromosomes that likely contain genes for cold hardiness. This information will be useful for determining exactly which genes promote cold hardiness, how they do it, and the most efficient strategies for breeding this valuable trait into future varieties.
Technical Abstract: Random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were used to construct a partial genetic linkage map in a potato backcross population. The population, derived from two diploid wild Solanum species (frost tolerant, able to cold acclimate S. commersonii; frost sensitive, unable to cold acclimate S. cardiophyllum) was used to map quantitative trait loci (QTL) of nonacclimated relative freezing tolerance (NARFT) and cold acclimation capacity (CAC). Precise assessment of these traits allowed distinction of small but significant differences among 35 backcross genotypes. NARFT and CAC were poorly related in the segregating population, suggesting independent genetic control. The linkage map spanned 479.4 cM and included 77 RAPD markers and two SSR markers with 38 RAPD and 10 SSR unassigned markers. Two QTLs for NARFT were detected in two different linkage groups accounting for 44.0 % of the phenotypic variation for this trait. Two QTLs for CAC were detected accounting for 24.9 % of the phenotypic variation for this trait. QTLs for NARFT and CAC were detected at separate genomic regions, consistent with previous studies reporting cold hardiness as a polygenic trait. QTLs for NARFT and CAC were detected in a linkage group identified as part of chromosome V, suggesting that such chromosome constitutes a prime candidate for fine-mapping in the future. Due to the relatively small progeny size evaluated in this study, additional QTLs for NARFT and CAC could have been involved but not identified. Therefore, the conclusions derived from this study should be considered preliminary.