Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 23, 2013
Publication Date: May 14, 2013
Repository URL: http://handle.nal.usda.gov/10113/56778
Citation: Fajardo, D., Haynes, K.G., Jansky, S.H. 2013. Starch characteristics of modern and heirloom potato cultivars. American Journal of Potato Research. 90(5):460-469. Interpretive Summary: The goals of potato breeders have changed since the introduction of processed products became important in the mid-twentieth century. This study was carried out to determine whether selection for processing quality traits influenced starch composition of potato tubers. Significant variation in amylose content of tuber starch and starch granule morphology was found among 20 modern and heirloom potato cultivars. However, the range of variation is likely not enough to affect cooking or nutritional quality.
Technical Abstract: In a number of ways, modern potato breeding efforts differ from those that created heirloom cultivars. Breeding efforts expanded from private breeders and government agencies to University programs. Concurrently, there was a deliberate effort by breeders to broaden the genetic base of parental clones through germplasm exchange. In addition, as a result of the rapid expansion of the potato processing industry in the mid twentieth century, potato breeders shifted their focus from fresh market varieties those intended for the fry and chip markets. Selection for higher dry matter content and lower reducing sugar levels in tubers were successful. Since potato tubers are primarily composed of starch, it is important to know whether other starch parameters also changed. This study sought to determine whether modern processing cultivars differ from heirloom cultivars for amylose:amylopectin ratio in tuber starch and for starch granule morphology. Since breeding efforts for processing potatoes have included the maintenance of tuber quality during storage, these parameters were measured in both fresh and stored tubers. Twenty cultivars selected to span the range of cultivar release dates in the U.S. were grown at Hancock, WI in 2009 and 2010 and evaluated for amylose:amylopectin ratio, starch granule surface area, starch granule length, and starch granule length:width ratio in freshly harvested and stored tubers.