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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #335529
Title: Reliability of measurement and genotype x environment interaction for potato specific gravity

Author
item WANG, YI - University Of Idaho
item SNODGRASS, LANCE - University Of Wisconsin
item Bethke, Paul
item BUSSAN, ALVIN - Wysocki Produce Farm Inc
item HOLM, DAVID - Colorado State University
item Novy, Richard - Rich
item PAVEK, MARK - Washington State University
item PORTER, GREGORY - University Of Maine
item ROSEN, CARL - University Of Minnesota
item SATHUVALLI, VIDYASAGAR - Oregon State University
item THOMPSON, ASUNTA - North Dakota State University
item THORNTON, MICHAEL - University Of Idaho
item ENDELMAN, JEFFREY - University Of Wisconsin

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2017
Publication Date: 3/13/2017
Publication URL: https://handle.nal.usda.gov/10113/5801875
Citation: Wang, Y., Snodgrass, L.B., Bethke, P.C., Bussan, A.J., Holm, D.G., Novy, R.G., Pavek, M.J., Porter, G.A., Rosen, C.J., Sathuvalli, V., Thompson, A.L., Thornton, M.T., Endelman, J.B. 2017. Reliability of measurement and genotype x environment interaction for potato specific gravity. Crop Science. 57(4):1966-1972. doi: 10.2135/cropsci2016.12.0976.

Interpretive Summary: The dry matter content of potatoes used to make potato chips and French fries strongly influences fry oil absorption and texture of the finished product and is therefore an important trait to the potato processing industry. Tuber specific gravity, a measure of tuber density relative to the density of water, is often used to assess the quality of chip and fry processing potatoes because it is strongly correlated with dry mater content and is easy to measure. For French fry processing varieties, the desirable range for mean specific gravity is 1.080–1.095 and little variability around the mean is essential for product uniformity. The reliability of potato specific gravity measurements was evaluated using potatoes from two multi-site, multi-year trials. Mean specific gravity measurements were highly repeatable, but the repeatability of the variation around the mean was low. Thus, large multi-environment trials are required in order to identify new varieties with the narrow specific gravity distribution desired by potato processors. These findings provide guidance to potato breeders and agronomists who conduct evaluations of potential new fry processing varieties on how best to identify varieties with superior tuber characteristics with respect to specific gravity. Comparisons between production environments showed a consistent regional pattern in mean specific gravity over time. There was a higher correlation in mean specific gravity between locations within the Pacific Northwest, Upper Midwest, and Northeast than between environments from different regions. Although breeding new varieties for nationwide production is an attractive idea, our results suggest that genetic improvements that deliver improvements in potato tuber quality to industry and consumers may be easier to achieve if new varieties are bred for production at the regional level.

Technical Abstract: The dry matter content of potatoes used to make potato chips and French fries strongly influences fry oil absorption and texture of the finished product. Specific gravity (SpGr) is often used to assess the processing quality of potatoes tubers because of its strong correlation with dry matter content and ease of measurement. . For French fry processing varieties, the desirable range for mean SpGr is 1.080–1.095 and a small variance around the mean is essential for product uniformity. The reliability of potato SpGr measurements was evaluated using potatoes from two multi-site, multi-year trials. Consistent with earlier studies, our data show that estimates of mean SpGr were highly repeatable: the median plot-basis value was 0.83 for a national trial with 6 locations and 3 years. In contrast, the median repeatability of the standard deviation between tubers was only 0.21. Thus, large multi-environment trials are required in order to identify varieties with a narrow SpGr distribution. Finlay-Wilkinson stability analysis of the mean, however, indicated that the SD of one potato variety was noticeably higher than the rest. When genotype BLUPs were regressed on the environment means, this variety had a regression coefficient of 2.1 compared to 0.4–1.4 for the other entries. The genetic correlation between environments showed a consistent regional pattern in mean specific gravity over time. There was a higher mean correlation between environments within the Pacific Northwest (0.97), Upper Midwest (0.91), and Northeast (0.85) than between environments from the different regions (0.35 to 0.78). Although breeding for national adaptation is an attractive idea, our results suggest that genetic gain may be easier to achieve at the regional level.