Submitted to: Annual Beet Sugar Development Foundation Research Report
Publication Type: Research Notes
Publication Acceptance Date: 5/16/2006
Publication Date: 7/1/2006
Citation: Trebbi, D., McGrath, J.M. 2006. Genetic relationships between QTL for sucrose content and yield in a sugar x table beet (Beta vulgaris L.) wide cross. 2005 Annual Beet Sugar Development Foundation Research Report. p. D10-D27.
Technical Abstract: Sucrose yield is the primary trait for sugar beet, and simply considered, is a product of the total root harvest times the percent sucrose in harvested beets. Simultaneously increasing root weight and sucrose percent in fresh beets has been problematic because of an observed inverse relationship between yield and sucrose content; however reasons for this negative correlation have not been well defined physiologically. Physiological components (sucrose content as percent of both fresh and dry root weight, and water and dry matter percent) and yield components (root, sucrose, water and dry matter weights) were measured in field-grown selfed F3 progenies derived from a single sugar x table beet hybrid individual. This cross was chosen to maximize genetic diversity and facilitate analyses of sugar beet agronomic traits. All yield component measures were highly correlated with each other, and QTL analyses suggested each of these traits was oligogenic. Physiological component measures were not as well correlated with each other, and QTL analyses indicated that these also were oligogenic. Yield component QTLs often co-segregated with one another, and their relationship with physiological QTLs suggested at least two linkage groups harbor genes contributing to sucrose yield at both levels. Significantly, sucrose fresh weight QTLs co-segregated with either dry matter percent or sucrose percent of dry matter QTLs. Opposing alleles at oligogenic loci may explain, in part, the inverse correlation between root yield and sucrose content.