Mapping QTLs for sucrose content,yield and quality in a sugar beet population fingerprinted by EST-related markers

Seventy five expressed sequence tags (ESTs) that are associated with functions in carbohydrate and nitrogen metabolism were genotyped in 108 plants of an F2 population of sugar beet ( Beta vulgaris L.) segregating for sugar quality and yield parameters. Supplemented by known RFLP and AFLP markers, the resulting map spans 446 cM of the 758-Mbp genome of sugar beet. F3 test-cross plants were analysed for corrected sugar yield, beet yield, ion balance and the content of sugar, amino nitrogen, potassium and sodium in six locations. Twenty one significant quantitative trait loci (QTLs) were detected using the composite interval mapping approach. Expressed genes flanking the QTLs were identified in all cases. Correlations between QTLs and potential candidate genes are discussed.