GENOMICS APPROACHES FOR IMPROVING NUTRITIONAL QUALITY OF FOOD CROP SPECIES
Location: Plant, Soil and Nutrition Research
Title: Quantitative trait loci analysis of endosperm color and carotenoid content in sorghum grain
| Salas Fernandez, Maria - CORNELL UNIVERSITY |
| Hamblin, Martha - CORNELL UNIVERSITY |
| Rooney, William - TEXAS A&M UNIVERSITY |
| Tuinstra, Mitchell - KANSAS STATE UNIVERSITY |
| Kresovich, Stephen - CORNELL UNIVERSITY |
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 13, 2008
Publication Date: February 10, 2008
Citation: Salas Fernandez, M.G., Hamblin, M., Li, L., Rooney, W.L., Tuinstra, M.R., Kresovich, S. 2008. Quantitative trait loci analysis of endosperm color and carotenoid content in sorghum grain. Crop Science. 48:1732-1743.
Interpretive Summary: Vitamin A deficiency is a global problem which affects approximately 250 million children in the world. Sorghum is a major staple crop in the area where vitamin A deficiency is prevalence. Breeding high provitamin A sorghums has a great impact on food security and health of poor people in the world. This work studied the genetic basis of variation in carotenoid levels in sorghum endosperm and detected several quantitative trait loci associated with sorghum carotenoid content and endosperm color for breeding high provitamin A sorghums.
Vitamin A deficiency affects approximately 250 million people in semiarid regions of Africa and Asia, where sorghum is a major staple crop. Yellow endosperm sorghums contain carotenoids, some of which can be transformed by humans into vitamin A. Our objective was to study the genetic basis of variation in carotenoid levels in sorghum endosperm by mapping quantitative trait loci associated with carotenoid content and endosperm color, as a putative predictor of carotenoid concentration. A recombinant inbred line population developed from a yellow endosperm (KS115) by a white endosperm (Macia) parental cross was evaluated in two locations in 2005. A genetic map was generated using 112 molecular markers including nine carotenoid candidate genes. Lutein, zeaxanthin and beta-carotene were the major carotenoids identified. Several QTLs were detected for each compound as well as for color and total carotenoids. Color was significantly correlated with the levels of all compounds, and color QTLs co-localized with carotenoid QTLs. For ß-carotene (provitamin A), five QTLs were localized on chromosomes 1, 2 and 10. One of them, on chromosome 2, was stable across both environments, had positive additive effects (1.179 and 1.379), explained large proportions of the phenotypic variance (11.6% and 15.15%) and was associated with a phytoene synthase gene (Psy3). This first report of QTLs for carotenoid content in sorghum grain provides a starting point for breeding high provitamin A sorghums.