A color chart to screen for high β-carotene in OFSP breeding
Orange fleshed sweetpotato (OFSP) varieties are considered as the first biofortified varieties among major food crops. About 100g fresh sweetpotato storage roots or less contain enough β-carotene to provide the daily provitamin A needs of a pre-schooler. However, determination of β-carotene by chemical methods is expensive. Since the storage root flesh color is highly correlated with the β–carotene concentrations in sweetpotato, color charts can be used to breed β–carotene rich sweetpotato varieties with nearly zero costs. The objectives of this study were to determine the β–carotene concentration of sweetpotato storage roots with a wide range of colors, to characterize the flesh color by color charts, and to associate each color with the corresponding β–carotene concentration. A total of 248 roots coming from 31 genotypes (2 roots per plot, 2 plot replications and 2 environments: La Molina and San Ramon) were classified by their flesh color using the Royal Horticulture Society color chart. Freeze dried samples of every roots were prepared and analyzed for total and β-carotene concentration by HPLC. Most of the roots showed a first and a secondary flesh color. Roots were grouped in 10 groups according to its primary flesh color. All roots with deep orange and orange primary flesh color showed significant β–carotene concentration (above 4 mg / 100 g fresh weight or 300 ug RAE). The β–carotene concentration of intermediate and pale orange primary flesh color ranged from 0.5 to 8 mg / 100 g fresh weight depending on the color intensity of the primary or secondary colors and their proportion. Roots with yellow orange, pale orange, yellow, intermediate yellow, pale yellow and cream primary flesh color had only very low amounts of β-carotene. The evaluated color chart might be a useful tool in breeding programs to select for high β–carotene cultivars.
Burgos, G.; Carpio, R.; Sanchez, C.; Sosa, P.; Porras, E.; Espinoza, J.; Grüneberg, W. A color chart to screen for high &#946;-carotene in OFSP breeding. Presented at 15th International Symposium of the International Society for Tropical Root Crops (ISTRC). Roots and tubers for sustainable development and food security: Issues and strategies. November 2-6, 2009. Lima, Peru. (2009) 47-52