Carotenoid content and color in diploid potatoes

The yellow pigment in potato (Solanum L. sp.) tuber flesh is caused by vari ous carotenoids that may protect against cancer, cardiovascular disease, an d macular eye degeneration. The objectives of this research were to 1) iden tify and quantify the carotenoids present in I I diploid clones from a hybr id population of Solanum phureja ssp. phureja Juz. & Bukasov-S. stenotomum ssp. stenotomum Juz. & Bukasov and two tetraploid potato cultivars (the yel low-fleshed 'Yukon Gold' and the white-fleshed 'Superior'), and 2) determin e the relationship between tuber yellow intensity and carotenoid content. Y ellow intensity was measured by a colorimeter programmed to calculate a yel lowness index, YI E-313. Carotenoid analyses were performed on an automated high-performance liquid chromatography system with software for integratio n and quantitation with detection at 450 urn using a diode array detector. Six major carotenoids were detected: neoxanthin, violaxanthin, lutein-5,6-e poxide, lutein, zeaxanthin, and an unknown carotenoid. Total carotenoid con tent in the yellow-fleshed diploid clones was 3 to 13 times higher than 'Yu kon Gold' and 4 to 22 times higher than 'Superior'. Both total and individu al carotenoid contents were positively correlated with tuber yellow intensi ty. There was an exponential relationship between total carotenoid content and tuber yellow intensity. This suggests that selecting for more intense y ellow flesh will result in higher levels of carotenoids. These specific dip loid clones were selected for this study because they produced at least fiv e percent 2n pollen; they have the potential to make significant contributi ons to improving the nutritional status of tetraploid potatoes through 4x-2 x hybridizations.