Project Number: 6645-41000-007-10
Project Type: Reimbursable

Start Date: Jul 01, 2011
End Date: Jun 30, 2014

Objective:
1. Rapid development and introduction of improved purple-fleshed sweetpotato (PFSP) varieties with higher pigment yield, better adaptation and disease resistance. 2. Develop near infrared spectroscopic (NIRS) method for high throughput screening and breeding of PFSP lines for increased anthocyanin content and varied cyanidin-peonidin ratios with specific color characteristics.

Approach:
Advanced PFSP breeding lines from NCSU Sweetpotato Breeding Program will be evaluated for anthocyanin profiles and color characteristics. Anthocyanins will be extracted from freeze-dried samples using a Dionex ASE 200 accelerated solvent extractor. Total monomeric anthocyanin (TMA) content will be determined by pH-differential method. The extract will be acid hydrolyzed in a screw-cap vial at 100ºC for 1 hr for anthocyanin analysis. Anthocyanin and anthocyanidin compounds will be separated and identified by high pressure liquid chromatography (HPLC). Relationship between cyanidin-peonidin ratios and color values (L*, a*, b*) of the extracts will be assessed. Near-infrared (NIR) spectroscopy will be used to develop a more efficient and cost effective method for rapidly analyzing anthocyanin components. Samples will be scanned in the diffuse reflectance mode (400-2500nm) of NIR spectrometer. The mean NIR spectra of the analyzed samples will be modeled against the data generated by pH-differential and HPLC methods using partial least square regression, and the regression models will be validated by full cross-validation. Standard curves that relate the NIR spectra and quantitative measurements of anthocyanin components will be used for speeding up the breeding efforts in developing specific PFSP varieties that have exceptional agronomic and high anthocyanin traits for natural colorant markets.