DNA microarray-based discovery of molecular markers for the improvement of tomato color and nutritional quality

Quantification of lycopene and β-carotene in tomato varieties Five processing tomato varieties were evaluated for their carotenoid content (Table 1). The proximal end of each fruit was cut and fruits were categorized as either non-affected by YSD or affected by YSD. Carotenoid extraction was carried out under red light following a hexane/acetone-based protocol (Ferruzzi et al., 1998). Separations were achieved using a Waters 2690 reverse-phase HPLC system equipped with a photodiode array detector and a C18 column (Vydac 201TP54; 4.6mm x 250 mm). The peak identification and the subsequent quantification of β-carotene and lycopene were achieved using the standard curve for each compound and their molar absorptivity coefficients (Nguyen et al., 2001). Phenotypic evaluation of ABC2_BC2 A BC2 breeding population, S. lycopersicum (OH88119) x S. pimpinellifolium (PI128216), was evaluated for color in replicated trials. At harvest, the cut surface of the proximal end of 12 fruits from each plot were scanned at 200dpi. The images were analyzed with the color function of the Tomato Analyzer software (Brewer Talbot et al, in press) and objective measurements for color were collected (Figure 1). The color parameters of the Tomato Analyzer are based on the RGB color system. Algorithms were developed to convert the RGB values to L, a, b values, which were then used to calculate chroma, √(a2+b2), and hue, 180/π*acos(a/√(a2+b2)). The L coordinate represents lightness to darkness. Chroma is defined as saturation or intensity of color and hue represents the colors of the color wheel. The extent of YSD was obtained from the number of pixels that fall outside of the range hue=15, which is considered non-red tissue. To encompass both color and color uniformity, an index was computed from L, hue and YSD values. DNA microarray-based discovery of molecular markers for the improvement of tomato color and nutritional quality Audrey Darrigues1, Wencai Yang2, David M. Francis1 1Dept. of Horticulture and Crop Science, The Ohio State University, OARDC, 1680 Madison Avenue, Wooster OHIO 44691 2Dept. of Vegetable Science, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China