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Keith O. Fuglie

nutrition (especially higher levels of β-carotene, a precursor to vitamin A), insect resistance, and higher dry matter yield (primarily for starch and flour processing). Regionally, the rankings for sweetpotato crop improvement constraints tended to score

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Huihui Zhang, Ping Yu, Min Song, Dalu Li, Qianqian Sheng, Fuliang Cao, and Zunling Zhu

rapidly decreased in October, and the decrease from October to November was the lowest in this cultivar. Fig. 2. Dynamic changes in the Chl a content ( A ), Chl b content ( B ), Chl content ( C ), carotene content ( D ), Chl a /Chl b content

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Dean A. Kopsell and Carl E. Sams

regions (430 and 453 nm, respectively) of the visible light spectrum. In contrast, absorption of the carotenoid pigments of lutein (LUT) and β-carotene (BC) are highest in the blue region at 448 and 454 nm, respectively ( Lefsrud et al., 2008

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T. Casey Barickman, Dean A. Kopsell, and Carl E. Sams

et al., 2013 ). The de novo synthesis of carotenoids in the tomato fruit tissue, mainly lycopene and β-carotene, are associated with the color changes from green to red as chloroplasts are transformed to chromoplasts ( Pék et al., 2010 ). Thus, the

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Cecilia E. McGregor and Don R. LaBonte

`White Jewel' is a yellow-and-orange fleshed spontaneous mutant of the orange-flesh sweetpotato [Ipomoea batatas (L.) Lam.] cultivar Jewel. Mutations in storage root flesh color, and other traits are common in sweetpotato. The orange flesh color of sweetpotato is due to β-carotene stored in chromoplasts of root cells. β-carotene is important because of its role in human health. In an effort to elucidate biosynthesis and storage of β-carotene in sweetpotato roots, microarray analysis was used to investigate genes differentially expressed between `White Jewel' and `Jewel' storage roots. β-carotene content calculated from a* color values of `Jewel' and `White Jewel' were 20.66 mg/100 g fresh weight (FW) and 1.68 mg/100 g FW, respectively. Isopentenyl diphosphate isomerase (IPI) was down-regulated in `White Jewel', but farnesyl-diphosphate synthase (FPPS), geranylgeranyl diphosphate synthase (GGPS), and lycopene β-cyclase (LCY-b) were not differentially expressed. Several genes associated with chloroplasts were differentially expressed, indicating probable differences in chromoplast development of `White Jewel' and `Jewel'. Sucrose Synthase was down-regulated in `White Jewel' and fructose and glucose levels in `White Jewel' were lower than in `Jewel' while sucrose levels were higher in `White Jewel'. No differences were observed between dry weight or alcohol insoluble solids of the two cultivars. This study represents the first effort to elucidate β-carotene synthesis and storage in sweetpotato through large-scale gene expression analysis.

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Vuvu D. Manseka and James R. Hicks

Butternut squash was harvested at two stages of maturity in 1994 and was cured for 10 days at 26°C and 80% or 95% relative humidity (RH) before storage in air at 12°C and 65% or 80% RH for 144 days. Fresh weight was assessed right after harvest along with carotene (milligram per 100 grams fresh weight), carbohydrates (milligrams per gram dry weight) and internal color (L, a, b). Percent weight loss and all quality components were assessed immediately after curing and every 48 days thereafter. Weight loss increased with days in storage and was substantially minimized by a humidified environment down to 6%. The 95% curing treatment reduced weight loss to levels below the upper threshold for consumer acceptance (<15%) after 144 days. Maturity at harvest did not affect weight loss during storage, but rather the percent dry weight. Beta-carotene increased by >100% during storage. A positive correlation was established between weight loss and beta-carotene and also between the a value and beta-carotene. Curing at 95% RH obviously reduced beta-carotene content to less than one-third of its corresponding amount in noncured fruit. Sucrose increased as glucose and fructose and starch decreased during storage in cured and noncured fruit. Starch was found to decrease by 26% after 144 days in storage. The lowest levels of starch were found early during storage in fruit cured at 95% RH, but the difference between treatments disappeared by the end of storage.

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Allan F. Brown, Gad G. Yousef, Ivette Guzman, Kranthi K. Chebrolu, Dennis J. Werner, Mike Parker, Ksenija Gasic, and Penelope Perkins-Veazie

neochlorogenic acid), flavan 3-ols (catechin, epicatechin, procyanidins), flavonols (quercetin 3-glucoside and 3-rutinoside), and ANC (cyanidin 3-glucoside and 3-rutinoside) ( Tomás-Barberán et al., 2001 ). The carotenoid profile of peach includes β - carotene, β

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Dean A. Kopsell, Kimberly J. Whitlock, Carl E. Sams, and David E. Kopsell

and tissue concentrations of lutein and zeaxanthin and macular pigment density Amer. J. Clin. Nutr. 71 1555 1562 Kopsell, D.A. Kopsell, D.E. Lefsrud, M.G. Curran-Celentano, J. Dukach, L.E. 2004 Variation in lutein, β-carotene, and chlorophyll

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Brian J. Just* and Philipp W. Simon

While the carotenoid biosynthetic pathway has been studied several horticultural and agronomic crops, very little information exists for this conserved pathway in carrot, a primary source of dietary carotenoids. Though orange carrots are the most familiar color to Western consumers, yellow, red, and white carrots also exist and have been historically important. Modern carrot breeders are showing renewed interest in these unusual color phenotypes. Beta- and alpha-carotene are the primary pigments in orange carrot roots. Yellow carrots accumulate xanthophylls (oxygenated carotenes), red carrots accumulate lycopene (the precursor to alpha- and beta-carotene), and white carrots accumulate no detectable pigments. Differences between these phenotypes are usually monogenic or oligogenic. Our research has focused on identifying putative genes for carotenoid biosynthetic enzymes in the carrot genome, mapping them, and examining expression patterns in various tissues and carrot root pigment phenotypes. We are using this information to create a carrot pigment biosynthesis function map incorporating biosynthetic enzymes, major carrot color genes, and gene expression information.

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Kil Sun Yoo*, Julio Loaiza, Kevin Crosby, Leonard Pike, and Steve King

About 40 watermelon samples with various flesh colors (red, pink, orange, and yellow) were tested for their carotene, sugar, and ascorbic acid contents. Carotenoids were separated and purified by using a preparative HPLC system and identified by comparing the spectra with standard compounds by using a diode array detector. Sugar and ascorbic acid contents were measured by HPLC methods. Red and pink colored watermelon contained lycopene as the major carotenoid, with a wide range of variation (5 to 51 μg·g-1). Beta-carotene was the second major carotenoid and was less than 6 μg·g-1. There were also lutein and violazanthin in less than 1.5 μg·g-1 range. Yellow and orange flesh watermelons contained a complex mixture of carotenes. Prolycopene, lycopene, or beta-carotene was the major component, depending on the variety, and the contents were less than 24, 3, and 9 μg·g-1, respectively. There were also minor carotenoids, such as violaxanthin, lutein, neurosporene, zea-carotene with a 0 to 3.5 μg·g-1 range. Neurosporene, zea-carotene, and prolycopene were not found in the red watermelons. There was great variation in total sugar content, range being from 22 to 102 mg-1, while the °Brix was from 4.0 to 15.5. Sucrose, glucose, and fructose were the main sugars in the watermelon and their composition were grouped as sucrose-dominant or fructose-dominant groups. Some varieties with very low levels of sucrose were generally low in the total sugar content. Watermelon contained fairly low levels of ascorbic acid, less than 58 μg·g-1 and some varieties had nearly no ascorbic acid. Estimation of total carotenoid in the yellow watermelons by measuring absorbency at 435, 485, or 503 nm was tested and 435 nm showed the highest correlation coefficient (r 2 =0.845).