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  • Author or Editor: George L. Hosfield x
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Seed coat color in dry bean (Phaseolus vulgaris L.) is determined by the presence or absence of tannins, flavonoids, and anthocyanins. Black beans contain three main anthocyanins that are responsible for their black seed coat color: delphinidin 3-O-glucoside, petunidin 3-O-glucoside, and malvidin 3-O-glucoside. Leaching of anthocyanins occurs in many black bean genotypes during thermal processing (i.e., blanching and cooking). Black beans that lose their dark color after processing are unacceptable to the industry. Since the marketability of black beans can be adversely affected by thermal processing, an experiment was conducted to ascertain whether pigment leaching was due to qualitative or quantitative changes in anthocyanins during processing. Four black bean genotypes that showed differential leaching of color were investigated. `Harblack' retains most of its black color after processing while `Raven' loses most of its color. `Black Magic' and `Black Jack' are intermediate between `Harblack' and `Raven' in processed color. Bean samples (119 ± 1.5 g) of the four genotypes were thermally processed in 100 x 75-mm tin cans in a pilot laboratory. Seed coats were removed from the cooked beans, freeze-dried, and placed in solutions of formic 10 acid: 65 water: 25 methanol to extract anthocyanins. The extracts were analyzed by HPLC. Although all genotypes retained some color, there were no detectable anthocyanins in seed coats of the cooked beans. In a second experiment, raw beans of each genotype were boiled in distilled water for 15 minutes. All four genotypes lost color during boiling, but `Harblack' retained most of its color and had a five-fold higher concentration of the three anthocyanins than did the other genotypes. `Harblack' may retain color better than other black beans because of physical characteristics of the seed coat.

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The mutant trait glabrous seedstalk was observed in carrot (Daucus carota L.) inbred W93 and, in crosses with pubescent inbred MSU 1558, was found to be controlled by a single recessive gene, gls. Cytoplasmic effects on the expression of the character were not detected. Glabrous seedstalk has practical application as a genetic marker to detect outcrosses in hybrid carrot seed production fields.

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Dry bean (Phaseolus vulgaris L.) seed coat color is determined by the presence and relative amounts of phenolics, flavonoids, and anthocyanins present in the lumen of epidermal cells. Some of these chemicals may interact with proteins of the cotyledon to form complexes that render beans hard to cook and digest. Eight genetic loci control seed pigment chemistry. When all eight loci are dominant, a shiny black seed coat results, but recessive substitutions at one or more loci yield colors ranging from white, yellow, and brown to dark violet. In order to relate Mendelian genes for seed coat color to the pigments formed, we studied eight genetic stocks that had recessive substitutions at one or more color-determining loci in an otherwise all-dominant genetic background. Seed coat from each genotype was extracted exhaustively with hexane, EtOAc, MeOH, MeOH:H2O 1:1, and H2O 100%. Silica gel thin-layer chromatography (TLC) (solvent system CHCl3:MeOH 4:1) analysis of the MeOH fraction showed that one genotype had no phenolic compounds and two had only simple phenols. Once flavonol glycoside was present in relatively large amounts in four of the genotypes, but absent in genotypes with anthocyanins. Cellulose TLC (2-dimensional, Butanol:Acetic Acid:H2O 4:1:5 first dimension, 1% HCl second dimension) of the anthocyanin-containing genotypes showed that the presence of one flavonol and three anthocyanidin-3-glycosides (UV spot color and color shift with NH3). The relative importance of the seed coat chemicals in digestibility and their antioxidant will also be discussed.

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Ninety-eight percent of the navy beans (Phaseolus vulgaris) grown in the US are processed. Thus, new cultivars considered for release must meet industry standards. Canning quality behaves as a classical QTL which precludes its selection and evaluation in early generations. Such delays add a measure of inefficiency to a breeding program. Indirect selection for canning quality using molecular markers could increase efficiency. RAPD markers are more useful than RFLP's, in Phaseolus, due to a simpler protocol and a higher level of polymorphism within genetically related cultivars. Three populations of RIL's, derived from crosses between cultivars with standard and sub-standard canning quality, were screened to identify markers associated with canning quality. Material for evaluation was grown at two locations, in three replications and processed, in the Food Science Processing Lab, following industry standards. Quality traits measured were: processed texture, color and appearance. Associations of putative markers with canning quality were identified using ANOVA and Mapmaker programs

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