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United States Department of Agriculture

Agricultural Research Service

PHILIPP W. SIMON

Research Leader

Philipp Simon: Carrot and Garlic Genetics


Information

Carrot Trial Results

Information about USDA Carrot Lines

Original Variety Release Notices

Germplasm Resources

    Initiative for Future Agriculture and Food Systems (IFAFS) Project

    Specialty Crops Research Initiative

    Organic Agriculture Research and Extension Initiative - "Carrot Improvement for Organic Agriculture"

    Publications and Scientific Papers

    Articles On-Line

    Various Interesting Web Sites

    Carrot Pictures

    Carrot pigment variation

    They don't have to be orange, carrots can come in a wide variety of colors derived from several different pigments.
    Upper leftis a conventional "orange" carrot. The color is due mainly to beta-carotene, with some alpha-carotene, both of which are orange pigments.Center leftis a "yellow" carrot, whose color is due mainly to xanthophylls (a type of carotene). Bottom leftis a "red" carrot, due mainly to lycopene (another type of carotene, also found in tomatoes), in addition to some beta- and alpha-carotene. Upper rightis a "purple" carrot, due to pigments in an entirely different class, the anthocyanins. Lower rightis a "white" carrot, the color of a carrot with none of these pigments.
    Click here for a larger version (380x560) 164kb
    Click here for a high resolution version (2460x3348) 559kb

    Root color genes Root color genes-- P 1, Y, L.

    Darker Purple- Variation in anthocyanin pigments occurs naturally in carrots. Classical breeding methods are being used to cross some of these types, and select the darkest purple carrots with higher levels of pigments.
    A-Plus carrot 'A Plus'New darker-orange varieties of carrots have been produced by the breeding program. This picture shows one USDA Carrot Variety, 'A Plus', which is high in carotene levels.

    High carotene carrots High carotene carrots
    Left: Beta III, 280 ppm carotene
    Center: Progenitor, 140 ppm carotene
    Right: HCM (High Carotene Mass), 500 ppm carotene

    beta-carotene


    Carrot breeding - seed production
    Carrot breeding- Small (left) and large (right) isolation cages which are used for controlled crossing of one or more carrot plants. 

    Breeding Plot Cage Carrot breeding

    Left: one small isolation cage used for controlled pollination of carrots. (click on photo for larger version)

    Right: Inside the carrot isolation cages. Bees are pollinating the carrot flowers.


    Carrot Root Sugar Gene Rs Root sugar gene Rs- This single gene in carrot controls the type of sugar in the root.

    Sucroseis a disaccharide, composed of one molecule of fructoseattached to one molecule of glucose. Fructose and glucose are reducing sugars, and sucrose is a non-reducing sugar. Thus, the gene name Rsstands for reducing sugar.

    When this dominant allele (Rs) is present, the carrot root will accumulate the reducing sugars fructoseand glucose. When both recessive alleles (rsrs) are present, the carrot root will accumulate primarily sucrose.

    These graphs show the distribution of sugar types when a low reducing sugar type rsrs(P1) was crossed with a high reducing sugar type RsRs(P2), producing a hybrid offspring Rsrs(F1). Because Rs is dominant, the F1 resembles P1.

    A backcross of the F1 with P2 (designated BC1P2) is half RsRsand half Rsrs, both of which are high reducing sugar types.

    The F1 selfed (F2) should show a 3:1 segregation, due to the distribution of the three possible genotypes 1:RsRs, 2:Rsrs, 1:rsrs.


    Garlic Pictures

    Garlic seedling Garlic true seed production- this plant was produced from a true seed of garlic, a rare event, since cultivated garlic has been exclusively propagated vegetatively for many hundreds of years.

    Garlic coat of arms, 1450-1500, Germany Garlic coat of arms, 1450-1500, Germany

    Garlic, Allium sativum, from the book Hortus Sanitatis, Mainz, 1485. Garlic, Allium sativum, from the book Hortus Sanitatis, Mainz, 1485.


    Last Modified: 5/27/2014
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