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United States Department of Agriculture

Agricultural Research Service

Simon: Release: B6253
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UNITED STATES DEPARTMENT OF AGRICULTURE
AGRICULTURAL RESEARCH SERVICE
WASHINGTON, D.C.  20250

with

THE CALIFORNIA AGRICULTURAL EXPERIMENT STATION
DAVIS, CALIFORNIA  95616

and

THE FLORIDA AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA  32611

and

THE WISCONSIN AGRICULTURAL EXPERIMENT STATION
MADISON, WISCONSIN  53706

RELEASE OF CARROT INBRED B6253 GERMPLASM

The Agricultural Research Service, United States Department of Agriculture, the
California Agricultural Experiment Station, the Florida Agricultural Experiment Station
and the Wisconsin Agricultural Experiment Station announce the release of a carrot
inbred B6253 to provide germplasm for developing improved genotypes and producing
hybrids.

B6253 was derived from a cross made in 1983 at the University of Wisconsin
between F524 (a dark orange Imperator-shaped inbred from Waltham Hicolor)
and B4367 (a dark orange Imperator-shaped inbred from an open-pollinated
synthetic consisting of fresh market varieties). Beginning at the F2 generation,
selection was made for dark orange color, long, smooth root shape, and small core
size. Two generations beyond the F2, selection was also initiated for mild, sweet
flavor. A select best plant self-pollinated in the 1985 breeding plots produced
seed for field row 6253 in Florida and California. Now at F2MSM3, B6253 is the
result of six generations of selection for root shape and color and four generations
for culinary quality. B6253 is a maintainer of sterility ("B" line) and a petaloid
cytosterile counterpart ("A" line) is in the Wisconsin Wild cytoplasm and now at
BC4. B6253 produces adequate pollen and seed.

Roots of B6253 are long (18-24 cm), tapered, very dark orange throughout, with a
small core. Root surface is generally smooth with minimal tendency for root forking
(sprangling). Tops of B6253 are of medium height and pale green with strong
attachment to the root. Carotene content of mature roots is 260 to 280 ppm
(compared to 70 to 100 ppm for older and 120 to 160 ppm for modern fresh market

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Carrot Inbred B6253, p. 2

varieties). Flavor is average. Minimal selection for disease resistance occurred during
the development of B6253 but intermediate to good tolerance to Alternaria leaf blight has
been observed.

Several hybrid combinations with B6253 have performed well in trials including
(B5280 x B6373) xB6253 in California and (B5344 x B2566) x B6253, (B5280 x B4367)
x B6253, and (B5280 x B6373) x B6253 in Florida. Hybrids of B6253 are of the United
States fresh market type and generally resist root forking.

Breeder's seed of B6253 will be prorated upon written requests before April 1, 1994,
addressed to P.W. Simon, USDA, ARS, Department of Horticulture, 1575 Linden Drive,
University of Wisconsin, Madison, WI 53706.

When this germplasm contributes to a new cultivar, it is requested that appropriate
recognition be given to its source.

______________________________       ___________________
Director, California Agricultural
Experiment Station

Date


______________________________
      ___________________
Director, Florda  Agricultural
Experiment Station

Date


______________________________
      ___________________
Director, Wisconsin  Agricultural
Experiment Station

Date


______________________________
      ___________________
Administrator,  Agricultural
Research Service

Date



Last Modified: 8/10/2004