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 B7254 GERMPLASM

The Agricultural Research Service, United States Department of Agriculture, the
California Agricultural Experiment Station, Florida Agricultural Experiment Station and
Wisconsin Agricultural Experiment Station announce the release of a carrot inbred
B7254 to provide germplasm for developing improved genotypes and producing hybrids.

B7254 was derived from a cross made in 1983 at the University of Wisconsin between an
inbred derivative of B4367 (a dark orange Imperator-shaped inbred from an open-
pollinated synthetic consisting of fresh market varieties) and PI419042 (a Nantes-
Danvers-shaped Chinese variety, Hong Ting Hsain, which varies widely for root color)
crossed with B6345 (a dark orange inbred derived from Danvers and Chantenay
germplasm). Beginning at the F₂ generation, root selection was made for dark orange
color, medium length, blunt tips, smoothness, narrow shoulders, and for single tops. One
generation beyond the F₂, selection was also initiated for mild, sweet flavor. The best of
five plants self-pollinated in the 1986 breeding plots produced seed for field row 7254 in
Florida and California. Now at F₂MS₂M₃, B7254 is the result of seven generations of
selection for root shape and color and five generations for culinary quality. B7254 is a
maintainer of sterility ("B" line) and a petaloid cytosterile counterpart ("A" line) in
Wisconsin Wild cytoplasm is now at the BC₃ generation. The A line has white petal
color and a slight tendency for low levels of male fertility. B7254 is a moderate to poor
seed producer.

Roots of B7254 are short to medium long (14-19 cm), tapered, uniformly blunt, with a
small core. Root color is prone to yellow cambium ("zone") and pale phloem stippling

Carrot Inbred B7254, p. 2

("spongy") in some growing conditions. Root surface is smooth. Tops of B7254 are of
average size and height with multiple tops in the inbred but not its hybrid combinations.
Carotene content of mature roots is 150 to 170 ppm (compared to 70 to 100 ppm for
older and 120 to 160 ppm for modern fresh market varieties). Flavor is mild and fairly
sweet. B7254 has average tolerance to Alternaria leaf blight.

Several hybrid combinations with B7254 have performed well in trials including
(B2302 x B6366) x B7254 in both Florida and California.

Breeder's seed of B7254 will be pro-rated 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.