| UNITED STATES DEPARTMENT OF AGRICULTURE|
AGRICULTURAL RESEARCH SERVICE
CALIFORNIA AGRICULTURAL EXPERIMENT STATION
RELEASE OF CARROT BREEDING LINE B3475
The United States Department of Agriculture, Agricultural Research Service, and
the California Agricultural Experiment Station announce the release of carrot
inbred B3475, a petaloid, cyto-sterile parent for use in the production of
fresh market hybrids and as a genetic stock for use in the development of new
parent lines. It is the male-sterile component of a three-way hybrid, (B3475X
x B4367M) x F524, intended for release as soon as pilot production and
commercial trials can be completed. The other lines involved (B4367M and F524)
have been released for use in the hybrid Orlando Gold. Release of B3475 is
made now to permit seedsmen to test it in experimental hybrid combinations with
their own lines and to produce the proposed Fl seed parent B3475 x B4367M.
B3475 originated from a cross made at the University of Wisconsin in 1969
between two maintainer inbreds B10138 derived from the open pollinated cultivar
Danvers 126 and MSU 5931 derived from Imperator 58. MSU 5931 was released in
1968 for use with MSU 6000 in producing hybrid Spartan Sweet. Roots selected
for color and market type in F2 were massed under screen and from the
resulting population, ten were self pollinated and crossed to a cyto-sterile
tester. In the Fl and subsequent backcrosses, B3475 proved to be a reliable
maintainer. After S3 and BC2 the line has been propagated under large
screen isolators using ten or more roots. Eight backcrosses to the
cyto-sterile line and rigid selection on the maintainer side have resulted in
excellent uniformity and the sterile line, B3475S, appears to be identical with
its maintainer, B3475M, in all phenotypic details.
B3475 is a market type carrot 6-7 inches in length, with rounded shoulders,
tapered to the tap root with little tendency to become blunt at maturity.
Color is uniform, with indistinct zoning and no tendency to develop green in
the shoulders or the upper core. In the reproductive cycle, it exhibits a
distinct green corolla with small petals. Flowering is late, resulting in some
problems with achieving simultaneous flowering in crosses with unrelated lines.
One outstanding characteristic is excellent combining ability for seed yields.
In experimental production its Fl with B4367 has produced exceptionally high
yields in combination with a wide range of pollinators.
Breeders' seed of both the maintainer line (B3475M) and its pollen sterile
companion line (B3475S) will be distributed on a pro-rata basis to seedsmen who
make a written request to C. E. Peterson, USDA, ARS, Department of
Horticulture, University of Wisconsin, Madison, WI 53706, before
April 1, 1983.
Director, California Agricultural Experiment Station Date:
Administrator, Agricultural Research Service Date: