Simon: Release: B3475

UNITED STATES DEPARTMENT OF AGRICULTURE                         AGRICULTURAL RESEARCH SERVICE                                      and                  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.

-2- 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:

---