Simon: Release: B9253

UNITED STATES DEPARTMENT OF AGRICULTURE                         AGRICULTURAL RESEARCH SERVICE                                      and                           THE CALIFORNIA AND FLORIDA                        AGRICULTURAL EXPERIMENT STATIONS                         RELEASE OF CARROT INBRED B9253 The United States Department of Agriculture, Agricultural Research Service in cooperation with the California and Florida Agricultural Experiment Stations announce the release of a market-type carrot inbred, B9253, for direct use as a pollen parent in hybrid cultivars and as a source genotype for use in breeding for improved market quality.  A hybrid (B3475 x B4367) x B9253, will be released as soon as pilot seed production and commercial trials can be accomplished.  This line is released now to permit seedsmen to build up a supply of stock seed and to begin testing B9253 in experimental hybrids. B9253 was derived from a cross made in 1976 at the University of Wisconsin between plants selected from inbred lines, B4367M and B3187C.  B4367M originated from a breeding population derived by massing eight Fl hybrids involving sixteen selected inbreds.  After four cycles of mass selection, one of several related S3 lines became B4367M, later released for use in hybrids, Orlando Gold, Golden State and Candy Pack.  The other parent, B3187C, originated from a cross between two lines from Michigan State University (MSU 5986 x MSU 106) inbred to S3, then maintained by 5 cycles of mass selection.  B3187C restores pollen fertility in crosses with petaloid cytosteriles.  The inbred B9253 has not been tested for the presence of maintainer genes and no effort has been made to establish a companion male-sterile line. At the University of California, Imperial Valley Field Station (IVFS), El Centro, in March 1979, ten F3 roots from the cross B4367 x B3187, selected from field row 9253, were returned to Madison, Wisconsin and isolated under screen to complete the first of five cycles of mass selection.  During these mass increases seventeen different Fl females parents were used to produce experimental hybrids for trials in California and Florida.  At the University of California (IVFS) in 1984 the 3-way hybrid (B3475 x B4367) x B9253, received the highest average appearance score from 49 judges who rated 130 experimental hybrids and standard cultivars.  At the same location in 1983 with 25 judges and 114 entries three of the top six were hybrids with B9253 as the pollen parent.  In Florida the B9253 crosses have received only average scores.

(2) Roots of B9253 are smooth, 7-9 inches long, nearly cylindrical with semi-blunt tip.  Exterior and interior color is excellent with little contrast between xylem and phloem and slight tendency to develop a light cambium zone. Carotene content in B9253 is high, averaging 180 ppm (fresh wt) compared with 85 ppm in Imperator 58, the most widely grown variety in California. Because flavor is somewhat harsh, care must be taken to select mild flavored female parents to avoid producing hybrids with undesirable flavor.  In the seed cycle the line is vigorous, produces abundant pollen and good seed yields on a wide range of female parents.  At Sanford, Florida in field-exposure tests for resistance to Alternaria leaf blight, B9253 received a rating of 3.5 on a scale of 1 = resistant to 5 = susceptible.  In areas where Alternaria blight is severe B9253 and its hybrids should be grown only for trial to determine if Alternaria will be a serious problem. Breeders seed of B9253 grown in screen cages will be pro-rated to seedsmen and breeders upon written request addressed to C. E. Peterson, USDA, ARS, Department of Horticulture, University of Wisconsin, Madison, WI 53706 before September 1, 1984. _______________________________________       ________________________________ Director                                      Date California A.E.S. _______________________________________       _______________________________ Director                                      Date Florida A.E.S. ______________________________________        _______________________________ Director                                      Date Agricultural Research Service

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