Simon: Release: HCM

UNITED STATES DEPARTMENT OF AGRICULTURE                  AGRICULTURAL RESEARCH SERVICE                     WASHINGTON, D.C.  20250                               and                    THE CALIFORNIA and FLORIDA                 AGRICULTURAL EXPERIMENT STATIONS         RELEASE OF HIGH CAROTENE MASS CARROT POPULATION The United States Department of Agriculture, Agricultural Research Service, and the California and Florida Agricultural Experiment Stations, announce the release of a carrot population to be used as a germplasm for developing improved, high carotene genotypes, and for genetic and physiology research.  High Carotene Mass (HCM) was derived from the F1 hybrid [(Kokubu x B2158)F4] x [(B3O79 x Imperial Long Scarlet)F3] made in 1974.  Both parents in this hybrid were constructed to combine the Alternaria resistance of the Japanese cultivars Kokubu (PI 261648) and Imperial Long Scarlet with the root shape and color desirable for U.S. production found in B2158 and B3079.  B2158 was derived from an open pollinated synthetic population and was released July 20, 1976.  B3079 was developed from the cross B8549 x B5931.  The (Kokubu x B2158)F4 parent is a sister line to B8080 which is described in a release announcement of August 4, 1983. The potential for developing a high carotene population from this cross was first noted in the F2 generation in 1977 which resulted from mass pollinating 5 F1 plants.  The average carotene content of the F2 generation was 222 ppm, even though the four parents contributing to HCM contained 110 to 185 ppm total carotene.  Since the F2 generation, mass selection for total carotene content has been exercised with an average gain of 25 ppm in total carotene content for each of 9 cycles of selection.  The top 10 to 20% of the plants which were evaluated for root carotene content were allowed to intermate in each generation. The current average carotene content of HCM in the F2M9 generation is now 475 ppm.  This value is more than twice that of the original F2.  Among higher plants, this is the second highest carotene content reported, surpassed only by red palm oil.  The carotene content of hybrids of HCM with a range of carrot inbreds is typically the average of carotene content of both parents.  HCM restores fertility in hybrid

combination with cytosteriles.  Seed of HCM will be pro-rated upon written request received before May 1, 1987, addressed to P. W. Simon, USDA, ARS, Department of Horticulture, University of Wisconsin, Madison, WI  53706. ____________________________________________         _____________ Director, California Agricultural               Date  Experiment Station ____________________________________________         _____________ Director, Florida Agricultural                       Date  Experiment Station ____________________________________________        ______________ Administrator ARS                                    Date

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