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United States Department of Agriculture

Agricultural Research Service

Simon: Release: HCM
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                    WASHINGTON, D.C.  20250


                   THE CALIFORNIA and FLORIDA


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,

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
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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

Last Modified: 8/10/2004