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United States Department of Agriculture

Agricultural Research Service

Simon: Release: B8080
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                  UNITED STATES DEPARTMENT OF AGRICULTURE
                       AGRICULTURAL RESEARCH SERVICE

                                        and

                            THE FLORIDA AND WISCONSIN
                       AGRICULTURAL EXPERIMENT STATIONS


                        RELEASE OF CARROT INBRED LINE B8080


The United States Department of Agriculture, Agricultural Research Service,
in cooperation with the Florida and Wisconsin Agricultural Experiment Stations
announce release of the market-type carrot inbred B8080 for direct use as
a parent in hybrid cultivars and as a source genotype to use in breeding for
flavor, high carotene and disease resistance.  A high quality hybrid,
B6274 BC1x B8080, will be released as soon as pilot production and commer-
cial trials can be completed.  This line is released now to permit seedsmen
to build up a supply of stock seed and to begin testing B8080 in experimental
hybrids.

B8080 was derived from a cross, made in 1972 at the University of Wisconsin,
between plants selected from inbred B2158 and the Japanese cultivar, Kokubu
(PI 261648).  Line B2158 was released in 1976 as the pollen parent in hybrid
Candy Pack.  Kokubu was first identified as a source of resistance to
Alternaria leaf blight (Alternaria dauci) in field exposure tests at
Belle Glade, Florida in February, 1970.1/  Resistant selections from that
test, grown through the seed cycle at Madison, WI, became the source of
Alternaria resistance in crosses with B2158 and several other advanced
maintainer lines.

Roots of B8080 are 7-8 inches long, slightly tapered to a semi-blunt tip.
Color is deep orange exterior and interior with little contrast between xylem
and phloem and no tendency to develop a light cambium zone.  The orange color
extends down into the tap root.  In the seed cycle the plants are vigorous
and produce abundant pollen.  It has produced good seed yields on a wide
range of seed parents.  The development of a cytosterile companion line has
not been completed.  All of the backcross progenies have been 100% male
sterile demonstrating that B8080 is the maintainer (M) type.

In F2 and subsequent generations the B2158 x Kokubu progenies segregated
for better color and higher carotene content than either parent.  Selection
through F3 and M1 was based entirely on color and other visible character-
istics.  In the last four cycles the roots from plants having Alternaria
resistance at Zellwood, FL were selected for flavor by a simple taste test
and finally for carotene content by laboratory analysis of samples taken
from individuals roots which were then planted for seed production in breeding
plots and cages at Madison.  This selection sequence resulted in combining
good flavor with resistance to Alternaria leaf blight and high carotene
_______________
1/Field tests for Alternaria resistance were conducted by J. O. Strandberg,
University of Florida, Research and Extension Center, Sanford, FL.
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content.  Average carotene levels in roots grown in California were 190 ppm
in B8080, 85 in Imperator 58 and 66 in Scarlet Nantes.  Since there is still
significant root to root variability for carotene content the recurrent
selection program will be continued until a stable, high carotene level is
achieved.  As improvements are made new stocks will be distributed on request
to replace the original.

Breeders seed of B8080 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, 1983.







_____________________________________     ___________________________________
Director                                  Date
Florida A.E.S.




_____________________________________     __________________________________
Director                                  Date
Wisconsin  A.E.S.




_____________________________________     ___________________________________
Administrator                             Date
Agricultural Research Service


Last Modified: 8/10/2004