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United States Department of Agriculture

Agricultural Research Service

Simon: Release: B493, B9304
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Germplasm Release - Carrot Inbred Lines B493, B9304
              UNITED STATES DEPARTMENT OF AGRICULTURE
                   AGRICULTURAL RESEARCH SERVICE
                      WASHINGTON, D.C.  20250

                                with

           THE WISCONSIN AGRICULTURAL EXPERIMENT STATION
                     MADISON, WISCONSIN  53706

              RELEASE OF CARROT INBREDS B493 and B9304


The United States Department of Agriculture, Agricultural
Research Service, and with the Wisconsin Agricultural Experiment
Station, announces the release of two carrot inbreds to be used
as germplasm for developing improved genotypes and for genetic
and physiology research.

B493 was derived from a cross made in 1968 at the University of
Wisconsin between B8549 (a high-solids, Imperator-shaped inbred
from Long Chantenay) and B5931 (a dark orange inbred from
Imperator 58 used as a parent in hybrids Spartan Sweet and
Spartan Bonus).  Selection was based on improving color and
Imperator shape for eight generations beyond the F2.  Beginning
in the F2M3S5 generation, selection was made for harsh
(turpentine-like, burning) flavor, high volatile terpenoid
content, and low bisabolene content.  Fourteen sibling
populations were selected for these characteristics plus
continued lection to withstand inbreeding depression.  After
six more generations of self-pollination plus two generations of
mass pollination to increase seed supplies, B493 is in the
F2M3S11M2 generation, making it suitable as a homozygous
test parent in carrot genetic and physiology research.  B493 has
also been tested for use in tissue culture where it produces
callus and suspension cultures readily and regenerates on solid
medium or in liquid culture easily.  Sucrose predominates in the
free sugars stored in B493 roots.  Therefore B493 is rs/rs.
Volatile terpenoid content surpasses 110 ppm (less than 1%
bisabolene) whereas the carotene content of B493 ranges from 180
to 210 ppm, depending on growing conditions.  Its dark orange
color and Imperator shape make it suitable for developing
additional fresh market germplasm and commercial hybrids.  A
petaloid (anthers transformed to petals) cytosterile counterpart
("A" line) of B493 is now at BC11.

B9304 was derived from a cross made in 1972 at the University of
Wisconsin between W33 (a uniformly dark orange tapered inbred
derived from a cross between Hutchinson and Tendersweet) and
B10138 (a dark orange Danvers-shaped inbred from Danvers 126).
Dark orange color and Danvers shape was selected for four
generations beyond the F2 generation.  In the F5 generation,
selection for mild flavor, low volatile terpenoid content,
succulent texture, and high reducing sugar content was initiated
among seven sibling populations of W33xBl0l38.  After four more
generations of mass pollination, B9304 was derived from one of
these populations in the F5M5 generation.  B9304 roots have
uniformly high reducing sugar (Rs/Rs), very low volatile
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terpenoids (10-15 ppm), crisp succulent texture, Chantenay shape,
and carotene content of 90 to 125 ppm, depending upon growing
conditions.  B9304 has been tested for use in tissue culture
where it proves to be a slow producer of callus and suspension
cultures, and a difficult genotype to regenerate.  Its excellent
culinary quality makes it suitable for developing additional high
quality germplasm and commercial hybrids.  B9304 is a partially
sterile male parent.  A petaloid (anthers transformed to petals)
cytosterile counterpart ("A" line) of B9304 is now at BC7.
Seed of cytosteriles B493S and B9304S, and of their maintainers
B493M and B9304M will be pro-rated upon written requests received
before May 1, 1987, addressed to P. W. Simon, USDA, ARS,
Department of Horticlulture, University of Wisconsin, Madison, WI
53706.



_____________________________________     _______________________
Director, Wisconsin Agricultural          Date
Experiment Station



_____________________________________     _______________________
Administrator, ARS                        Date


Last Modified: 8/10/2004