| MICHIGAN AGRICULTURAL EXPERIMENT STATION|
MICHIGAN STATE UNIVERSITY
East Lansing, Michigan
May 1, 1963
NOTICE TO SEEDSMEN REGARDING RELEASE OF CARROT
INBRED LINES MSU 1558 and MSU 3489
The Department of Horticulture, Michigan Agricultural Experiment Station
announces the release of two inbred carrot lines for use in production of the
Fl hybrid: MSU 1558 x MSU 3489. The inbred seed parent, MSU 1558 is a male
sterile of the petaloid type and both the sterile (1558S) and maintainer (1558M)
will be distributed. MSU 3489 is a pollen fertile line to be used as male pa-
rent in producing the Fl hybrid. The official naming and release of this Fl
(MSU 1558 x MSU 3489) or others involving these lines will be delayed until
foundation stocks of the inbred parents are increased. The inbred releases
are made at this time to permit seedsmen to gain experience with the lines and
to build up foundation stock.
MSU 1558 produces a slightly tapered, stump root with a smooth dome-shaped
crown. Root color is acceptable except for some green color in the core. Sol-
uble solids average was 7.2% in roots grown at MSU Muck Farm. It was derived
from a cross of a selected plant from Long Chantenay and a petaloid male ste-
rile derived from wild carrot by Dr. H. M. Munger of Cornell University. The
petaloid sterile was sent to Michigan State University by Dr. Munger in 1957
under the number, 56-11-6 x 56-36-2. The wild-carrot petaloid had been back-
crossed twice to selections from domestic carrots. The original seed from Dr.
Munger produced 6 petaloid steriles and 2 fertiles in the greenhouse at East
Lansing. A petaloid segregate was crossed to a plant from the S2 line,
MSU 1558. The sterile:fertile ratios in F1 and subsequent generations were as
follows: 31:0 in Fl, 46:0 in BCl, 45:0 in BC2 and 169:0 in BC3. The BC3 in-
volved a 9-plant mass under a 6' x 6' cage. The other backcrosses were to
single plants. The BC3 seed, already progeny tested, is the stock being re-
leased along with the S5 massed maintainer from the same cage. Additional
large populations are being progeny tested in the field in Michigan and Cali-
fornia. Seedsmen receiving seed will be notified immediately if fertile se-
gregates appear in the field tests of 1558S.
MSU 3489, also derived from Long Chantenay, produces a tapered, stump root
with dome-shaped crown and exceptionally good exterior and interior color.
Green pigment is absent from shoulders and core. Roots grown at MSU Muck Farm
average 6.5% soluble solids. The seed being released is a mass of S3 plants
selected for pollen fertility. It has been used successfully in hybrid seed
production in the field and greenhouse but because of sparse pollen production,
a relatively high male:female ratio may be required in hybrid production with
The Fl hybrid, MSU 1558 x MSU 3489, was tested at the MSU Muck Farm in
1961 and 1962. It produces a smooth, well colored, slightly tapered stump root
averaging 7.0 inches in length. It is mild flavored, both raw and processed.
In a commercial processing trial preparation costs were lower then for strains
of Chantenay and the product was acceptable from the standpoint of palatability.
In mechanical harvesting, it was noted that there was some breaking of tops.
This was not serious in the light muck soil where this trial was grown. Under
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other conditions the weaker tops of this hybrid compared with present pro-
cessing varieties may be a serious problem for mechanical harvesting. This
and other characteristics of the Fl will be more fully evaluated this year.
MSU 1558 and MSU 3489 are released with the following understanding:
1. These lines will not be used in commercial production of hybrid
seed, other than those authorized by the releasing agency until
after January 1, 1966. After that date the lines will be con-
sidered fully released and available for use without further ap-
2. Any hybrid named by the Michigan Agricultural Experiment Station
must be sold only under that name.
3. The hybrid carrot seed producer will inform the Michigan Agriculture
Experiment Station of the extent to which these inbreds are used in
commercial hybrids. In complying with this stipulation the seed
producer is not required to identify complete parentage of hybrids
in which one of these lines in involved.
4. Any agency accepting seed under this agreement will thereby bind
itself to the above stipulations. The Michigan Agricultural Ex-
periment Station reserves the privilege of refusing, for an inde-
finite period, additional releases to any agency failing to observe
Seed of the pollen sterile (MSU 1558S), the maintainer (MSU 1558M) and
the pollen parent (MSU 3489),produced under screen isolations in 1962, will
be distributed to carrot seed producers who make a request in writing to the
Department of Horticulture, Michigan State University, East Lansing, Michigan
on or before May 15, 1963.
C. E. Peterson
Department of Horticulture
Michigan State University