' / AGRICULTURAL RESEARCH CENTER
/ Hastings Research Report PR-1975-3 November 12, 1974
POTATO VARIETIES: RESISTANCE TO CORKY RINGSPOT DISEASE, RECOMMENDATIONS,
AND PROMISING SEEDLINGS J. R. Shumaker, Assoc. Horticulturist and
D. P. Weingartner, Asst. Plant Pathologist
PURPOSE: The purpose of this report is to: (i) provide grower information
concerning recommended potato varieties for North Florida emphasizing re-
sistance and susceptibility to corky ringspot (CRS) disease, and (ii) summarize
test results of two promising USDA seedlings, one of which will be grover tested
at Hastings in 1975.
VARIETY and SEEDLING TESTS: The yields, CRS disease ratings, and quality
results of 12 varieties and 5 seedling potatoes are summarized in Table 1.
Two seedlings (B7629-1 and B7200-26) and 3 varieties (Pungo, Superior, and
Hudson) have grower acceptable resistance to CRS disease. The variety Hudson
has only been tested one year under conditions favoring CRS disease. A short
descriptive list of recommended varieties follows.
I. Varieties susceptible to Corky Ringspot Disease:
'.TAGO: Standard white, medium to late maturing variety. Tubers are smooth,
well shaped, moderately high in dry matter, and produce excellent chips.
S iModerate resistance to late blight and brown rot. Has the ability to recover
well from low temperatures and excess water exposure.
LA CHIPPER: Medium maturing. Irish Cobbler type, with white skin and very white
flesh. Comparable to Sebago's yield, chip quality, and dry matter. Less dis-
ease resistance than Sebago. Poor to moderate recovery from low temperatures
and excess water.
PENN 71: Late chipping stock variety. Tubers are large, bright white, flattened,
and medium high in total solids. Excellent for chips. Yields good and recovers
well from low temperatures and excess water. Some late blight resistance but .
very susceptible to verticillium wilt. Tubers may carry poorly if harvested at
an immature stage.
WAUSEON: Early table stock variety. Tubers are smooth, round to oblong,
creamy white, and often have a slightly netted or flaky skin. Acceptable
dry matter, yielder, and chipper. Some resistance to late blight and tuber
galls caused by the root-knot nematode but susceptible to verticillium wilt
and brown rot. Good recovery from low temperatures and excess water.
RED LA SODA: A dark red skinned, attractive, fairly smooth, white fleshed,
good yielding, medium-early variety with intermediate quality. Extremely
poor chipper. Highly susceptible to late blight and poor to moderate recovery
from low temperatures and excess water.
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II. Varieties Resistant to Corky Ringspot Disease:
PUJGO: Round, white variety, recommended only where corky ringspot virus
ic: present in the soil. Acceptable dry matter and chipper and yielder.
Some late blight resistance, but highly susceptible to brown rot. Tubers
are irregular in shape and develop second growth when rainfall is unevenly
distributed. Poor to fair recovery from low temperatures and excess water.
SUPERIOR: A white, early variety for use as a table or chip stock. Tubers
are usually round with medium-deep eyc-. Tubers are high in dry matter
and produce excellent chips. It should only be planted late in the season
as it recovers poorly from adverse weather conditions. Yields from early
plantings of Superior have been low.
HUDSON: (Suggested for trial purpose). A new, late, and highly yielding
white variety from New York with golden nematode resistance. Tubers are
:'-stly round, large, and smooth. Moderate to high dry matter. Chips from
stocks gr-wn at Hastings have been acceptable, but it is generally considered
a poor cl'.pper when grown in other potato areas.
PROMISING SEEDLINGS: The yield response of two USDA seedlings (B6987-56
and B6987-29) is compared in Table 2 with their parents (Wauseon x B5141-6)
and two standard varieties (Sebago and Pungo). Seedling B6987-56 is scheduled
for local grower testing and to be named in 1975. During three years of
testing,aleiiage yield.nof.thiss.eediling have been 87 cwt/A greater than Sebago's.
It har elso been superior to Sebago in chip color and specific gravity (Table 1).
uI's tubers are almost rcur.., creamy white, and often with a slight net or flaky
sk"n. It has some resistance to late blight and tuber galls caused by the root-
knot nematode; it recovers well from low temperaturesand excess water. Seedling
36987-29 has many of the same attributes of B6937-56 except that its tubers are
slightly flattened and lower in dry matter. Advanced tests of this seedling will
be conducted in 1975. Both seedlings are susceptible to CRS.
PR-1975-3 Page 2
Table 1. Yield, corky ringspot disease (CRS) ratingE, and quality results p several potato clones selected
for advanced testing at Eastings, Florida.
Variety test 2/
ance 5/ CRS 6/
1974 Corky ringspot test/
Yield Tuber rating Tubers
size"A" External Internal with
CRS 6/ necrosis internal
CRs c/ CRS
1974 Variety test/
Yield Chip Specific
size "A" color/ gravity
/ : = Clone resistant to corky ringspot disease.
2/ Soil treatment: Preplant Telone at 8 gpa in-the-i ow.
3/ No soil fumigation.
/ Soil treatment: Preplant Telone at S gpa in--the-row + at-planting Furadan 4 lb. ai/A in-the-row.
5/ Overall tuber appearance including defects due to CRS: 0=poor; excellent.
6/ CRS ratings: 0=100.' defects or internal necrosis; 9=none, excellent.
7/ Chip color: -lean of 5 chipping determinations with l=excellent, light; 9=undesirable, dark.
PR-1975-3 Page 3
Table 2. Summary of 7 yield performance tests conducted over 3 years comparing USDA seed-
lings, 36937-5c, and 36987-29, (Wauseon x 51l'1-6) with their parents and two standard
3I ens./ 2-epsl/
year and nur er of
-Reps 2- e0s'
4-RepsL/ 4-Reps-/ 2-Reps/Mean
1/ No fumigation treatment
2/ 8 gpa Telone, pre-plant-in-the-row
3/ 8 gpa Telone, pre-plant-in-the-row + 4 lb ai/A Furadan in-the-row at planting.
4/ Each comparison determined by the number of tests in which a clone and Sebago were both entered.
PR-1975-3 Page 4
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