AGRICULTURAL RESEARCH CENTER
IFAS, University of Florida
Dover ARC Research Report DOV-1984-2 u Wi 983 BRARY
ABSTRACTS OF PUBLICATIONS FROM ARC-DOVER FROM 1979 TO .984
i^Vl I i I o t
C. M. Howard, and E. E. Albregts
IFA.S.. Univ. of Florida
The primary goals of the Agricultural Research Center, Dover are to: (A) develop
high yielding, disease and pest resistant strawberry varieties adapted to Florida;
(B) study the occurrence, distribution, severity, and control of diseases of
strawberries and vegetables (primarily strawberries); (C) develop information on
improved methods of fertilization and culture of strawberries; (D) add to the
worldwide body of scientific information in the above specific areas of study;
(E) cooperate with researchers in other disciplines to solve problems on straw-
berries in Florida; and (F) serve as technical resource support to County and State
agricultural extension staff.
Some of the accomplishments of the research programs at ARC-Dover during the past
16 years that the programs have been in effect are: (A) development of the straw-
berry varieties 'Florida Belle' and 'Dover'; (B) improvement in placement and types
of fertilizers used; (C) discovery of eight.new diseases of strawberries and one of
snap beans; (D) assistance with registration of two new miticides (through
cooperation with AREC-Bradenton entomologists) and three new fungicides for use on
strawberries in Florida; (E) development of methods whereby plants of California
strawberry varieties, most of which are highly susceptible to the devastating
anthracnose disease, could be produced successfully in Florida; (F) development of
intermittent irrigation to establish strawberry transplants in the fall, thereby
decreasing water and energy usage and production costs; (G) demonstration that
insufficient foliage on non-dormant plants at transplanting reduces plant growth
and early yield and occasionally the total fruit yield of strawberries; (H)
demonstration that delaying transplanting until the last of October or later or
storing plants in cooler for longer than two weeks delays fruit production; and (I)
development of information showing how much fertilizer was taken up by the straw-
berry plant during growth and fruiting and in what plant part it was stored.
Abstracts of publications and presentations at scientific meetings by ARC-Dover
researchers during the five year period from January 1979 to June 1984 are
1. Howard, C. M., and E. E. Albregts. 1979. 'Dover', a firm fruited strawberry
with resistance to anthracnose. Univ. of Fla. Expt.,Sta. Circular S-267. 5 pp.
One of the major efforts in strawberry breeding in recent years in Florida has
been, and continues to be, development of cultivars with resistance to
anthracnose caused by the fungus Colletotrichum fragariae Brooks.-Anthracnose
is a devastating disease on highly susceptible cultivars and often causes
complete loss of strawberry nursery fields when attempts are made to grow plants
of these cultivars in Florida during the summer. When plants of these cultivars
are dug from nurseries that appear to have a low incidence of disease, many of
the plants often wilt and die after transplanting.-Up to 80 percent of the
plants have been lost in individual fruiting fields by late March. 'Tioga' and
'Tufts' are presently the favored cultivars in'Central Florida, but because of
their high susceptibility to anthracnose, growers seldom try to produce plants
of these cultivars in Florida. The disease has become well established on these
cultivars in North Carolina, where central Florida growers obtain the major
portion of their transplants, and has been the cause of major economic losses
to plant producers in North Carolina and fruit growers in Florida. 'Dover' has
shown excellent resistance to anthracnose in Florida. It has generally out-
yielded all other cultivars in central Florida and has a firm fruit with
excellent shipping qualities.
2. Howard, C. M., and E. E. Albregts. 1980. 'Dover' strawberry. HortScience 15:
'Dover''is a high yielding, firm fruited strawberry (Fragaria X ananassa Duch.)
with excellent resistance to anthracnose. It has consistently shown good
performance for the fresh market in trials in central Florida. 'Dover' is
named for the village of Dover centered in the major strawberry production area
in west-central Florida.
3. Albregts, E. E., and C. M. Howard. 1982. Strawberry variety trials 1980 and
1981. Dover ARC Research Report SV-1982-1. 6 pp.
Marketable fruit yields for the 'Dover' cultivar were high both seasons. The
two breeding lines had high yields the second season but less than 'Dover' the
first season. There was some root knot nematode infestation in the two breeding
lines the first season which may have reduced yields. Total marketable yields
of 'Tufts' were less than 'Dover' both seasons and less than the two breeding
lines the second season. For the two seasons, the January yield of 'Tufts' was
less than the January yields of 'Dover' and breeding lines 77-163 and 77-169.
January yields for 'Pajaro' the second season were also fairly good. However,
'Dover' and the two breeding lines produced a greater percentage of their fruit
before April than did all other cultivars.
4. Albregts,. E. E., and C. M. Howard. 1982. Strawberry variety trials 1982.
Dover ARC Research Report DOV-1982-4. 6 pp.
January marketable fruit yields were highest for 'Dover' and breeding lines
77-163, 77-869, and 78-1268. The February yields of these same clones were also
among the highest. Early (December and January) fruit production is important
since fruit prices generally decline with time with the lowest prices coming
in April. 'Tufts', 'Douglas', and 'Pajaro' yields for January.and February were
among the lowest of all clones tested. March yields of 'Tufts', 'Douglas', and
'Pajaro' were among the highest.
5. Albregts, E. E., and C. M. Howard. 1983. Strawberry variety trials 1983.
Dover ARC Research Report DOV-1983-2. 9 pp.
January marketable fruit yields were highest for clones 80-456, 'Florida Belle',
80-1283, 77-163, 80-1232, 80-733, and 80-933. Clones 77-163, 80-733, 80-933,
and 80-1283 also gave high February yields. 'Douglas', 'Tufts', 'Pajaro',
77-869, and 80-1340 yields were low in January and February. Since fruit prices
generally decline with time, early yields (December and January) are important
for a profitable season.
Seasonal marketable yields were numerically highest with the clones 80-456,
80-1232, 80-933, 80-733, 80-991, 77-198, 77-873, and 80-1283. Seasonal yields
were numerically lowest with 'Douglas', and 'Tufts'. 'Douglas' had the lowest
percentage of its fruit rated cull while clones 80-1283, 'Dover', 80-952, and
77-873 had the greatest percent cull fruit. As noted in Table 2 most cull fruit
are harvested late in the season. The principal reason for cull fruit is small
size. The large number of fruit on some clones during the latter part of the
season Plus the high temperatures often encountered at that time result in many
small fruit. This is-especially true of those fruit ripening last in a fruiting
CULTURE AND FERTILITY:
1. Albregts, E. E., and C. 1.. Howard. 1984. Strawberry production in Florida.
Univ. of Fla. Expt. Sta. Bull. No. 841. (In Press).
A review of the production and cultural practices for strawberries grown in
Florida. Information on site selection, bed preparation, plant source and
quality, planting date, weed control, fertilization, cold protection, and
harvesting and marketing of fruit are some of the practices discussed. Nursery
production and cultural practices are also reviewed.
2. Albregts, E. E., and C. I. Howard. 1980. Accumulation of nutrients by straw-
berry plants and fruit grown in annual hill culture. J. Amer. Soc. Hort. Sci.
The accumulation of N, P, K, Ca, Mg, Fe, in, Zn, and B were determined at
transplanting, first flowering, first harvest, middle of harvest season, and
end of harvest season to ascertain the extent and the pattern of plant nutrient
uptake in strawberry (Fragaria X ananassa Duch.). The plants were grown with
the annual hill cultural system and mulched with polyethylene. More accumulation
of each element occurred during harvest than before that time. Excluding
harvested.fruit, leaves accumulated the most N, P, K, and Mg, the roots and
crown the most Fe and Zn, while the dead material accumulated the most Ca.
Harvested fruit accumulated more N, P, K, and B than did the plant. The
calculated average seasonal accumulation of the 9 elements in the plant and in
the harvested fruit during the 2 seasons in kg/ha were: K 63.1, N 58.6, Ca 30.8,
P 9.4, Mg 7.8, Fe 0.456, Mn 0.161, Zn 0.088, and B 0.077.
3. Albregts, E. E., and C. M. Howard. 1981. Effect of poultry manure on strawberry
fruiting response, soil nutrient changes, and leaching. J. Amer. Soc. Hort. Sci.
Strawberries (Fragaria X ananassa Duch.) were grown for 3 seasons on a well.
drained fine sand which received 0, 4.5, 9, 18, and 36 Metric Tons (OiT)/ha of
poultry manure.annually. Fruit yields increased eachseason with increasing
rates of manure up to 18 mT/ha. The 36 MT/ha rate caused a foliage burn during
the first three seasons which may have reduced yields. Considerable leaching
of the soluble nutrients from manure to and below the 60 cm soil depth
occurred from season to season. Analyses of saturated soil extracts indicated
that concentrations of soluble salts, K, and NO3-N increased with increasing
rates of manure at all 4 depths to 60 cm. The Ca, K, and Mg concentrations at
all 4 soil depths increased with increased manure rates and generally decreased
with depth. Organic matter content of the surface 15 cm of the soil increased
with increased manure rate. Soil pH was only slightly affected by the manure
4. Albregts, E. E., and C. M. Howard. 1982. Effect'of transplant stress on straw-
berry performance. HortScience 17 (4):651-652.
Subjecting harvested transplants of strawberry (Fragaria X ananassa Duch. cvs.
Florida Belle and Dover) to excessive wilting increased foliage loss and plant
mortality and reduced plant size and January fruit yields.
5. Albregts, E. E., and C. 1. Howard. 1984. Effects of short term cold storage and
of soil fertility during plant and fruit production on growth and fruiting of
strawberry. HortScience: (In-Press).
Strawberry plants (Fragaria X ananassa Duch. cvs. Dover and Florida Belle)
produced higher December fruit yields when stored at 20C for one week prior to
transplanting in the fruiting field rather than transplanting directly from the
nursery. A 224-50-224-kg/ha NPK rate increased 'Dover' seasonal fruit yields
over a fertilizer rate double that amount. Lowering the soil fertility level
in the nursery prior to plant harvest generally increased December fruit yields.
3. Albregts, E. E., and C. IM. Howard. 1979. Effect of bed height and N fertilizer
sources on fruiting strawberries. Proc. Soil and Crops Sci. Soc. Fla. 38:76-78.
Bed heights of 15, 22.5, and 30 cm and fertilizer sources of urea, urea-
formaldehyde, Osmocote, sludge, and sludge plus NH4N03, and NH4NO3 were
evaluated in the strawberry (Fragaria X ananassa Duch.) fruiting field for two
seasons on a well.drained fine sand. Bed heights did not significantly affect
fruit.yields but did affect the soil soluble salt levels during the second
season. The sludge fertilizer source produced highest fruit yields. Overall, the
fertilizer sources of NH4NO3 and ureaformaldehyde produced lowest yields. The
Osmocote source had highest soil levels of soluble salts, N03-N, and NH4-N
throughout.the season. The sludge source also produced high soil levels of
soluble salts, NO3-N, and NH4-N. Leaching occurred under the mulch with all
fertilizer sources but especially with the N14N03 and urea sources.
7. Albregts, E. E., and C. M. Howard. 1979. Effect of two and four row beds with
drip or sprinkler irrigation on strawberry fruiting response. Proc. Fla. State
Hort. Soc. 92:73-74.
Strawberry plants on 4-row beds produced greater yields/ha when using overhead
sprinkler irrigation than did plants on'2-row beds. Little variation in yield/
plant occurred. Fruit number/ha was greater with the 4-row beds. When using drip
The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
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