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Blossom Drop, Reduced Fruit Set, and Post-Pollination Disorders in Tomato

Authors:
Monica Ozores-Hampton at University of Florida
Monica Ozores-Hampton
Fnu Kiran
Fnu Kiran
Fnu Kiran
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Gene McAvoy at University of Florida
Gene McAvoy
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Blossom drop and reduced fruit set in tomato can seriously impact yields. Growers in Florida routinely experience such problems and inquire about the cause and possible preventative measures to reduce flower loss and improve yields. The problem can be frustrating and difficult to manage in some situations. This 6-page fact sheet was written by Monica Ozores-Hampton, Fnu Kiran, and Gene McAvoy, and published by the UF Department of Horticultural Sciences, July 2012.
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HS1195
Blossom Drop, Reduced Fruit Set, and Post-Pollination
Disorders in Tomato1
Monica Ozores-Hampton, Fnu Kiran, and Gene McAvoy2
1. This document is HS1195, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and
Agricultural Sciences, University of Florida. Original publication date July 2012. Visit the EDIS website at http://edis.ifas.u.edu.
2. Monica Ozores-Hampton, assistant professor, and Fnu Kiran, biological scientist, Horticultural Sciences Department, UF/IFAS Southwest Florida
Research and Education Center, Immokalee, FL 34142; and Gene McAvoy, county Extension director and regional vegetable extension agent, UF/IFAS
Hendry County Extension Service, LaBelle, FL 33975.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to
individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national
origin, political opinions or aliations. U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A&M University Cooperative
Extension Program, and Boards of County Commissioners Cooperating. Thomas A. Obreza, Interim Dean
Blossom drop and reduced fruit set in tomato can seriously
impact yields. Growers in Florida routinely experience such
problems and inquire about the cause and possible preven-
tative measures to reduce ower loss and improve yields.
e problem can be frustrating and dicult to manage in
some situations.
Tomato owers are complete owers in that they have both
male (stamens) and female (pistil) parts within the same
ower (Figure 1). e yellow stamens wrap around the
greenish pistil in the center of the ower (Mills 1988). e
stamen has two parts: lament and anther, and the pistil has
three parts: ovary, style, and stigma (Figure 2). e style is
the long stalk that reaches up to the bumpy, sticky stigma,
which extends beyond the surrounding stamens. Tomatoes
are self-pollinated at the rate of 98% or more. Pollination
occurs primarily between 10 a.m. and 4 p.m. (Levy, Rabi-
nowitch, and Kedar 1978). Tomatoes need biotic or abiotic
agents to assist in pollination.
Figure 1. Reproductive features of tomato ower. Left: female pistil.
Center: open tomato ower. Right: male stamens.
Credits: Monica Ozores-Hampton Figure 2. Tomato ower structure
Credits: Carlos Ozores
2
In open-eld production, pollination is accomplished by
wind. Tomato owers hang down (Figure 3), and anthers
are located above the stigma. e pollen is released and
falls downward onto the stigma. Insect pollinators are not
important for pollination of tomatoes grown in open-eld
production (Levy, Rabinowitch, and Kedar 1978; Ozores-
Hampton and McAvoy 2010).
In greenhouse production, where plants are protected from
the wind, growers used to mechanically shake individual
ower trusses or entire plants to stimulate the release of
pollen. However, the predominant means of accomplishing
pollination now is through the use of bumble bees. e
bumble bee sonicates for pollination, meaning it vibrates its
wing muscles without ight. is causes the whole ower to
vibrate, and a cloud of pollen is released onto the bee’s body
and onto the stigma at the same time.
Blossom drop is dened as the loss of owers (Figure 4).
Several factors, usually related to some type of stress, can
cause tomato plants to drop their blooms. e stress may be
either nutritional, environmental, or a combination of the
two. However, anything that interferes with the pollination
and fertilization processes may result in ower loss (Levy,
Rabinowitch, and Kedar 1978; Mills 1988; Ozores-Hampton
and McAvoy 2010). Without pollination, which stimulates
fruit set, the owers die and drop. is condition can
aect tomatoes, peppers, snap beans, and other fruiting
vegetables. In tomatoes, blossom drop is usually preceded
by the yellowing of the pedicle. Tomato owers must be
pollinated within approximately 50 hours or they will abort
and drop o. is is about the time it takes for the pollen
to germinate and travel up the style to fertilize the ovary at
temperatures above 55°F.
Potential Causes of Blossom Drop
e primary causes of blossom drop in tomatoes are
environmental (e.g., temperature and relative humidity
[RH]) or cultural (e.g., lack or excess of nitrogen [N] fertil-
ity). Secondary causes can include lack of water, reduced
or extended light exposure, excessive wind, insect damage,
foliar disease, excessive pruning, or heavy fruit set.
Primary causes of blossom drop
Temperature: Tomato plants drop their owers under
extreme temperature regimes, such as high daytime tem-
peratures (above 85°F), high nighttime temperatures (above
70°F), or low nighttime temperatures (below 55°F) (Table
1). Optimal growing conditions for tomatoes are daytime
temperatures between 70°F and 85°F. While tomato
plants can tolerate more extreme temperatures for short
periods, several days or nights with temperatures outside
the optimal range will cause the plant to abort owers and
fruit and focus on survival (Mills 1988). Temperatures
over 104°F for only 4 hours can cause the owers to abort.
If nighttime temperatures fall below 55°F or rise above
70°F, or if daytime temperatures rise above 85°F, the pollen
becomes tacky and nonviable, preventing pollination
from occurring and causing the blossom to dry and drop
(Chester 2004; Levy, Rabinowitch, and Kedar 1978; Mills
1988; Ozores-Hampton and McAvoy 2010).
Low temperature: Low temperatures interfere with the
growth of pollen tubes, preventing normal fertilization. e
pollen may even become sterile, which causes blossoms to
drop.Tomato fruit do not set until nighttime temperatures
are above 55°F for at least two consecutive nights (Chester
2004; Ozores-Hampton and McAvoy 2010).
High temperature: Sustained high temperatures, especially
at night, rapidly deplete the food reserves that are produced
in the tomato during the day. e result is sticky pollen,
Figure 3. Open tomato blossoms hanging downward direct the pollen
from the anthers to the stigma.
Credits: Monica Ozores-Hampton
Figure 4. Blossom drop on tomatoes, January 2010, Immokalee, FL
Credits: Monica Ozores-Hampton
3
altered viability, and poor or no pollination. Ultimately,
the blossom dries and falls o. Female ower parts can
also undergo morphological changes, such as drying of the
stigma (Mills 1988; Ozores-Hampton and McAvoy 2010).
Relative humidity: e ideal RH for tomato growth and
development ranges between 40% and 70%. Relative
humidity plays a major role in pollen transfer. If RH is
lower than the optimal range, it interferes with pollen
release because the pollen is dry and unable to stick to the
stigma. If RH is higher than the optimal range, the pollen
will not shed properly (Mills 1988; Ozores-Hampton and
McAvoy 2010).
Nitrogen: High or low application rates of N fertilizer can
cause blossom drop. High rates of N encourage the plant
to produce excessive vegetation at the expense of fruit
set. Low N produces spindly vines with low food reserves
that cannot support a tomato crop (Chester 2004; Levy,
Rabinowitch, and Kedar 1978; Mills 1988; Ozores-Hampton
and McAvoy 2010).
Secondary potential causes of blossom
drop
Low or high soil moisture: Tomatoes have deep roots that
can penetrate up to 5 feet. Low soil moisture stresses and
weakens the plants. e root zone should be kept uniformly
moist throughout the growing season to develop a large
root system and reduce plant stress (Chester 2004; Ozores-
Hampton and McAvoy 2010).
Heavy fruit set: When a tomato plant has produced a large
number of blossoms, the resulting fruits compete for the
limited food supplied by the plant. e plant will automati-
cally abort some owers. Once the initial crop is harvested,
the problem should subside as the plant’s nutritional status
comes back into balance (Levy, Rabinowitch, and Kedar
1978; Mills 1988; Ozores-Hampton and McAvoy 2010).
Wind/pruning: Excessive wind can desiccate owers and/
or physically knock them o, reducing fruit set. Excessive
pruning can reduce the amount of energy the plant pro-
duces and thus can reduce ower production and fruit set.
Light: Lack of sucient light or extended exposure to light
can reduce fruit set.
Insect damage or disease: Growers should use adequate
cultural practices to control insects and diseases. Fungal
diseases—such as botrytis, heavy bacterial spot, or bacterial
speck pressure—have a negative eect on fruit set.
Hormones and Tomato Fruit Set
Hormones are natural organic compounds produced by the
plant, which regulate responses, such as bud development,
root growth, and fruit setting. Hormones can also be
produced articially and applied to regulate plant growth.
Hormone treatments can be eective during periods of
low nighttime temperatures, but the resulting fruit may
be seedless, of poor quality, and suer from puness and
blossom-end scar (Minges and Mann 1949). However,
favorable results were obtained when hormones were ap-
plied with hand sprayers directly on the owers rather than
to the whole plant (Chen and Henson 2001). Whole-plant
application can result in plant injury. Hormone treatments
do not increase total marketable yields of tomatoes but
can shi a portion of the yield to earlier in the season (by
increasing fruit size). Normally, one application at owering
and another application 15 days later produce improved
ower and fruit set (Chen and Henson 2001). ere are
many hormones and nutritional products commercially
available that may increase tomato blossom and fruit set,
but generally these products do not produce consistent
results. Currently, the UF/SWFREC Vegetable Program is
testing commercially available products that may have an
eect on tomato and pepper ower and fruit set in growth
chambers under high and low temperatures and RH.
How to Control Tomato Blossom
Drop
1. Grow varieties suited to the climate, such as varieties with
greater heat-setting ability
2. Use recommended N rates
3. Water deeply during dry weather
4. Control insects and diseases
Under high temperatures and low RH conditions: Under
controlled production situations (greenhouses), direct a
gentle spray of water at the blossoms twice during a hot
day to improve ower set when daytime temperatures
range between 90°F and 100°F and below 75°F at night.
e evaporating moisture lowers the temperature, raises
the humidity, and jars the pollen loose, thereby improving
ower set. If daytime temperatures exceed 100°F and
nighttime temperatures exceed 75°F, this technique is not
eective.
Under high temperatures and high RH conditions:
Watering the foliage is not recommended, especially when
fungal diseases are present.
4
Post-Pollination Disorders
Catface: is condition involves malformation and scarring
of fruits, particularly at blossom ends. Aected fruits are
puckered with swollen protuberances and can have cavities
extending deep into the esh (Zitter and Reiners 2004).
Causes: Possible causes include extreme heat, cold weather
with nighttime temperatures 58°F or below at owering,
drought, high N levels, or herbicide injury spray. Tomato
varieties with very large fruits are more susceptible (Olson
2009).
Control: Avoid setting transplants too early in the season,
grow catface-resistant varieties, and avoid herbicide injury.
Zippering: is condition is characterized by the presence
of brown tissue (resembling a zipper), usually running
from the stem end to the blossom end and caused by
abnormalities during early ower development (Cox, Tilth,
and Coolong 2011; Zitter and Reiners 2004).
Causes: is condition is the result of an anther remaining
attached to newly forming fruit. It is also associated with
incomplete shedding of ower petals when the fruit is
forming. It may sometimes be attributed to high humidity.
In cooler weather, parts of the ower may adhere to the
developing fruit and result in zippering (Olson 2009).
Control: Select varieties that are not prone to zippering.
Puness: is condition is characterized by fruit that ap-
pear bloated, at sided, or angular, leading to oddly shaped
fruit. e locular gel (the liquid that surrounds the seeds)
fails to ll the fruit’s inner cavity, resulting in a fruit with
attened sides that lacks rmness (Cox, Tilth, and Coolong
2011; Olson 2009).
Causes: is condition can be caused by incomplete
fertilization or seed development due to cool temperatures
or, under greenhouse production, by the lack of vibration
or shaking, which assists in releasing the blossoms’ pollen.
Other factors, such as low light or rainy conditions, high N
or low potassium, may also contribute to puness.
Control: Ensure adequate growing conditions and plant
nutrition.
In South Florida, tomatoes are planted continuously
between August and February. Tomato growing seasons are
typically dened as fall, winter, and spring, with planting
dates between 15 Aug. and 15 Oct., 16 Oct. and 15 Dec.,
and 16 Dec. and 15 Feb., respectively (Ozores-Hampton
et al. 2006). Based on planting season, the length of the
growing season averages 18, 20, and 16 weeks for fall,
winter, and spring, respectively. Historical temperatures
(average +/- standard deviation in °F) from a weather
station located in Immokalee, FL, are 79.6 +/- 1.5, 69.0 +/-
4.4, and 67.4 +/- 6.2 for fall, winter, and spring, respectively.
Hence, restrictions in marketable tomato yields in the fall
planting season are primarily due to temperatures above
85°F during the day and 70°F during the night together
with high rainfall and RH (Figure 5a). During the winter,
temperatures below 55°F during the night oen lower
marketable tomato yields (Figure 5b). In the spring season,
Figure 5. Overview of fall, winter, and spring minimum and maximum
temperatures and tomato marketable yields in Immokalee, FL
Credits: Monica Ozores-Hampton
5
high marketable tomato yields are due to ideal temperatures
during the day and night (70°F and 85°F) (Figure 5c).
In Southwest Florida, tomato variety recommendations are
normally based on disease resistance packages, especially
with regard to resistance to soil pathogens prevalent in
the area. Perhaps breeding for heat or cold tolerance or
high RH (i.e., hot and wet in the fall and cold and dry in
the winter) is not the primary selection factor a breeder
or grower considers, but the breeding is still towards
yield under Florida conditions. Table 2 shows two variety
recommendation programs for Southwest Florida (with
and without Fusarium crown rot) (Ozores-Hampton et al.
2011).
In conclusion, temperature and RH are usually out of the
grower’s control. Sometimes the only thing a grower can do
is wait for favorable weather conditions. If weather condi-
tions are optimal and other growers are not having ower
and fruit set problems, the grower should consider cultural
causes of tomato blossom drop and poor fruit set. Selecting
a suitable tomato variety, providing adequate N fertilizer,
watering suciently, and controlling insects and diseases
will potentially ensure high tomato yields. In Florida during
the early fall growing season, growers can get around the
heat issue by selecting heat-tolerant varieties.
References
Chen, J. T., and P. Henson. 2001. “Summer tomato produc-
tion using fruit setting hormones.” AVRDC February
2001C # 01-511.
Chester, T. 2004. “Tomato harvest versus planting date.” Ac-
cessed July 12, 2011. http://tchester.org/analysis/tomatoes/.
Cox, B., O. Tilth, and T. Coolong. 2011. “Management
of non-pathogenic fruit disorders of tomato in organic
production systems.” University of Kentucky Extension.
Accessed June 29. http://www.extension.org/article/18629.
Levy, A., H. D. Rabinowitch, and N. Kedar. 1978. “Morpho-
logical and physiological characters aecting ower drop
and fruit set of tomatoes at high temperatures.” Euphytica
27(1): 211–218.
Mills, L. 1988. Common tomato disorders under desert
conditions. FS-88-60. Reno: University of Nevada Coopera-
tive Extension. http://www.unce.unr.edu/publications/les/
ho/other/fs8860.pdf.
Minges, P. A., and L. K. Mann. 1949. “Improving tomato
fruit set.” California Agriculture July: 8–12.
Olson, S. M. 2009. Physiological, nutritional, and other
disorders of tomato fruit. HS954. Gainesville: University of
Florida Institute of Food and Agricultural Sciences. http://
edis.ifas.u.edu/hs200.
Ozores-Hampton, M., and G. McAvoy. 2010. “What causes
blossom drop in tomatoes?” e Tomato Magazine 14(4):
4–5.
Ozores-Hampton, M.,G. McAvoy, S. Olson, K. Cushman,
and N. Roe. 2011. Tomato varieties for Florida — Florida
“red rounds,” plum, cherries, and grapes. HS1189. Gaines-
ville: University of Florida Institute of Food and Agricul-
tural Sciences. http://edis.ifas.u.edu/hs1189.
Ozores-Hampton, M. P., E. Simonne, E. McAvoy, P. Stansly,
S. Shukla, P. Roberts, F. Roka, T. Obreza, K. Cushman, P.
Gilreath, and D. Parmenter. 2006. “Nitrogen BMP eorts
with tomato production in Florida: Update for 2005-2006
season.” Proc. Fla. State Hort. Soc. 119: 284–288.
Zitter, T. A., and S. Reiners. 2004. “Common tomato fruit
disorders.” Vegetable MD Online. Cornell University.
Accessed June 29, 2011. http://vegetablemdonline.ppath.
cornell.edu/NewsArticles/Tom_ComDis.htm.
6
Table 1. Summary of optimal temperatures for tomato-owering production and fruit set
Temperature (°F) Duration Eect
Daytime
Above 85°F Several days Flower drop and fruit abort
Above 104
°
F 4 hours Flower drop
Nighttime
Above 70°F Several days Flower drop
Below 55°F Several days Flower drop
Table 2. Tomato variety recommendations based on disease incidence, ower production, and fruit set in Immokalee, FL
Month Week 1 Week 2 Week 3 Week 4
No Fusarium crown rot
August ‘Phoenix’/FL 91 ‘Phoenix’/FL 91 ‘Phoenix’/FL 91 ‘Phoenix’/FL 91
September FL 91/FL 47 FL 91/FL 47 FL 47 FL 47
October FL 47 FL 47 FL 47 FL 47
November FL 47 FL 47 FL 47 FL 47
December FL 47/’Tygress’/SVR 200 FL 47/’Tygress’/SVR 200 ‘Tygress’/SVR 200 ‘Tygress’/SVR 200
January FL 47/’Tygress’/SVR 200 FL 47/’Tygress’/SVR 200 FL 47/’Tygress’/ SVR 200 FL 47/’ Tygress’/SVR 200
Fusarium crown rot
August ‘Phoenix’ ‘Phoenix’ ‘Phoenix’ ‘Phoenix’
September ‘Sunkeeper’/’Crown Jewel’ ‘Sunkeeper’/’Crown Jewel’ ‘Sunkeeper’/’Crown Jewel’ ‘Sunkeeper’/’Soraya’
October ‘Soraya’/BHN 585 ‘Soraya’/BHN 585 ‘Soraya’/BHN 585 ‘Soraya’/BHN 585
November ‘Soraya’/BHN 585 ‘Soraya’/BHN 585 ‘Soraya’/BHN 585 ‘Soraya’/BHN 585
December ‘Sebring’/BHN 585 ‘Sebring’/BHN 585 ‘Sebring’/BHN 585 ‘Sebring’/BHN 585
January ‘Sebring’/BHN 585 ‘Sebring’/BHN 585 ‘Sebring’/BHN 585 ‘Sebring’/BHN 585
Note: While this list includes a number of varieties currently popular with Florida growers, it is by no means a comprehensive list of all potential
varieties that may be adapted to the state under the above conditions.
... Responses to changed temperatures are more complex. For tomatoes alone, substantial reviews [2,3,5,6,8,13,31,32,35,39,41,43,46,54,61,64,66,70,73,77,78] showed that core physiological processes driving growth and development on the plant each have separate and distinct responses. Thus warmer temperatures up to an optima advance plant and fruit development, but this could be at the expense of longer term growth, yield or fruit quality. ...
... An attempt was made to correlate global temperature change levels with the yield loss from greenhouses. For different regions, the ratio of yield loss in 2022-2023 growing season versus ratio of change in total number of days with over 30 °C outside air temperature which is generally accepted as the temperature where detrimental effects start on tomatoes [3,8,13,31,39,46,61] as shown in Fig. 3. This figure includes exclusion of two extreme yield loss cases(33 and 53%) due to other possible reasons explained before. ...
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Full-text available
  • Jan 2023
Global warming is by far the most significant issue caused by climate change. Over the past few decades, heat stress has intensified into a serious issue that has a negative impact on crop production. Hence, it is crucial to modify cultivation systems to cope with this kind of stress, particularly in arid dry regions. In comparison to open-field cultivation, tomato production under protected cultivation techniques in walk-in tunnels that are suited for different farmers’ financial abilities was evaluated during the late summer season. The studied tunnels included a shaded net tunnel with natural ventilation, net tunnel with a fogging system and plastic tunnel with evaporative cooling (wet pad and fans). For the operation of fogging and evaporative cooling systems, solar energy was used as a sustainable, eco-friendly energy source. The results indicated that the solar energy system successfully operated the studied cooling systems. All studied protective cultivation techniques mitigated heat stress on tomato plant and improved the microclimate under walk-in tunnels. Moreover, evaporative cooling and fogging systems significantly increased plant leaf area, cell membrane efficiency and the contents of chlorophyll, relative water and proline compared to the net tunnel with natural ventilation. Furthermore, a marked reduction in physiological disorders was noticed. Improved physiological and biochemical parameters and limited physiological diseases led to higher fruit set, marketable fruit yield and total productivity. The percentage of marketable fruit yield increased by around 31.5% with an evaporative cooling system, 28.8% with a fogging system and 17% with a shaded net tunnel with no positive cooling as compared to an open field. However, the plants grown in open-field cultivation without protection significantly deteriorated from heat stress and had a high incidence of physiological disorders. The most incident physiological disorders were blossom-end rot, cracking, internal white tissues, sunscald, puffiness, blotchy ripening, cat face and exserted stigma. It is recommended to use a solar energy system to modify microclimate conditions through fogging or evaporative cooling under walk-in tunnels to ameliorate heat stress on grown tomato in the late summer season for higher fruit yield and fewer physiological disorders.
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... The optimal range for an abiotic factor can depend on the respective tissues or organ. Increased temperatures for example can promote vegetative growth and development of plants up to a certain level (Heuvelink, 1989), while at the same stress range reproductive organs such as pollen are already impaired or infertile (Ozores-Hampton et al., 2012;Iovane and Aronne, 2021). This observations for example have been considered in speed breeding programs. ...
Discovering Tolerance—A Computational Approach to Assess Abiotic Stress Tolerance in Tomato Under Greenhouse Conditions
Article
Full-text available
  • Jul 2022
Modern plant cultivars often possess superior growth characteristics, but within a limited range of environmental conditions. Due to climate change, crops will be exposed to distressing abiotic conditions more often in the future, out of which heat stress is used as example for this study. To support identification of tolerant germplasm and advance screening techniques by a novel multivariate evaluation method, a diversity panel of 14 tomato genotypes, comprising Mediterranean landraces of Solanum lycopersicum, the cultivar “Moneymaker” and Solanum pennellii LA0716, which served as internal references, was assessed toward their tolerance against long-term heat stress. After 5 weeks of growth, young tomato plants were exposed to either control (22/18°C) or heat stress (35/25°C) conditions for 2 weeks. Within this period, water consumption, leaf angles and leaf color were determined. Additionally, gas exchange and leaf temperature were investigated. Finally, biomass traits were recorded. The resulting multivariate dataset on phenotypic plasticity was evaluated to test the hypothesis, that more tolerant genotypes have less affected phenotypes upon stress adaptation. For this, a cluster-analysis-based approach was developed that involved a principal component analysis (PCA), dimension reduction and determination of Euclidean distances. These distances served as measure for the phenotypic plasticity upon heat stress. Statistical evaluation allowed the identification and classification of homogeneous groups consisting each of four putative more or less heat stress tolerant genotypes. The resulting classification of the internal references as “tolerant” highlights the applicability of our proposed tolerance assessment model. PCA factor analysis on principal components 1–3 which covered 76.7% of variance within the phenotypic data, suggested that some laborious measure such as the gas exchange might be replaced with the determination of leaf temperature in larger heat stress screenings. Hence, the overall advantage of the presented method is rooted in its suitability of both, planning and executing screenings for abiotic stress tolerance using multivariate phenotypic data to overcome the challenge of identifying abiotic stress tolerant plants from existing germplasms and promote sustainable agriculture for the future.
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... Plants are living organisms and have clear preferences in terms of environmental conditions (Ozores-Hampton et al. 2012;Boote et al. 2012;de Koning 1994;Sionit et al. 1987) (see also section 4.1). The variability they experience from germination also determines (partially) their ability to cope with variability in a more developed stage (Jones 2013). ...
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Growth, yield, and yield components of tomato varieties (Solanum lycopersicum L.) influenced by the application of blended fertilizers (NPS) at Jimma, South-West Ethiopia
Article
Full-text available
  • Sep 2024
The effects of blended fertilizer rates (NPS) on growth, production, and yield components of tomato varieties (Solanum lycopersicum L.) were studied utilizing irrigation facilities at Jimma University's College of Agriculture and Veterinary Medicine (JUCAVM). Strategic experiments were set up as 2x5 factorial testing in a randomized comprehensive block design (RCBD), with ten treatments combined and three replications. The treatment included five rates of mixed (NPS) fertilizer (0 kg ha-1, 50 kg ha-1, 100 kg ha, 150 kg ha-1, and 200 kg ha-1) and two tomato varieties. (Melka shola and Gelelma). Data were obtained on tomato growth, yield, and yield component characteristics. Significant results indicated the impacts of mixed fertilizers (NPS) on tomato cultivars in terms of marketable fruit weight by size group, number of total fruit yield per plant, and total fruit yield per hectare.The mixed fertilizer rate (NPS) and tomato types had substantial interaction effects on the percentage of fruit set and the number of marketable fruits per plot. association investigation revealed a positive association between tomato varieties growth, yield, and yield components. Significantly, the highest number of total fruit yield per plant (55.617), marketable fruit weight by size group (67.33 g), marketable fruit number per plot (211.67), and total fruit yield per hectare (38.183 t ha-1) were obtained at 150 kg ha-1 and 200 kg ha-1 blended (NPS) fertilizer, respectively, with the lowest at control.Melka shola produced the most overall fruit yields per plant (54.013) and per hectare (26.570 t ha-1) than Gelelma. Under Jimma conditions, 150 kg ha-1 of blended (NPS) fertilizer and Melka shola produced the highest yields. As a result, additional research should be conducted with many locations on blended fertilizer rate (NPS) mixed with tomato types.
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Assessing Processing Waste from the Sea Urchin (Centrostephanus rodgersii) Fishery as an Organic Fertilizer
Article
Full-text available
  • Nov 2022
The longspined sea urchin, Centrostephanus rodgersii, is a climate-driven pest species in south-eastern Australia. The harvest of this species is highly encouraged and in Tasmania, the existing fishery is expanding resulting in a large amount of waste that needs disposal. Research into use of waste products as inputs for organic or biodynamic farming systems can help reduce costs of disposal and keep the industry profitable; by sustaining or incrementing sea urchin harvest the industry can assist in their control. In the current study, urchin waste was dried and finely ground to a powder and applied to tomato plants in a greenhouse to examine the effect on growth and productivity. Urchin waste powder (UWP) had a mineral composition of Ca (40 g 100 g⁻¹), Mg (1.7 g 100 g⁻¹), P (0.03 g 100 g⁻¹), Fe (19.34 mg kg⁻¹) and B (38 mg kg⁻¹), a pH 8.06 in water and an Electrical Conductivity (EC) value of 7.64 dSm⁻¹. Seven different treatment rates of UWP (0.3%; 0.5%; 0.8%; 1%; 2%; 3%; 5%), were added to 10 replicate pots containing 4 kg nutrient-poor potting mix planted with tomato (Variety K1) seedlings. Plant growth, yield, quality attributes and mineral content of tomato were measured under UWP treatments with comparison against a Hoagland solution control. UWP influenced tomato growth and productivity proportional to the quantity applied, however, the Hoagland solution control had a significantly greater yield. Potting mix pH increased from 6.8 to 7 and higher available P was detected in potting mix receiving higher rates of UWP. No phytotoxic effects were detected. The highest UWP treatment matched the Hoagland control in fruit quality and nutritional composition. Processing waste from the sea urchin fishery has potential as organic fertiliser or amendment providing plant-available Ca and some microelements such as Boron.
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The ability of CROPGRO-Tomato model to simulate the growth characteristics of Thomas F1 tomato cultivar grown under open field conditions
Article
  • Nov 2021
There are few studies about the ability of CROPGRO-Tomato model to simulate tomato growth under field conditions as a function of both local weather and soil conditions. The aim of this work was to calibrate the CROPGRO-Tomato model, included in the Decision Support System for Agrotechnology Transfer (DSSAT) software, for the Thomas F1 indeterminate tomato cultivar grown under open field conditions at two locations in the Czech Republic with different soil and climate conditions. Additionally, this paper focuses on modelling the impact of compound weather events (CEs) on the growth characteristics of the hybrid field tomato variety. The genotype file, including the main parameters of crop phenology and plant growth, was adapted to the Thomas F1 indeterminate tomato cultivar. The CROPGRO-Tomato model was calibrated by inputting the soil characteristics, weather data and crop management data and then by adjusting the genetic coefficients to simulate the observed Leaf Area Index (LAI) and Above Ground Biomass (AGB ) from transplanting to harvest under the farmers' field conditions. The comparison of the LAI simulated by the model and measured under field conditions showed adequate representation with the root mean square error of 0.86 and 1.11 m ² /m ² . Although there was a good fit for LAI and AGB between the simulated and measured data during the first part of the growing season, increasing differences were found in the growing season with cool-wet and/or hot-dry thresholds of CEs.
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Update on Nitrogen BMP Efforts with Tomato Production in Florida
Article
Full-text available
  • Jul 2006
Florida tomato growers generate about $600 million of annual farm gate sales. The Florida Vegetable and Agronomic Crop Water Quality/Quantity Best Management Practices Manual was adopted by rule in the Florida Administrative Code in 2006 and describes cultural practices available to tomato growers that have the potential to improve water quality. By definition, BMPs are specific cultural practices that are proven to optimize yield while minimizing pollution. BMPs must be technically feasible, economically viable, socially acceptable, and based on sound science. The BMP manual for vegetables endorses UF-IFAS recommendations, including those for fertilization and irrigation. Current statewide N fertilizer recommendations for tomato provide for a base rate of 224 kg/ha plus provisions for supplemental fertilizer applications 1) after a leaching rain, 2) under extended harvest season, and 3) when plant nutrient levels (leaf or petiole) fall below the sufficiency range. An on-farm project in seven commercial fields was conducted in 2004 under cool and dry growing conditions, to compare grower practices (ranging from 264 to 468 kg/ha of N) to the recommended rate. Early and total extra-large yields tended to be higher with growers' rate than with the recommended rate, but these differences were significant only in one trial. The first-year results illustrated the need for recommendations to be tested for several years and to provide flexibility to account for the reality of local growing conditions. Working one-on-one with commercial growers provided an opportunity to focus on each farm`s educational needs and to identify specific improvements in nutrient and irrigation management.
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Morphological and physiological characters affecting Rower drop and fruit set of tomatoes at high temperatures
Article
  • Feb 1978
Seven tomato cultivars and lines were studied under high temperature conditions. Fruit set varied between 77.3% in the heat tolerant cv. Hotset, 62% in cv. Gamad and 16.3% in the most sensitive cv. Hosen-Eilon. The characters contributing to low fruit set were bud drop, splitting of the antheridial cone, style exsertion and reduction of the quantity and/or functionality of the gametes. Employing the above characters as criteria for selection, fruit set of an F4 line, phenotypically similar to the sensitive parent, was improved to 63.1%. Improved fruit set, 87.6%, was also obtained in an F1 hybrid between Hotset and Gamad. The importance is discussed of various easily recognizable flower components contributing to satisfactory fruit set under high temperatures and their possible use in breeding is elaborated.
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Tomato harvest versus planting date Ac-cessed
  • Aug 2004
  • T Chester
Chester, T. 2004. " Tomato harvest versus planting date. " Ac-cessed July 12, 2011. http://tchester.org/analysis/tomatoes/.
Management of non-pathogenic fruit disorders of tomato in organic production systems
  • Jan 2011
  • B Cox
  • O Tilth
  • T Coolong
Cox, B., O. Tilth, and T. Coolong. 2011. "Management of non-pathogenic fruit disorders of tomato in organic production systems. " University of Kentucky Extension.
Common tomato disorders under desert conditions. FS-88-60
  • Jan 1988
  • L Mills
Mills, L. 1988. Common tomato disorders under desert conditions. FS-88-60. Reno: University of Nevada Cooperative Extension. http://www.unce.unr.edu/publications/files/ ho/other/fs8860.pdf.
Improving tomato fruit set
  • Jan 1949
  • 8-12
  • P A Minges
  • L K Mann
Minges, P. A., and L. K. Mann. 1949. "Improving tomato fruit set. " California Agriculture July: 8-12.
Physiological, nutritional, and other disorders of tomato fruit. HS954. Gainesville: University of Florida Institute of Food and Agricultural Sciences What causes blossom drop in tomatoes
  • Jan 2009
  • 4-5
  • S M Olson
  • M Hampton
  • G Mcavoy
Olson, S. M. 2009. Physiological, nutritional, and other disorders of tomato fruit. HS954. Gainesville: University of Florida Institute of Food and Agricultural Sciences. http:// edis.ifas.ufl.edu/hs200. Ozores-Hampton, M., and G. McAvoy. 2010. " What causes blossom drop in tomatoes? " The Tomato Magazine 14(4): 4–5.
plum, cherries, and grapes. HS1189. Gaines-ville: University of Florida Institute of Food and Agricul-tural Sciences Nitrogen BMP efforts with tomato production in Florida: Update for 2005-2006 season
  • Jan 2006
  • 284-288
  • M Ozores-Hampton
  • G Mcavoy
  • S Olson
  • K Cushman
  • N Roe Florida — Florida Ozores-Hampton
  • E Simonne
  • E Mcavoy
  • P Stansly
  • S Shukla
  • P Roberts
  • F Roka
  • T Obreza
  • K Cushman
  • P Gilreath
  • D Parmenter
Ozores-Hampton, M.,G. McAvoy, S. Olson, K. Cushman, and N. Roe. 2011. Tomato varieties for Florida — Florida " red rounds, " plum, cherries, and grapes. HS1189. Gaines-ville: University of Florida Institute of Food and Agricul-tural Sciences. http://edis.ifas.ufl.edu/hs1189. Ozores-Hampton, M. P., E. Simonne, E. McAvoy, P. Stansly, S. Shukla, P. Roberts, F. Roka, T. Obreza, K. Cushman, P. Gilreath, and D. Parmenter. 2006. " Nitrogen BMP efforts with tomato production in Florida: Update for 2005-2006 season. " Proc. Fla. State Hort. Soc. 119: 284–288.