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


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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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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
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 bees 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
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
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
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
Under high temperatures and high RH conditions:
Watering the foliage is not recommended, especially when
fungal diseases are present.
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
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
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
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.
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.
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.
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.
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.les/
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://
Ozores-Hampton, M., and G. McAvoy. 2010. “What causes
blossom drop in tomatoes?” e Tomato Magazine 14(4):
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.
Table 1. Summary of optimal temperatures for tomato-owering production and fruit set
Temperature (°F) Duration Eect
Above 85°F Several days Flower drop and fruit abort
Above 104
F 4 hours Flower drop
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.
... Generally, plant reproductive stages such as flowering and fruit setting are more sensitive to temperature stress than vegetative stages [7]. A typical problem associated with temperature extremes during the reproductive stages of tomato production is blossom drop, a problem often experienced by tomato growers in Florida [8]. Although tomato is grown under a wide range of climatic conditions, they are extremely sensitive to hot and humid environments [9], which is typical of most tomato production areas in south Florida. ...
... This is because plants are generally sensitive to temperature extremes during reproductive stages [19], resulting in fewer pollen production and reduced pollen viability and fruit set [20]. This is the reason why blossom drop during tomato growing season in Florida has been primarily associated with temperature extremes [8]. Blossom drop is related to lower yield because a higher rate of blossom drop would result in fewer fertilized flowers, hence, fewer fruit number at maturity. ...
... Similarly, the increasing biomass accumulation under high temperature could not be attributed to a direct effect of the elevated temperature on tomato growth. This is because under a high-temperature induced stress, tomato fruit set is significantly reduced, resulting in a higher partitioning of resources (carbon, water, and nutrient) into vegetative biomass compared to plants under optimum temperature condition with no heat stress [7][8][9]12,20]. ...
Full-text available
Florida ranks first among US states in fresh-market tomato production with annual production exceeding one-third of the total annual production in the country. Although tomato is a signature crop in Florida, current and future ambient temperatures could impose a major production challenge, especially during the fall growing season. This problem is increasingly becoming an important concern among tomato growers in south Florida, but studies addressing these concerns have not been conducted until now. Therefore, this study was conducted to determine the impacts of the present ambient temperature conditions and planting dates on tomato productivity in south Florida. The study was conducted using crop simulation model CROPGRO-Tomato of DSSAT (Decision Support System for Agricultural Transfer) version 4.7. Five treatments were evaluated, and included AT (simulated treatment using 14 years of actual daily weather conditions at the study location) while other treatments were conducted based on a percentage (−20%, −10%, +10%, +20%) of AT to simulate cooler and warmer temperature regimes. The results suggested that under the current temperature conditions during the fall growing season in south Florida, average tomato yield was up to 29% lower compared to the cooler temperature regimes. Tomato yield further decreased by 52% to 85% at air temperatures above the current condition. Yield reduction under high temperature was primarily due to lower fruit production. Contrary to yield, both tomato biomass accumulation and leaf area index increased with increase in temperature. Results also indicated that due to changes in air temperature pattern, tomato yield increased as planting date increased from July to December. Therefore, planting date modification during the fall season from the current July-September to dates between November and December will reduce the impacts of heat stress and increase tomato productivity in south Florida.
... This is because the male function of tomato flower is generally more exposed to damage than the female one under heat stress [59][60][61]. Furthermore, Ozores-Hampton [62] indicated that stigma-drying of tomato female flower can also happen when the plants suffer from heat stress. Moreover, it was stated that the initial stages of stamen development are most susceptible to heat stress. ...
Full-text available
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.
... 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. ...
Full-text available
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.
... 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). ...
... Each crop was assigned two independent sensitivity rankings: one for changes in summer Tmax and one for changes in winter Tmin on a scale of one (low sensitivity) to four (high sensitivity) ( Table 1). Effects of both crop yield and quality were taken into account: for example, a summer heat wave may cause flower abortion and subsequent low yield in tomatoes (Ozores-Hampton et al., 2012), while in lettuce it may cause bitterness (Smith et al., 2011). An increasing winter minimum temperature would reduce the critical chilling hours required by pears, cherries, apples, and walnuts. ...
Technical Report
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This report examines and summarizes the effects increasing global temperatures are likely to have on the regional climate and sea level rise potential as they pertain to impacts on agriculture in California’s Sacramento-San Joaquin Delta. This study focuses on two climate change ramifications: increasing sea level rise and increasing temperatures. Both of these environmental pressure effects will vary by crop and location. Increasing temperatures in summer and winter seasons are likely to have potential major impacts depending on cropping type (annual vs. perennial) and sea level rise has the potential to erode and thus break a complicated and maintenance dependent levee system in the Delta leading to flooding and crop acreage losses. The reported analysis is based on worst case scenario projections for sea level rise (SLR of 1.41 meters by the end of the century) and four climate change model projections which represent CO2 emissions continuing to rise strongly through 2050 and plateau around 2100. Two projected years measuring minimum (Tmin) and maximum (Tmax) annual temperature for 2030 and 2099 are used in this study’s assessment. In summary, our results and conclusions found that reclaimed islands (many below sea level) in the central Delta are under the highest threat of maximum SLR along with their levee systems which we estimated at $50 million/year maintenance cost to most of the 847 miles of levee identified. Different crops respond in markedly different ways to temperature change; chill-sensitive perennial fruit and nut tree crops are of special concern. This study was also able to define areas of agricultural vulnerability within the Delta based on the most recent crop patterns found in 2016: summer conditions will specifically affect crops in Contra Costa and San Joaquin Counties (central Delta and lower end of southern Delta), and winter conditions will specifically affect crops in Sacramento and San Joaquin Counties (lower northern Delta and entire southern Delta). Perennial fruit and nut tree crops should attract the most attention (i.e. cherries, pears, and walnuts for this region), but heat-sensitive annual crops (asparagus, beans, corn, cruciferous crops, cucumber, herbs, lettuce, potato, rice, and wheat) are also a strong driver of vulnerability in this region. There are crops that are grown in this region that appear to (from this preliminary analysis) benefit from increasing temperatures if irrigation water (and required quality) is available: alfalfa, cantaloupe, citrus, fig, olives, many of the grains/grasses, tomatoes, and watermelon. There are other crops that lack published data on climate relationships, i.e. onions, garlic, carrots, etc. which limits our ability to assess fully. Besides suitability, crucial aspects of quality and yield for sensitive crops (i.e., wine grapes) needs to be produced to help inform future vulnerability investigations. It should be clear that more in-depth analysis to understand crop physiological constraints and agricultural economics/marketing need to be constructed to produce adaptation scenarios. A summary of key findings and potential adaptation strategies for Delta agriculture with respect to changing climate is fully addressed.
... Excessive wind can drop flowers and or physically stopped them off, reducing fruit set. Excess wind can reduce the amount of energy the plant produces and thus can reduce flower production and fruit set (Monica Ozores-Hamrton and Gene McAvoy, 2012). Some areas will likely experience decreased rainfall, leading to more extensive drought periods. ...
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Abstract In India, the production of Tomato (Solanum lycopersicum L.) varies every season and their market price also fluctuated. S. lycopersicum plants are self-pollinated. Pollination is an important ecological interaction and the first step for the sexual reproduction. Tomatoes Blossom and flower drop is a serious effect of the environmental factors. The present study was carried out during the monsoon season (October – December 2017) to the evaluate influence of abiotic factors on the production of tomato in Namakkal district, Tamil Nadu, India. During monsoon season the production of tomato was severely affected by various abiotic factors. The influence of maximum temperature has a positive correlation with tomato flower blossom and flower drop. Rainfall, Relative Humidity, and Wind have negative correlation the flower blossom and flower drop.
... In 2015, the total biomass accumulations at 95 DAT were less than those in 2014 at respective P rates (Table 2) and lower than the amount of 6000 kg ha -1 reported by Scholberg et al. (2000). Lower total biomass accumulation in 2015 was due to lower fruit biomass, which might be affected by the higher amount of rainfall at tomato fruit set stage (Ozores-Hampton and McAvoy, 2015). Liu et al. (2011b) concluded that 90 kg ha -1 of P increased processing tomato plant biomass (stem and leaf combined) by only 9% comparing with 0 kg ha -1 in acid to neutral-mineral soils with medium to high levels of Olsen extractable P. Similarly, in the present study, P rates of either 98 or 118 kg ha -1 did not result in significant increase in total biomass comparing with the rate of 0 kg ha -1 at 95 DAT in 2014 (Table 2). ...
Understanding P accumulation and partitioning is essential for improving phosphorus use efficiency (PUE) and minimizing environmental impact. A 2-yr study was conducted to determine P distribution and PUE in tomato (Solanum lycopersicum L.) production as influenced by P application rates in a calcareous soil. Phosphorus was applied at 0, 29, 49, 78, 98, and 118 kg ha–1 as pre-plant dry fertilizers. At 95 d after transplanting, total phosphorus uptake (TPU) was not significantly affected by P rates in either year. In 2014, the highest proportion of TPU was accumulated in fruits and the maximum partitioning of TPU to fruits occurred at 72 kg ha–1. A higher or similar percentage of TPU was allocated to leaves comparing with fruits in 2015, which was probably due to the higher rainfall accumulation. Positive soil P budgets occurred with P rates ranging from 29 to 118 kg ha–1 in both years. Phosphorus concentrations in surface soil and subsurface leachate increased linearly with increasing P rate. Tomato marketable yield at the first and second combined harvest was not affected in 2014, whereas the yield increased linearly and attained a plateau at 56 kg ha–1 in 2015. There were no significant differences among treatments in the total season marketable yields in either year, thus, the partial factor productivity decreased with increasing P rate. Consequently, in the calcareous soils with 37 to 51 mg kg–1 of Mehlich-3 extractable P, 56 kg ha–1 can be the sufficient P rate for tomato production.
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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.
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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In India, the production of Tomato (Solanum lycopersicum L.) varies every season and their market price also fluctuated. S. lycopersicum plants are self-pollinated. Pollination is an important ecological interaction and the first step for the sexual reproduction. Tomatoes Blossom and flower drop is a serious effect of the environmental factors. The present study was carried out during the monsoon season (October – December 2017) to the evaluate influence of abiotic factors on the production of tomato in Namakkal district, Tamil Nadu, India. During monsoon season the production of tomato was severely affected by various abiotic factors. The influence of maximum temperature has a positive correlation with tomato flower blossom and flower drop. Rainfall, Relative Humidity, and Wind have negative correlation the flower blossom and flower drop.
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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.
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.
Tomato harvest versus planting date Ac-cessed
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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
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Mills, L. 1988. Common tomato disorders under desert conditions. FS-88-60. Reno: University of Nevada Cooperative Extension. ho/other/fs8860.pdf.
Improving tomato fruit set
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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
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Olson, S. M. 2009. Physiological, nutritional, and other disorders of tomato fruit. HS954. Gainesville: University of Florida Institute of Food and Agricultural Sciences. http:// 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
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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. 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.