Greenhouse tomato cultivar trials in Connecticut, 1999-2002

18 Pages·2003·0.6 MB·English

by  Gent, Martin P. N

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Connecticut
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Greenhouse
Agricultural 5
Tomato
Cultivar
Experiment
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Trials in
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Connecticut
New Haven
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1999-2002
1
BY MARTIN GENT
P.N.
Bulletin 990
December 2003
SUMMARY
Vegetable growers produce tomatoes in greenhouses to capitalize on the demand by consumers
for fresh and native vegetables with improved taste and nutritive qualities. Hydroponics is a production
technique that appeals to consumers, in part because vegetables can be grown without use ofpesticides.
This report compares the yield characteristics for 21 cultivars ofgreenhouse tomato grown using rock-
wool, an inert root medium used in hydroponics.
Total yield from a 3-month picking varied from 10 to 16 pounds per plant. Cabernet, an open-
pollinated beefsteak cultivar, had the highest total yield, but four other beefsteak cultivars had yields
indistinguishable from Cabernet. Fruit size varied from 7.5 ounces for Nicklow 102, down to about 3
ounces for Cronos and Dynamo. Quest, a beefsteak type, had the best yield ofmarketable fruit, nearly
10 pounds per plant, followed by Buffalo, Match, Mississippi and Trust. All these were beefsteak
cultivars with a uniform ripening characteristic. Most cultivars had a marketable yield in the range of6
to 8 pounds per plant. Cronos and Tradiro were the only cluster types with similar marketable yields.
Cracks tended to develop in the skin oflarge fruit. Although Cabernet, Jet Star, and Nicklow 102 had
higher yields and larger fruit than Quest, their marketable yield was lowered by a substantial number of
fruit with cracked skin. Quest and Mississippi did not follow this trend, in that they had large fruit but a
relatively low fraction with cracked skin. Cronos and Tradiro had high marketable yields because they
did not suffer from green shoulder, or fruit too small to be marketable, defects that were common in the
other cluster types in this trial. In general, the ranking among cultivars for total yield, market yield, and
fruit size remained the same from year to yearin this 4-year trial.
The best yields and most constant rate ofproduction were achieved when seeds were germinated
in late January and transplanted into the greenhouse in early March. Tomatoes commenced to ripen in
late May. The fruit ripened only slightly earlier when planting was a month earlier, and later planting
reduced yield and fruit quality. Some aspects ofrock-wool culture differed from that for plants grown in
soil or peat-lite mix. Rock-wool should neverbe allowed to run dry, because the concentration of
nutrients in the remaining solution increases to the point that it is deleterious to fruit size and quality.
The rock-wool root medium tends towards a basic pH when plants are fed nitrate nitrogen, because
rock-wool has little buffering capacity. Thus, acid must be added to the nutrient solution to maintain a
pH 5.6 to 6.6. With these precautions, the yields ofhigh-quality tomatoes using rock wool can equal or
exceed that for plants grown in soil or other growing media.
GreenhouseTomato Cultivars
Greenhouse Tomato Cultivar Trials in Connecticut 1999-2002
By Martin Gent
INTRODUCTION than clustertypes (Hochmuth etal 2000). The latter
generally have smallerfruitof3 to4ozcompared to 6 to
Fresh and nativevegetables arein demandby 8 ozforbeefsteaktypes. Thecultivar 'Trust' is a
consumersfortheirimprovedtaste and nutritivequalities. beefsteaktype thatis recommended in nearly all
Theycommandhighprices outofseason. Tocapitalize on production guides. Itis the mostwidely usedcultivarfor
this demand, many vegetablegrowers inthenortheastUS greenhouse production in theUSA. Someoldercultivars,
sell atretail tothelargepopulation thatresides neartheir such as 'Tropic' and 'Jumbo' are still recommended in
farms. Theyuseplastic shelters orgreenhouses to the south (Dickerson 1998, Koske et al 1998). However,
promoteearliness, extendthedurationofharvestand the newestreleases grown undermodemcultural
allow productionoffrostsensitive vegetables outsidethe conditions yield morethan 'Tmst' (Rorabaugh andJensen
field-growing season. Connecticut was amajorproducer 2001). There are awide variety ofothercultivars
ofgreenhousetomatoes until the 1960s (Wittwerand suggestedin various production guides (Precheur2003,
Honma 1979), when the energyrequirements ofaheated Oregon 2002, and Snyder2001).
greenhouse and the risingprice offuel almosteliminated
greenhouse vegetableproduction in the northeast. There is avariety ofgeneral information
However, therehas been aresurgence ofgreenhouse availableconceming commercial greenhouse tomato
tomatoproductionoverthe last20years, related toan production in the formofbooks (Blometal 1989,
increaseindirectretail to consumers fromfarm stands. Wittwerand Honma 1979), orvegetable production
Currently, more than 40farmers grow out-of-season guides that are now often found as WEB pages
tomatoes ingreenhouses in Connecticut. Peppers, (Dickerson 1998, Snyder2001, Oregon 2002). There is
cucumber, lettuce, and edible herbs are also producedin also information specific toproduction using hydroponics
WEB
greenhouses on asmall scale. in bookform (Resh 1995) and as pages (Ells etal
1991, Jensen and Rorabaugh 2001). Forinformation
Modem greenhouseproduction methods differ specific to greenhouse constmction andoperation see
fromthoseof40 years ago. In the 1960s, plants were Aldrich and Bartok 1994, andHanan et al 1979. Another
typically grown in glass-covered greenhouses. These useful resource on the intemetis alistofreferences to
heavy-duty structuresoffered more shade, andsidewall otherpublications thatdeal with various aspects of
plus ridge vents offeredmore ventilation, than the current greenhouseproduction (Donnell 2001, Peet 1999).
generation ofplastic coveredgreenhouses. In thecurrent
day, plants are typically grown in single-span hoop- Becauseboth cultural methods and available
houses coveredwith adoublelayerofpolyethylenefilm. cultivarshavechangedsubstantially in recentyears, itis
This designrequires little superstructure, andthefilm is notclearwhichcultivars oftomato are mostappropriate
cheapenough tobe replacedevery 2 to 3 years. Fan- forgreenhouseproduction in Connecticut, orforusein
forced ventilation is often used along thelength ofthe hydroponics. This reportpresentsdatafor21 cultivarsof
house. Thus, there is greaterlightpenetration and worse tomatodeveloped forgreenhouseproduction. These
airexchange in present-day polyethylene-covered cultivars weregrown inone ormore years ofa4-yeartrial
greenhouses than in glass greenhousedesignsused in the to evaluate theiryield characteristics and suitability for
past. Whenoldercultivars weredeveloped, plants were tomato production. The tomatoplants weregrown in
typically grown in soil. Cultivars thatare mostpopular rock-wool, amediumthatonly provides support and
today weredeveloped when apeat-vermiculite mix was a aeration oftheroots. All nutrients must be suppliedin the
standard substrate forgreenhouse vegetable production. irrigation water. This methodofhydroponicsis popular
Mostrecentreleases were developed in Holland, where forcommercial greenhouse vegetable production in
plants aregrown in nutrientsolution usingrock-wool Europe. No previous trials in the northeastUS have
substrate. Thesedifferences in substrate andenvironment comparedgreenhouse tomatocultivarsgrowninrock-
changethe nutrientrequirements andtheresponseof wool.
differentcultivarsto cultural conditions.
MATERIALS AND METHODS
There areagreatnumberofvarieties orcultivars
ofgreenhouse tomato available, and new ones are Growth conditionsandculture
developedcontinuously. Cultivars bredforgreenhouse
conditions yield more than thosebred forfieldproduction Theexperimentwas conductedin thefouryears
(Anderson 1996). Beefsteaktypes generally yield more from 1999 through 2002 in greenhouses atLockwood
ConnecticutAgriculturalExperimentStation Bulletin 990
Farm, Hamden, CT(Lat. 42 NLong. 73 W). Each Both the transplanted cubes andslabs werewrapped with
greenhouse was a 14x 56 x 8 feethigh (4.4 x 17 x 2.5 m) white-on-blackpolyethylene filmtoformacontinuous
framestructureconsisting of 1.25 in steel hoops setinthe trough thatwas drained atoneend.
groundat4-ft intervals. This framewas covered with an
inflateddouble-wall4-mil clear-polyethylene cover(Type As theplants developed, theywerepmned to
703XL, Huntsman Packaging, SaltLake City UT). The maintain a single stem. The stemwas supported by a
long axis wasoriented east-west. A forced-airheater string twisted aroundthe stem and hungfromasupport
fueledwith propane and set in thenorthwestcomerof wire at aheightof7 ft (2.1 m) thatran along the length of
A
eachhouseprovidedasource ofheat. 16-infan setin each row. Atweekly intervals, suckers were removed
theoppositecomerprovidedhorizontal aircirculation to when they were 3 to 6 in. long (7 to 15 cm), andthe stem
stabilizetemperaturethroughouteach house. A7 x 8 ft was lowered using the support string, to keep thestem
(2.1 X 2.4m) doorateach endofthegreenhouses was apex atbelow orthe heightofthe supportwire. Older
opened andclosedon temperature setpoints tocool the leaves were removed ifthey lay on thefloorofthe
houseusingnaturalventilation. greenhouse afterthe stemwas lowered. Neithervibration
norothermethods wereusedto enhancepollination ofthe
Climate control setpointschangedoverthe year. flowers. When thedeveloping fruitreachedpea-size, they
In late winter andearly spring, minimum temperatures werepruned to4 or5 pertruss. Thefmits wereharvested
were 70F (21C), andhouses were ventilated in the when they ripened, when more than 75% ofthe surface
temperaturerange from78 to 84F(24 to 28C). Laterin was red. The harvests weredoneat4- to5-day intervals
the spring, minimumtemperatures were lowered to60F overaperiod ofabout90days. The total yield and
(15C) andhouses were ventilated at72 to 78F (20 to number, marketyieldandnumber, fmitsize, andnature of
24C). BeginninginJune, high sunlight intensity and defects ofthefmitwererecorded foreach sub-plotateach
warmoutdoortemperatures oftenresults in maximum picking. Marketable fmithad nocracks, rough skin, green
temperatures of95F(36C) withinthe greenhouses. shoulder, blossomendrot, irregularshape such as cat
Around mid-June, no supplemental heatwas used, andthe facing, orinsectorotherdamage, andwas at leasttwo
end doorswere removed to maximize ventilation. In 2000 ounces in size.
and 2001, aluminizedshade cloth was applied atthis time
toreducesolarradiation load by 30%. The shade cloth Insectpests werecontrolled by beneficials
was stretched across the top ofthegreenhouse. Ablack (Applied Bionomics, SidneyB.C. distributedby IPM
woven shade cloth was appliedto the south side ofeach Labs, LockeNY). Lacewing {Chrysoperla rufilabris) was
greenhouse to theheightof6ft, to shade the southrow released in atarate of0.3 persquare foot (3.2 perm^) to
and mimic the effectofaborderrow ofplants. control aphids, and apredatory mite (Neoseiulus
cucumeris) was released atarateof3 persquarefootto
Seeds were placed Va in. deepin peat-lite mix in control two-spotted spidermite. Thesereleases were
1 in. diameterpots and germinated in agrowth room begun in mid-May andrepeated three times at 2-week
operatedat72Fwith a 12-hourphotoperiod. Plants were intervals. Tomato homworm was an occasional problem.
thinnedto auniformsize aboutoneweekafter They were controlledby handpicking the worms when
emergence. After4 to 6 weeks, plants weremoved to a they became largeenough to detect. No insecticides or
production greenhouse. The rootball was transplanted fungicides wereapplied.
into the centerhole ofa4-in. rock-wool cube. Cubes
were setin styrofoamtrays and watered from abovewith Fertilization
nutrient solution atthree to fourdayintervals. Aftera
further2 to 3 weeks, whenasubstantial numberofroots Plants werewateredatleastonceaday, ormore
hademergedfromthebottomoftherock-woolcubes, the often depending on sunlight, once they were transplanted
plants were setat theirfinal spacing on rock-wool slabs. onrock-wool slabs. Each plantwas suppliedwith
The rootmedium was rockwool slabs 36 x 6 x 3 in. high nutrient solution controlled by a2-gal perhourdrip
(90 X 15 X7.5 cm) covered with whitepolyethylenefilm emitterwith apositive pressurecut-off(Netafim, Haifa,
(Grodan, Denmark suppliedby Agrodynamics, Coppell Israeldistributedby W.H. Milkowski, Stafford Springs
TX). These slabs were leveled and seton pieces of 1-in. CT). Initially, the duration ofeach watering wastwo
thickpolystyrenefoam insulationtoformacontinuous minutes, corresponding to a volume of0.12pint(57 mL).
row along the length ofthe house. The slabs were This was increasedup to 1 pint (473 mL) perwatering, as
saturatedwith nutrientsolution, andthen theplastic plants grew larger. The volumeofwaterwas chosen so
wrapping wascutacross the bottomatbothends ofthe thatbetween 5 and 15% ofthe nutrient solution leaked
slab. Two4-in. squaresofplastic coveringwereremoved fromthe slabs.
fromthetop surface andtwoplants in rock-woolcubes
wereplaced on topofeachpre-watered rock-wool slab.
GreenhouseTomatoCultivars
Plants weresuppliedwith nutrients eachtime characteristics, orbecausethey weresimilarto other
theywere watered. The nutrients were supplied inthe cultivars in thetrial.
following minimumconcentrations, inparts permillion
(mg/L): nitrate-N 105, K 140, phosphate-P40, sulfate-S Timingofplantingandproduction
50, Ca 130, Mg 35, B 1.4, Fe 3.0, Mn 1.6, Cu0.4, Zn0.4,
Mo0.1, CI 15. Theseconcentrations were achievedusing In 1999, seeds were germinatedon 18 March,
proportioners (ModelA10, Dosmatic, CarrolltonTX) that transplantedtofour-inchcubes ofrock-wool on 19April,
injectedoneofthreenutrientconcentrates. One and setatthefinal spacing on rock-wool slabs on 20May.
concentratewas acomplete fertilizer(3-15-26 tomato and Fruitbegan toripenon4July andfertilizertreatments
lettuce formula, Hydrogardens, Colorado Springs, CO). commenced on 20July, and thefinalharvestwas 27 Sept.
Theotherconcentrates werecalciumnitrate and 1999. Therewas no shade cloth on thegreenhouses. For
magnesium sulfate. Sulfuric acid was addedto the the2000 season, seeds weregerminated on 30 Dec 1999,
magnesiumsulfate solution to maintain apHbelow7.5 in transplanted to4-inchcubes ofrock-wool on4 Feb2000,
therootmedium. The nutrientconcentrations and the and setatthe final spacing on rock-wool slabs on 23 Feb.
frequency ofwatering were adjusted according toplant Fruitbegan toripen on 1 May and fertilizertreatments
sizeandlight integral, so nutrients were notdepleted, and commencedon 12 May. A 30% shadecloth was applied
adequate waterremained in theroot zone. During early tothehouseson 13 June 2000, anddoors wereremoved
fruitgrowth the nutrientconcentrations were about20% to increase ventilation. The final harvestwas 15 Aug
higherthanthose stated above, duetohigh demandby the 2000. In 2001, seeds were germinated on 8 January,
plants. Theconcentrations were lowered laterin the transplantedto4-inch rock-wool pots on 8 February, and
season toaccountformore rapidtranspirationby the setatthe final spacing onrock-wool slabs on 7 March
plants. During fruit production, the nutrient solutions for 2001. Fertilizertreatments commenced on 1 May and
someplants were supplemented to raise the fruitbegan toripen about20May. On 11 June, doors
concentrations ofnitrogen and/orpotassiumby about wereremovedand30% reflective shade cloth wasplaced
30% overtheminimumconcentrations statedabove. The overeachhouse. The final harvest was 13 August. In
nitrogen supplements included ammoniumnitrate in all 2002. seeds weregerminated on 30 January, transplanted
years except2000, and magnesiumnitrate in all years to4-inch rock-wool cubes on 26February, andplants
except 1999. The potassium supplementwaspotassium wereset atthefinal spacing on rock-woolslabs on 20
sulfatein 1999 andpotassiumcarbonate in otheryears. March. Fertilizertreatments commencedon 10May, and
fruitbegan toripen on 1 June. Heatwas turnedoffand
Cultivars thedoors wereremoved on 6 June. Shadecloth was not
appliedin2002. Pickingcontinuedto26 August.
Twelvecultivarsofgreenhouse tomato Experimentaldesign
(LycopersiconesculentumMill) weregrown in each year.
Inthe firstyear, thecultivars werechosen toinclude the Therewerefourrows of24plants running along
mostpopularcultivars, andcultivars thatrepresented a thelength ofeachhouse. Plant spacing was 2 feetwithin
wide variety ofseedsources and fruitcharacteristics. therow and 2.5 feetbetween rows, resultingin adensity
Cultivars werechosentorepresentdiverse sources or of5 square feetperplant (2.15 plants/m^). Eachofthe
breeders oftomato, cultivars thatwerepopular40years fourrows within each greenhouse corresponded to one of
agooronly recently released, cultivars with largeorsmall fourdifferent supplemental nutrienttreatments. Eachrow
fruit, and cultivars with orwithoutauniformripening hadsub-plots ofsix differentcultivars. Each sub-plot
characteristic thatprevents green shoulder. All cultivars consistedoffourplantsofone cultivar. Treatmentand
wereredwhenripe, exceptTough Boy was pink. The trial cultivarlocations wererandomizedwithin and among
didnotincludecherry orgrape tomatoes. In succeeding greenhouses andfromyearto year. A completeblockof
years, somecultivars were retainedbecause theydidwell each cultivarby treatmentcombinationrequiredtwo
inprevious years, andothers were replacedwith greenhouses. In 1999, therewere only twogreenhouses.
promising alternatives. Table 1 gives acompletelistof In otheryears, thereweretwocompletereplicateblocks
cultivars, the seed source, years in trial, andgeneral infourgreenhouses.
characteristics. Fivecultivars were grown in all four
years; Cabernet, Cobra, Dynamo, Match, andTrust.
Threecultivars weregrown in threeyears; Buffalo, Jet
star, andMississippi. Sixcultivars weregrown in two
years. Theremaining sevencultivars wereonly grownin
oneyear,eitherbecausetheyhadpooryield
ConnecticutAgriculturalExperimentStation Bulletin990
Table 1. Name, source, andfruitcharacteristicsoftomatocultivars included in this yieldtrial.
Name Source Years in trial Comments
Cabernet Holmes 4 Largefruit, mostcracked skin, high total yield
Cobra Vilmorin 4 Mediumsize, green shoulder
Dynamo Sunseeds 4 Clustertype, small fruit, mostgreen shoulder
Match DeRuiter 4 Popular, uniformripe, medlarge fruit
Trust DeRuiter 4 Popular, uniformripe, medlargefruit
Buffalo Enza 3 Mediumsize, uniformripe, goodquality
JetStar Harris 3 Largefruit, tends tocrack,high total yield
Mississippi RijkZwaan 3 Med largefruit, resistanttocracking
Alexandres Sunseeds 2 Clustertype, small fruit, mostBER
Cronos Sunseeds 2 Small, uniformripe, high quality
Nicklow 102 Nicklow 2 Largestfruit, uniformripe, tends tocrack
Nicklow 21 Nicklow 2 Largefruit, uniformripe, tends tocrack
Quest DeRuiter 2 Largefruit, highestmarketyield,poorgermination
Tradiro DeRuiter 2 Mediumsmall, uniformripe, nocracks
Capello DeRuiter Large, uniformripe, tends tocrack,hightotal yield
Dalton Enza Clustertype, smallestfruit
Parks 656 Parks Mediumsmall, few cracks, green shoulder
Pegasus Sunseeds Clustertype, small fruit, green shoulder
Perfecto DeRuiter Mediumsize, uniformripe, tends tocrack
ToughBoy Seedway Pinkcolor, small fruit, lowestyield, BER
Triton Enza Clustertype, smallestfruit, low yield
Analysis ofvariancewasconductedonthetotal potassiumsupply. As notedelsewhere (Gent2003), these
yieldaccumulated in each yearusingthe general linear nutrienttreatments generallydid notaffectyields. The
model in SYSTAT (Version 10, SPSS Inc., Richmond, yields reportedhereareaveragedoverall nutrient
CA). All 12 cultivars grown in oneyearwereincludedin treatments.
analysis. Thecultivars werereplicatedfourtoeighttimes
in sub-plots, which corresponded tovarious nutrient Yields varied fromyeartoyearduring these
treatments. Tests forthe significance ofinteractionof cultivartrials. Many cultivars werenotgrown in allfour
effects ofcultivarand nutrienttreatmentfoundno years. In orderto comparecultivars thatwerenotgrown
interactions thatwere consistentfrom yeartoyear. The in the same sequenceofyears, ayearbyyearcorrection
results presentedhererely on analysis ofmain effects factorwas generated, basedon theyields ofthefive
alone. Main effects werecultivarandnitrogen and cultivars thatweregrown in all fouryears. Forthesefive
GreenhouseTomatoCultivars
cultivars, themean value foryield, orayield-related
characteristic wasdeterminedineachyear, anddivided
by the averageoverall years. This year-by-year
correction factorwas usedas acovariate instatistical
analysis todeterminethe significanceofdifferences
betweencultivars grown in morethan one year. It was
also usedto normalize resultsforcomparisons overthe
entirefour-yeartrial.
ConnecticutAgricultural Experiment Station Bulletin 990
RESULTS morefruit with cracked skin, on anumberbasis, than any
othercultivar, and this was themain reason why ithad a
Summaryoverallyears low marketable yield. Nicklow 21 and 102, andJet Star
were cultivarsforwhich aboutathirdofthefruithad
Therewere significantdifferences between cracked skin. In contrast, only about 10% ofthe small-
cultivars in nearly all aspectsoffruityield, fruitsize and fruited varieties had cracks in the skin. Questdidnot
quality (Table2), when averagedoverthefouryears of follow this trend, in thatithad large fruitbutarelatively
thistrialusing the methodfornormalizing theyeartoyear low fraction with cracked skin. Mississippi sharedthe
variation as describedabove. Seven cultivars wereonly samebehavior, although ithadsmallerfruitthanQuest.
grown in oneyear. Six ofthese weregrown only in 1999
andone was grown only in 2000. The valuesforthese Green shoulderorunevenripeningwas theother
cultivars arelisted atthebottomofTable 2. We make no common defectoffruit. Aquarterofthefruitpicked
judgmentwhetherthe valuesforcultivarsgrown in one fromDynamo had thisdefect. Cabernet, Cobra, and
yearare significantlydifferentfromothercultivars, Alexandres wereothervarieties in which more than 10%
becausethe least significantdifference forcultivarsonly ofthefruit hadgreen shoulders. Because ofstrictjudging
grown in one yearwas much largerthan forthose grown criteria, many cultivars whichhad the uniform-ripening
in twoormore years. gene, and thus shouldhave nogreen shoulder, were
evaluated as havingbetween 3% and6% green shoulder.
Total yieldofeach cultivar, averagedoverthe There was arelatively low frequency ofblossomendrot
fouryears ofthis trial, variedfrom 10 to 16poundsper with ourcultural practices. Alexandres andJetStarwere
plant. Yieldsinkilograms permetersquared are substantially differentthan theothervarieties, in that
approximatelyequal to the values in poundsperplant. about 10% oftheirfruit had blossomendrot. Formany of
Theranking foryield andfruitsizeamong cultivars was theothercultivars, only about2% ofthefruithadthis
stable overthefouryears. defect.
Cabernetwas thecultivarwith thehighest yield The fraction ofdry matteris relatedto the
overall. However, there werefourothercultivars whose soluble solids contentofthefruit. Fornearlyallcultivars,
yield was indistinguishablefromCabernet. Thecultivars this fractionrangedfrom5.5% to 5.8%. Some Sunseed
fromSunseeds; Dynamo, Alexandres, andCronos, were cultivarshad an unusually highfractionofdrymatter;
among those with the lowest yield. In part, this was 6.9% forAlexandres, and 6% ormoreforCrones and
because they were clustertomatoes, andweprunedeach Dynamo. Match andTrusthadthe lowestdry matter
truss to4or5 fruit(lessthan wouldnormally occuron a content. The cultivars withhighestorlowestdry matter
cluster). Theweightfraction ofthe fruitthatwas werethe samefrom yearto year.
marketable varied from34% to 69%. Because ofthis
variation, the rankinginmarketable yield was not
correlatedwiththatfortotalyield. Ofthecultivars grown
in morethanone year, Cronoshad thehighestfraction of
marketablefruit, whereas Cabernethad thelowest
fraction. Questhadthebestyieldofmarketablefruit,
nearly 10poundsperplantwhereasDynamoandNicklow
21 hadthe lowestmarketable yield, less than 5 pounds per
plant. Nearly all the othercultivars fell intoamidrangeof
6 to 8 poundsperplant. Tenofthefourteencultivars
grown in more than oneyearwere indistinguishablein
theirmarketable yield.
Averageweightperfruitvariedgreatly. Nicklow
102 hadthe largestfruitat7.5 ounces each. Thenext
largestfruit, 6.3 to6.7 ounces, werepickedfirom
Cabernet,JetStar,Nicklow21 andQuest. Therewere
otherdistinctsizeclasses, allthe waydown to thatofthe
Sunseed varieties, whichhad the smallestfruitatabout3
ouncesperfruit. A majorproblemwith large-fhiited
cultivars wascracks in the skin ofthefruit. Cabernethad
Table 2. Summary ofyieldcharacteristicsofeach tomatocultivargrownin any offouryearsofagreenhouse trial usingrock-
wool substrate.
GreenhouseTomatoCultivars
Yield Marketable Fruit Percentoftotal number Dry
Total Market fraction size Cracked Green Blossom matter
Name pounds/plant weight% ounce skin shoulder end rot percent
Alexandres 10.4c 5.8 be 54b 2.9 g lid 14be 11.1a 6.9a
Buffalo 13.0b 7.8 b 59ab 5.4d 24c 3d 1.5 c 5.8 be
Cabernet 16.1a 5.6c 34c 6.7 b 44a 16b 3.7 b 5.7 be
Cobra 13.3 b 6.2 be 46be 5.2d 25 c 14be 1.5 b 5.8be
Cronos 10.0c 7.1b 69 a 3.2 g 7d 3d 1.9be 6.3 ab
Dynamo 10.3 c 4.7 c 44be 3.0g 10d 25 a 0.9 c 6.0be
JetStar 15.5 a 6.9b 44be 6.3 be 33 b 2d 8.8 a 5.7 be
Match 14.4ab 7.6b 52b 6.1 e 29 be 4d 1.9be 5.5 c
Mississippi 13.9b 7.3 b 52b 6.0c 22c 9c 1.9be 5.7 be
Nicklow 102 14.7 ab 6.6 be 44be 7.5 a 35 b 3d 3.4b 5.6c
Nicklow 21 11.4be 4.8 c 41 be 6.3 be 34b 6b 2.3 be 5.9 be
Quest 14.7 ab 9.8 a 66 a 6.7b 22 c 3d 1.1c 5.6c
Tradiro 11.4be 6.7 be 58 ab 4.0e 12d 9cd 3.8b 5.6c
Trust 14.2 ab 7.4b 51b 6.1c 25 c 6cd 2.1 be 5.5 c
L.s.d. 1.8 1.5 10 0.2 8 5 1.6 0.5
Cultivars grown inonlyoneyear
Capello 15.0 5.3 35 6.0 38 3 0.7 5.5
Dalton 7.1 5.2 73 2.2 4 3 8.2 6.0
Parks 656 13.0 6.9 52 4.4 17 18 3.8 6.3
Pegasus 9.4 4.4 46 3.5 18 17 2.5 7.1
Perfecto 14.1 4.0 27 5.3 38 3 1.6 6.1
ToughBoy 6.1 2.6 43 3.5 25 8 5.3 7.2
Triton 6.3 4.5 69 2.2 13 1 4.3 6.7
Values inthesamecolumn followedbydifferentletters aresignificantly differentatP<0.05. L.s.d. Leastsignificant
differenceatP<0.05.
Differencesbetweenyears
10 ConnecticutAgricultural ExperimentStation Bulletin990
Thetiming offruitproductionvariedamong the differencein fruitsize, theincidenceoffruitwith
years (Figure 1). In 1999, theplanting was late, the cracked skin was greaterin 2001 than2000, 21 and 15%,
summerwashotandsuimy, andnoshadecloth was respectively. Nevertheless, this was amuchlower
appliedon thegreenhouses. The tomatoes didnotbegin to incidenceoffruitwith crackedskin thanin 1999. The
ripenuntil mid-July. Therateofproductionwasslower fractionoffruitwithgreen shoulderorblossomendrot
than inotheryears. Therateofproductionwas slowed wasonly5% and 1%, respectively, inboth2000and
furtherbydecreasing lightintensity in September. The 2001.
environmentin2000differedfromthatin 1999. Spring
waswarmandsunny and summerwas cooland wet. A Differenceamongcultivarswithinyears
30% shadeclothwas applied tothehouses anddoors
wereremovedtoincreaseventilation. Fruitbegan toripen In 1999, thehighest-yieldingcultivars only
earlierin2000thanin anyotheryear. Howevertherateof produced 11 poundsperplant. Cobra, Trust, and Buffalo
earlyproductionwasnotasrapidas inlateryears. Spring hadthehighestmarketableyield. Fruitsizeofthe
wascool andsnowyin 2001,butsummerwas warm. cultivars fellinto twoclasses, those with fruitweighing
Shadeclothwasapplied in 2001. Thefinal yieldin 2001 morethan4.8 ounces and those less than 3 ounces. The
wassimilartothatin2000,buttherateofproduction highestincidenceoffruitwithcrackedskin wasobserved
differed throughouttheseason. Therewas negligible yield in 1999. ThecultivarsCabernetandMatchhadthemost
inMaybuttherateofproduction in Junewas fasterthan cracked skin. Thehighestincidenceofgreen shoulder
in2000. In2002, early springwascool andcloudy, but alsooccurred in 1999. Blossomendrotwasworsethan in
the sununerhadan averagetemperature. Earlyyield was otheryears,particularly forPegasus whichhad26%
delayedbylatergerminationandtransplantingthanin blossomendrot. Fruitdrymatteras afractionoffresh
2000or2001, andby an early-seasonproblemwith weightwashigherthanotheryears. PegasusandTough
ethylenepoisoning, whichcausedthefirstflowersof Boyhadmore than7% drymatter, compared to less than
manyplantstoabort. However, therateofproductionin 6%dry matterinmostcultivars.
July andAugustwasfasterthan inanyotheryear.
Cabernethadthehighestyield in 2000, and
Thehighestyields andfruitsizes wereachieved Match andJetStarwerethe nexthighestyielding
in 2002 (Table3) when averagedoverallcultivars grown cultivars. Cobra, Dynamo, Alexandros andNicklow 21
in oneyear. Inpart, thiswasbecausenoshade wasused hadthelowestyield. Cabernethadthelargestfruit;
andpicking wasextendedtotheendofAugustin 2002. In Dynamo and Alexandroshadthesmallest. Alexandros
part, itwasbecausethehighest-yieldingcultivarsfrom hadthehighestdry matteroverall. TrustandNicklow 21
previous years weregrownin 2002. Thepercentageof hadthelowestdry matter. Ingeneral, acidity, and
fruitthatwasmarketable wasgreaterthanin 1999, the composition ofcationssuch as K, CaandMgin thefruit
otheryearin which tomatoes wereproducedin a onafresh weightbasis, scaledaccordingtodry matteras
greenhousewithoutshade, butthe marketpercentagewas afraction offresh weight(datanotshown).
lessthanin2(X)0or2(K)1,whenplants weregrownunder
30% shadeclothduringfruitproduction. Thepercentage Cabernethadthehighestyieldin 2001,butit
offruitwith crackedskin in2002wastwo times thatin alsohadthe mostcracked skin andlowestmarketable
2000,butless than thatin 1999, inpartduetothe percentage (Table6). Cronoshadthehighestmarketable
superiority ofthecultivars selectedin2002. The percentagebutsmallfruit. Nicklow 102 and21, Quest
incidencesofgreen shoulderandblossomendrotwere andCabernethad thelargestfruit. Cobrawas intermediate
higherin2002, than inyearswhenthegreenhouses were in fruitsize. Dynamoand Alexandroshadthelowestyield
shaded,butlessthan in 1999.Thefractionofdrymatter andthe smallestfruit. Questhad thehighestmarketable
inthefruitwaslowestin2002, andthusdidnotseemto yield,butitwas notsignificantly greaterthanMississippi,
berelatedto shadingthegreenhouse. Match, TrustorNicklow 102. AlexandrosandDynamo
hadan incidenceofgreen shouldergreaterthan 10%.
In2001, the averageweightperfruit, 5.8 ounces, Alexandroshadveryhighdry matter, 7.4%. Allother
was much largerthan thefruitpickedin 1999 and2000 cultivars, exceptCronos, hadless than6% dry matter.
(Table4). Thecultivarsthatweregrowninevery year Alexandros andJetStarhadthe mostblossomandrot, but
showedthis trendfromyeartoyearinfruitsize, withfruit theincidencewas 5% orless.
aboutoneouncelargerin2001 than in2000. Becauseof