nation of Gr~~~6Ug~ Tomatoes

\. 1i.:'l
October, Ie)28
I'iil
,
I
nation of Gr~~~6Ug~ Tomatoes
H W. Schneck
19254
11111111111111111111111111111111
IARI
Published by the
Cornell University
Agricullural Experiment Station
Ithaca, NelV York
Received for llubI1cl1ti(lJ\
Ocwbt~r
18. llJZ7
CON'l'IlN'l'S
I'AGE
The history of the greenhouse-tomato industry a~ rclnt(~d to po1\inalion .. .
Previous work on pollination ........... ' ...... , ....... , ....... .
Nlltl'ition as n. factor in fruit setting of grecnholt&e tomatocs ............. '
Artificial pollination as u factor in fruit setting of greenhouse tomatoes .. .
Structure of the OOUHl.to flower as related to pollination ............... .
The process of fertilil',ation ...... , ............ , ....... , .......... .
g~~~i~~fn~~ g~~~~sc~E~~~~e;~f~~t~ 'fQ~ '~lii~'~lil;t; '~;pdrit~;;n't~:: ::::
VariQtics of tomatoes and methods of pollination ...
The emasculation method.
The watch~glass method. , .. , , ..
'fhe came['s·tlair·brl1sh rneLhod ...... " '"
{j~:/i~rll;t~!,l~~~h~~~~~I~~~~~t: ~~~~~~r~:: ..
Procedure ............ .
Planting JUrangomcnt. . . .
.
ResUNrr~~tC~r~~~w~ndts~i i~ili~l;~ti'o'li ~~; ir'lI'iti\~I~l~~~: ,: : .. "
...... :::::"" '"
Total set of fruit ...
Set (,of fruit on first three clusters .................................. .
Differences in flower morphology and pollen formation of tomato varieties,
as related to pollination and fntitfulncss .................. , .......... .
Effect of method of pollination on yield and distributioJl of crop ..
Effect of method of pollination on size of fruit. ' ..
Effect of ,method of pollilHl.tioll 011 shape of fruit ..
Effect of method of pollination on grade of fruit. . . . . .. . .. .
Effect of method of pollination on blossom-cnd-I'ot diseuse .. .
~~~~t ~~ ~~~:!~~ ~~ ~m~~~u~!~ ~~ ~~~~I~~rf~~lit~t,i~'~., :::.::.
SlIItlmary ....... .
RCCOllUl1Cndatiolls ..
Bibliogmphy ...
20
26
35
39
'f4
49
51
53
56
5~
5"
POUINI\'TION OF GRlmNf-IOUSE TOMI\TOES
n. W.
SCllNECI(
Aeeonlinf, to figmes published by Corbett (1927), there are nbottt six
thousand greenhouse establishments in the United States producillg
vegetables in all or part of their space. The total value o( vegetables
produced in these greenhouses is estimated to he $10,000,000 " year.
T... cttu(:c, CtlC11111bers, and tomatoes arc the three most important crops
raise(l, (lnd they represent at least $9,000,00D of this total value.
The tomato is becominlZ more importRl1t overy year, due larlZely to
the increased lmowledge of its importance ill the eliet. Tomato fruits
are very Jligh in vitamin content, and knowledge of this is tending to
greatly increase the deman(l for fresh tomatoes throughout the yenr.
The demund for fresh out-of-season tomatoes is being supplied by the
southern outdoor-grown crop and by northern greenhotlse-gl'Own tomatoes.
GrcCnhOtlSe-gl'own tomatoes arc becoming relatively 1110rc itnporlant 111
the northern markets.
It is generally known that the Ilppcamncc and the q'l,lity of
the northern-grown vine-ripened greenhouse totllato are far superior to
those o( the southem outdool'-grown fruit, whiell is picked grass-green
when large enough to ship, anel aJlowcc1 ~o ripen either in warm, unventilated ripening rooms or in transit. No attention is paid, in picking, to'
color or to degree of maturity, wllieh Sando (J920) hflS sllown to bedcpelldellt on the age and not on the size of the fl'llit. Most southem-grown
tomatoes arC shipped in refrigerator carS witho11t icc, the tcmperatllre
being regulated by means of ventilators, which are left open in thc Sonth,
but, as the cars travel 11ortll, arc closed, thus maintaining a confined
atmosphere with It deficiency of oxygen. Under these conditions the
fruits fLrc wrinkled, of abnormal color, and of poor taste, when they reuch
the nOl'thcl'l1 I1ladmts. Sal1clo (I~20) Eocmd that as the tomato m[ttLCres
on the plant thCl'C lH a 1l1n.d::ed increase in sugar and fl decrease ill starch.
Sancio's analyses of commercially picked southern tomatoes ripened
without ventilation show them to be high in acid cOl1tCllt, 138 pCI' cent
higher than vine-ripened fruit, and very low in slIgars, 2 L per cent lowe"
than vine-ripened [rl1il. These diffcrcl1e;cs in chemical cOlnpositioll arc
associated with, and account for, the great difference in flavor between
southern-groWll tomatoes and northern-grown greenilollsc fruits. While
the cost of producing tomatoes is tnlICh higher (or t.he Ilorthcl'll gl'eunhouse grower, still, because of the markedly superior quality and "ppe",'ancC. of the fruit, northern-grown greenhotlse tomatoes. cOlTltnanu tnllch
higher prices than, and call compete successfully with, those shippcd from
the South.
'l'I~~~~~~~:~ Jl;)~ ~~\~\i:''l~i~~ ~:~. ~tl;~;:~~ l~~~~I~: 1:'~li):r;~cwo~~~~~;~~~~?Cfll1~ll~O~~~)ii~;~ll~he Wf~t~r! oiThe ; ()~;
A
f'ltperhnenL
BULLETIN 470
THE IlIS'WHY OF 'fll.E GHgHNHOUSE-TOMATO INDUSTRY AS RgLATElI
'1'0 POLL1NATl()N
The modern g,rccnhouse is a comparatively recent development, antl
did not come into extensive lise for the forcing of vegetables until late
in the nineteenth century. Early in the development of the industry,
few tomatoes were grown in the fall, midwinter, and very early spring,
because greenhouse lettuce was marc profitable and therefore was grown
extensively at those times, Less fuel is required with lcttuce, since it
grows well at a lower tCl11perattn'e than do tomatoes, With the rapid
growth of the forcing illClustry, lettuce was grown by so many greenhouse
men in the fall and winter that there developed many apPQrent " gluts"
with consequent low p"iees for this crop, In addition, cluI"ing the past
few years the increased prodtlctioll of willter lettuce ;n the South, and
particularly in the Southwest, has tended to still further decrease the
profits to be obtained from grecnl10tlSc-grown lettuce,
In view of these conditions, greenhouse men in many large centers of
production are now growing tomatoes instead of lettuce as a fall crop
and also as a very carly spring crop, l'ractically all of these men, however, complain of low yields as compared with the yields obtained in late
spring, It has been thought that these low yields ilrc due lal'eely to lack
of proper pollination al1(\ conseqttent development of few and small-sized
fruits ,
Prclfioll5 work 011 pollination
Aside 11'0111 the comparatively recent work of Bouquet (1919), of the
Oregon Agricultural College, very little has been clone in all experimental
way to detennillc the effects of various methods of pollination of green-
house tomatoes
011
difforent factors, Stich as scI; of fruit, yjeld, earliness,
grade of fruit, and ,'eturns, P,'eviol1s work has been devoted largely
to cross-poUination of varieties, and the effects of various amounts of
pollen on size alld shape oE fmit, In most of the literature on greenhouse tomatoes, writers en1.phasizc the importance
or
SOO1.C
method of
artificial pollination, but practically no experimental data are given
showing the effects of different methods, Recommendations made either
are based upon observation, or are simply the opinions of the writcl',
In 1891, when tl1e vegetable-forcing industry wasoin its infancy Dailey
J
(.891) made the following statement:
In the short dull days of midwinter somA artifIcial aiel must. be given Lhe flowers
to enable them to set. The common pt'nctice is to tnp the plants. fihl1rpJy several times
dm'jnl{ i,lw middle of "he <.lay wiLh a padded sLick.
This JJl"acl..iclJ is perhaps beLLer
than nothing, . . . I am strongly of the opinion thaI, it will pay Lhe commercial
grower to transfer the pollen by hand during midwinter,
Bailey draw~ the following conclusions, among others, {rom his tomatopollination experiments: ([) "One-sidedl1es~ apVear~ lo result (ron1 a.
greater developmel1t of seeds upon the large side," (2)" This c1evelop-
ment of seeds is appal-ently due to the applicatiol1 of the pollen to that
side," (3)" An abundance of pollen appliecl over the entire stigmatic
surface, by increa.sing the number of seeds increases the size of the fruit."
(4) "The pollen, either directly or indirectly, probably stinllllatcs the
growth of the fruit beyond the mere innU€llee of the number of seeds,"
Por.CTNATION" <W CH.Hl~NHOUSE '_tO~fAT01~S
V'tr>i:ehcl" and Cmm~ (l!)()';) :11 '10 nolc(l Lh:tI: wllC'rc onl ~r a few PUH CH graiJls
were applied to the ~ U !~\I1a 111:111 Y of t.he htOSXOlllS did not l\latul'C fruit,
\\'(' 1\' slower ill ~tart.iug to clllar)!;c than
<Ind that those: whic11 did ~row
those from hlossoms which recei ved a I1beral :l1ll<Hwt of pOllCH.
Mum;on (,892), ,Nall" (,SIp , ''''7), Alwood (I8,)S), Corbett (1905,
19'3), Warren (,goo), }llctcher {1n<1 ('rel,;g ('9°7), BOllquet (r9'3, '9'5,
1919), fmel many others, in t1wiJ' writings on vegetnble forcing, recom~
mended and emphasized the jmportance of some 11lCailH of hand-pollination
of greenhouse tomatoes in winter. But none of these wTiters, with the
exception of Bouquet, nnd Fletcher and Gregg, give 111HCh I if any. experimental evidence.
Scvcl'at invc..stigators have noted l,hat the amollnt o[ pollcn which
reaches the stigma of the tomato blossom hus a m"rkcd effect on the size
and the shape of the resulting fruit, anu also on the rapidity with which
it develops and matures . Both Beach (,897) and BOt1qllet (1QIg).obsel'ved
n rapid enlargement of the lniniaturc fruits after fertilization whcn n large
anlO\lllt of po1(cn was used. \,\rhell only a small flTIlOttnt of pollen was
allowed to reach the s t.igllln, the resulting frllit was small ane! often lopsided or irregular in shape. These t1nc1c-1'si:wd tOl11n.tocs nre usually very
solid and meaty, und practically seedless. The effect of the amount of
pollen on size and shupe of fmit llas !Jcen illustrated also in the experimcnts of Baile), (1891), Mt1nson (1892), Alw00d (1895), Fletehernnd Gregg
(1907), uml Burker and Margolcs (r9[3)·
Experiments conducted by MlIllson (,892) show that insufficient pollen
produces small or onc-sided fruit. 'INhere he applied all excess of pollen
he obtainec1large symmetrical fruits. lIe fOIl11d also that the position of
the Oower in the cluster has no influence ill dcterl11illing this point. He
claims that lack of sufTicient pollen explains the calise for most of the
small and perhaps all of the ol1c-sici"d fruits se"n among greenhouse
tOI)1n.tOCS.
Munson (,898) suggests that pollen may hav~. a directing influence
which extends beyond the fer til i'l.nt.ion of the ovule. lIe states that it
(loes not sC0,.m improhn.hle that 110Hc.n fr(jnl n. vigo1'o\.\\; plunt 111ay lunke
an imprint of its cha.racter on the female organism , .vhich shall be different
from that of a less vigorolls lnale parent. N cvel'theless. in his work
with tomatoes there was no :in~tancc of :tny immediate cITct:t other than
alteration of fot'ln due to lnstlllicient pollen.
Wcliin1(toJ1 (,or2), in his stuol' of the effect DE crossing tulllflto varieties
to increase yjelds, fOl1nd -in all of his experiments covering a period of
three years tllflt tIle P I -generati,," plants produced higher yields than did
citl1cr parent, Imt lJ1at the 11'1- [lnd J1':d~·cncration plnnts feB of[ in yield.
lIe observed also thnt the irreglllal'ity or the surface of the tOlllato was
correlated with the n011 ~dcvelopll1cnt of ovules. lIe noted that premature
pollination gn.ve rt very poor setting uf fruit, corroborating the work
done by LTartley in 1<)0'.
Hartley (T902) sl'nwcd that tomato blossor\1s prematurely pollinated
before the sep"," and pdals were rcfiexe(l dic1 not set fruit. When pollinated before the stiv;rnn. \Vus l'c(:cptivc and again when -it wo.s receptive
3. good set wa.s Obtained, showing: that the pistil was not injured hy pl'Cmutlu'e pollination. When the pollen was loft on a watch crystal under
1
BULLBTIN 470
h'rCCJl house conditions for live clays and then applied to receptive pistils,
" vCt'y poor set resulted.
Hartley thus shows conclusively that pistils
must be receptive when pollinated ill order to set [ruit, and that pollen
must be fresh when applied to receptive pistils, I-[e fOl.11Hl that.. pistils
nrc receptive when sepals and petals are rcRcKed. J!clrtlcy did not test
blossoms to see whether they were receptive when fre~h po\\cn was appE_c('
to the stigma after the flower ha,l been open for several days and the
pctal~
were folded (lnwn over the stigma.
Massey aneL Rho,\", (l()oo) obtaineeL larger fruits and a better set of
fruits with an increased yic\cl rrom n. winter crop or tonlatoes, by pollinating
with a camel's-hail' brush as compared with doily j;-uring the blossoms.
'They stnte that most writers on the suhject of iOH1"ltO fo),cing advise
shaking the pollcn onto a spoon And then applying it to the pistil. They
did 1101. ww this mvthoLi, aml dHim tlrn.t they kllow of IlO <Jil0 who has
used it. Fletchcl· alld Gregg (rg07) did not lind the brllsh method as
satisfaetory as pollination by means oE a glass sline or a spoon. ';VaLts
(18Q2) also claims that the brush method is not so thorough.
Jenkins and Britton (1899) used
tl.
method of pollination in which the
corolla and the stamens of the nower were pulled away after the flowcr
had fully opened and the petals had begun to wither and clOf;C over the
sth~1l1a. As the stmllCI1S arc united to the corolla, the anthers arc brokcn
open in the process Qr removal; and if the pollen is Tipe and dry, it escapes
into the nir flI1e1 S01)1(_-> UStlHl1y 1'cAcht's the stigmatic sllrfa('e. of t.h(~ pistil
of the flower and fertili"es it.
This method caused as many fruits to set
as whc,oc the spoon method "·~lS used, but the spoon method of pollinating
took less time.
lJouquct (19f,~, 19l5, I9I1]) gives the results of extensive tl"ials made
ill cOl11mercial f:,'Tconhotlscs in Oregon, comparing yields of ha.nd-pollinated
plan(;~ wHh thos!.:! of jarred and untreateu plants. As a result of these
investigations, he recommends the emasculation method of pollination
for greenhouse tomatoes, in which. the corolla and the stamens are removed
"fter the corolla has fully expanded and again closed, the pollen heinl(
then appliell to the stigma by the fingers. He cites as the chief aclvantages
of the method: (I) pollination at a ti1l1e when the stigma is receptive;
(2) a sure, even, and ample application of po1\~n to the stigma; (3) prevention of duplication in poUinating; and (4) a smaller chance of overlooking blos-soms that have not been pollinated. His investigations
disclose the fact that, ill cOlnmercial greenhouses, large Humbers of frulls
"rc lost throllgh ul1fertili"cd blossoms. In the results repol·ter! in '9'9,
these were estirl1atcd to he as high as 60 to 70 per cent of the total numher
of blossoms. Bouqt.tet claims that hand pol1lnation reduced the nUl1Iber
of ttn(ntitftll blossoms froI11 66 per cent to 20 per cent of the total l1umbc'l'
of flowers produced. The average fruitfulness of plants typical of liftccII
crops of tomatoes which WC1'e hand-pollinated hy the cmasculation. method
was 72 per cent, while the average fruitfulness of untreated plants \Va~
only 36 per cent.
Results from both hand pollination anrl jarring of the vines showed
profitable net increascs over thosc with plants left undisturbed. Bouquet
concludes that it pays to hand-pollinate to the extent that the increased
returns
fill'
exceed il1 vnlue the Jabol' cost of the work and leave
it
margill
profit. He states that the cost of hand pollination for the entire
season may he, covered by increased yields obtained [rOln pollinated
o[
plant;i-: in the first two weeks of harvesting whOrl 11ig hc r prices prevail,
and that in some cases hand pollination by emasculation paid the entire
labor cost of production through increased y ields . He J:ccol11nlcnds
furtll(~r the neccs~ity of rc!:rularity and thoroughness of pollination as
eOllLiucive to high yickls, whereas illcxperit:nccd labor, haste, and irregu-
larity in doing the work, may not produce profitable net results.
Practically all writers and investigators on the subject of pollination
emphasize the ilnportancc al1cl inOuencc of sunshinc, high temperature,
n.ncl dry atmosphere on the formation, liberation, anclger111inat1.on of pollen.
Corbett (19J.) stntes that during dlU·Ie, cloudy weathe,· it sll1aller percentage of tomato blossoms will be fertiIi"ec] th'lI1 d'Hing bright weather.
Sandsten (I<)09) proved that cloudy weather retards the development
:wd germinaLioJ1 of tomllto pollen. He showed that the development of
tomato anthers is g,oeatly retarded by c loudy weat11er, Rnd that the anthers
do not open ,·eaclily ullder such conditions.
lIe found also that the rate
o{ growth of the pollen tube of the tomato is dcpcll.dent on. tcmpent.tul"c
:end on the amount of sunlight.
He found from repeated experiments
that tho gc\'millQ.tion was in<:rcnsed frOln 25 to 50 per cent in sunshine.
This increase, however, may be due to temperatl1re effect.
ICnowlton
(1922) stntes that, as. a rule, light has no direct effect un the gerrnination
of pollen.
It was "lso fnunei by Sandston ('909) that ihe production
and till.! InatllTing ur lumatu l)ollell arc adversely aILt:!ct"cU by ctoudy weather.
This may be indirectly ,hIe to the poorer "11(1 weaker growth of the plo.lIl
during cloudy weather.
Hutton and "VileDX (19l2) conductc(l a series of eXporlmcnts to study
the innuellcc of dillere"t factors on tomato-pollen germination. They
state that the literature 011 this subject is very meager. The J'CSttits of
their work mny be f'iL1Jl11l1arizccl as follow~:
T. The 0}1til~H._\n1 tempcrature for germlnation of tornato pollen i~ about
,14' C. (0,\° 1",).
2 . Tomato pollen germinates hettcl' in sunlight than in diffuse light.
')' Ivrnrkcll vnriati()n~ in vitality of tomato pullen al'C obsenTed at
1.1iffcrcnt tinw:-> of the )'L'<l1'. In general, higher porcentages of germination
\vcrc obtained as tho yenr advanced from January to Junc. The cause
of tl,is variation is probably cOllJPlc~. Light.. and lmrnidity jll tlw greenhOtlse af[cct the development of pollen within the "nthers, anc] perhaps
also influence the vilality of the poilen indirectly tlnough their influence
upon the entire plaut. Poor suit, weak light, and low temperatures arc
factors ,,~hicll inllucllcc not only the development. of tlowers, but peI'haps
to " gre[ltcr degree the (ievelopment of pollen.
4. Under winter conditions the best results were ohtained by collecting
pollen from freshly opened flowers, the anthen of whieh had not dehiseed.
Under natural conditions it would probably he best to use pollen from
spontaneol1sly tir.his('.e<l a_n thers.
5, Excessive htnnidity tends to prevent dehisccnec of i'lllthel's. Exces!-!.ivc dryness a11el heat tend to cause pollen to lo!-;c it!-; tYloisttll'e-l'esistant
propt'J'ties ;.)m1 to lJC n)ot'c cFlBily destroyed.
6. No differences wore found ill tho action of vurio\ls factors studied
nVJ.V~'I'IN "170
8
upon severnl varieties of the Stilne ~pecics. However, no statement can
be made that surh differences do not exist.
Goff (U}OJ), in a study of Lhc i!lfluence of \vcathcr upon 1..11c ullfsLing
of the anther" of cherry, opp[e, and 1'[\1111, fO\ltld that the anthers of these
plants uu not burst., 111 a. ulOist atmosphcTe. lIe nuted 'llsu that the viscid
secretion of the stigma which causes the pollen to adhere to it and to
germinate. remained iOllf_(Cr in a 1110ist atmosphere than in a dry one.
This indicates that a moist atmosphere retards the maturity of the pistils
as well as that of the anthers. Goff found also that a low temperatuTC
retards the bursting of the anthers. 'These experiments, although not conducted with tomato flowers, probably explain the l'casons for l'eCOl11menc1ations given to pollinate grecnhot1!)c tomatoes on dry, sunny days
when the temperature is high.
NUTnnloN ..\5 A FACTOR IN FHUi'r SIn''fING !W (;nf·;gNHOUSE
T()i\I,\'j"oES
Kralls and Kraybill (1<)J8), in their work on nutrition of the tomato,
have directed special attention to the importance of prnpcr nutrition as
a factor -ill the scttinR of tom::lto fruits. Tbcy f01..1nd that plants with n
very vigoroHs, highly ve_gctati"c growth were dccidcclly unfruitful, a large
percentage of the blossoms (ailing to set fruit. LH·.;-cwisc, plants which
made a weak nOIl-vegclativ(' gr()wth did not set much fruit.
'I'he authors
claim that vegetation and fruitfulness of the tomaLo pln.nt arc dependent
l1pon a condition of halancrd nutrition in the plant, which in turn is
largely dependent upon the relationship of carbohyd rate to nitrogen CO]1te.nt within the plant. 'J'h:is l"('lation~h\p is greatly :ICfcctcrl by the arno\_\nt
of available nitrogen nlld moisture in the soil, and also by the atnount of
sunlight and other factor'S 111\rotved ill ~)hQtoSytlthcsis. VCl'Y large amOtUlts
of nitrogen, or a deficiency of llitrogen in proportion. to c.:trbohydratc,
make for an unbalanced cundition of nutrition. During l)l'ight, sunshiny
weather, plants require antl can tltilize more avaibble nitrogen than during
periods of cloudy wcather.
V cg<'tnt1-ve growth and fruitfulness arc
dependent upon both sunlight and availahie nitl'ogcn, an ex.cess 01' 0.
deficiency of either one in proportion to the other causing \u1ft'uitfulness.
Growth depends as ltlL1ell lIpon the Jl1anufac{;ure of carbohydrates as upon
t.he presence of available nitrogen. Vcgdativo growth is greatly d.ecreased
if insufficient carbohydrate is manufactured., even though there be present
an abundance of aw\illl.hlc nitrogen and waLer. But if, tll1f1cl' the S8Jl1C
conditions of nitrogen and moisture, an ample axnount of ca.rbohydrate
is lnanu{actured, gro"wth will be active. \Vbcn vcgcLhtivc growth is
decreased by 1ack of suflieient llloislurc and niLrogc)n, an excess of carbohydrate is stored in the plant tiS5U~S.
Tl1Us ICralts and Kraybill lH.l.ve shawn that proper nutrition is just as
importallt a facLor in [rlLiL sel..tlng: CIS i:-; pn>pcr poHinntion. Before a plant
ca11 set an abundance of fruit, :it must be properly nourished.
AR1'lF{CIAL
['OJ.f.r~A'J'l() N
A.s A jo':\C'l'(1R TN
GRHgN!IOl1~B
!,'NlJ !'!' Sg'l'T{NG 0'<'
1'Ol\IA'l'01~S
The tomato is largely self-fertile, <lnd, in the lldd, poHinatioll of tomato
blossoms is accomplished hy the wind, \v11i('11 1i);crates the pollcn from
POU.INATION OF nR'JO~NIlOTJSl~ TOi\{A'l'On!'i
(J
r<!t'iliU!lillg tlJn :-;plfing of the hl(l~sml1S. Bumhlebees
;ITe fnlld o( t,{)!naLo fll)WI;~\, S , and p()s~ ill\ y :t{'('()\\tll fl)\' !iOI11C pollinnt.ion
in the (ie.ld. { f III1L'r :trtifici:d rt)Hdil')()ll ~ jn tl1c ~l'c('J1hollS(" t'lllTents of
u.ir ar e no(. ::;trt)llg l'lIul~gh to fa('ilitnt(~ iilll' ration of poilen, iuul hl.lmblcbccs
[lTC scldol1.l prc~c.Ilt.. Ilnlleyhl~l~s , whiC"h facilitale pollirmtion of greenhouse
CUCuf"!lbcr.s, do not work on tOlltato hlossoms, probab ly becfl:\1~c of the
pccl1lim: structure of the flowe!' Im(} the absence. of nce.tar. For these
reasons, most pl'()grc~sivc gz'ee-nhoH"c men feel tl1a.t in order to secure
sHcecssful rcsults, somc 111.Cnns of arl.ificial poUinntion mu~t be used.
Vet there arc many greC':nh()\1 Se~lOlnnto g)'owers \:" ho pay little attention
to pollination. The ~ornm()n pl':l.et.\cc foHowed consists ill jal'rinl~ the
5UppC.l'ts, the 'p Illnts, or the flownr clusters. 'rhis. metbod nppm'ently has
prov('(l fairly sat.isfactnl'Y in late spring, but in the short cloudy days
of fan, wintl"·, :111<1 ('ady s pring, sOl11e meaus of ~lcLt1ally obtaining and
applying thl~ pollen hn s heen thol1ght necessary in Ol'dCl' to get satisfactory 1'csnlt~, All c011flitinl1s nlHy be ideal foL' tho vigorous growth of
the pJnnt flD(i f(JJ' the d~v('1r.:)pl))('nt of many flOlvers, but if pollen docs
not C011le ill contnrt 'with the stigmatic' sl1rf:1('c of the p:istil the b105$i.oms fail to s~t fruit,
llu: clllLher
SHCS,
Wl'RUCTUH.E Ol-' THE. TOMATO
J.'L()\YJ~H
AS ImLA'}']O) '1'0 POLJ..lNATJON
1\ kn()wledge of the.! ::;trud,\.Il·c of tile t0rnnto {lowel' and the function
of the vn.t'i(Ju~ parts i!, essential to an ttndcl'f>tanclirtg or pollination a nd
fcrtiliv,ation. The !lowers arc horne in clllSlul'S 01 fJ'on1 foul' to finecn,
the: ntllubcl' to each clustc.l' dependiJlg lal'gdy upon the vRt'icty although some
variation j~ fOllmJ among di{Tcrcnt dustcrs llJl. a plallt. T'he flowel's on
a single cluster develop at diifercl1t times. so tbnt buds, flowers, and
tilll.all !rll-it~ llH\y all he found on a C:h.1StCt' at one tin'lc.
Exaruina.t..ioll of an individual tomato (lower ShO·W5 it to be composed
o( Hcvcra l dis('inet :-;trlH:t.ural l)artR (f1glLrc 1). The g-rcen, ::)tar-liic.c, outer
part of the nower, which dmiIls thc tOlliato when..:: it is joined to the stem,
iti called Lha coly.t: , and j(.; is composed usually of I1vc separate parts known
W"i so/mis, which arc joined at LhG bi:t5C. The coronct, a)ovc the ca1yx, is
[;OHlpo:-;c(l u[ yellvw 101)(:5, valletl j)clai:s, CUl'l'c!:ij)oJ1ding in lltullbcl- to the
ticpllll). The 1.1)111<11.,0 :is a jJL'rfccL-fluwon:'u lJli1nL, 1Joth male and female
~cx. organH being burlle in the ~al1lt: Huwer. The llollcl1. is n.lost freely
di~dm.l'g:cd Wh~ll til\.!. p~tah; axe wdl 1· .....,nexcd U\" fuBy e~palldccl. The
ye1low st..al llcns a re fuulId iUoiLle Hild above t.he l)(.:tais, and form a cone~
::;halJecl tube whit;h iHdost:!;) the gTca.tcr part OJ' [.t11 of the female sex organ,
lnlOwn a.s tile pi,rt-il. Tlte :-;t;:Ullon::i J.Jcar OIl the ilJner side , ncar the tip,
l.hc [lntlwl' !-;HCS in which the pollen is produced.. 'rJlC enla rged tip. Of
oater end , o[ l.l10 pislil is cflllf'd ilw stigma.. The snrface of the stigma
becomes nloi!":)t and sl.icky <lS tho petals nrc rully c:-::punrJc.d. If the po11en
grains reach tho stigmatic surface nt this tinw, they w11.1 ;1c1h~·c. to It and
mny germinate. 'J'Jle pedicel of the pistil below the stIgma lS called the
:ilyie und the enlargement at \..ho hm~c of the style is the ovary, which
ticvdlops -into thf! mntUl'e fru11, when the OVL11cs cOl1tainc.d ill the ovary
arc fertiliz.ed. The fCI'LiHz~d ovules dcvc.lop into mature seed.
'W hen t.he pollen grains arc ripe, as iud1ccltcd by the funy expanded
~
\ I}-c; \,\ l'jb
10
Germinating ,,pollen grain/ /
I
-__ Stamens
__ Ovary
corolla. they sift through the pores in Lhc anther SFlCS. If t.hey arc very
nbunclfUlt, some mAy reach the ~tigmatic surface of the pistil when Lhc
p1ants arc jarred. Tomato flowers usually hang in n downward position,
and if the pistil, when receptive, is longer than the ~tHmCng, po\lillntiOll
hy jarring has been thought t() be (Jinicult.
'fFIE PH:OCESS 01"
1?T~R1'lUZI\1'l ON
Pollen grains adhere readily when appliecl to t.he sti<'ky, rnoist, sligmatic
surface of the pistil, and if conditions flrc favorable they ger111111t..lte. Upun
gl:nni nating, each pollen grain
~cnds tl
slender, thread-like tube down the
style, lU1iting with an ovule contained in the ovary, 0'" cl11lJryol1ie fruit .
The fertilizing clement of the pollen grajn is carried dOWll the pollen tuhe
during its pmccss of clongrttioll; and when the pollen tube <lllc1 the ovule
unite. the C'ontCJ1t.s of each fuse, thus acco111plislling fertilization . The
ovule then begins its dcvclopme:nt into a. seed al1l1 the ovary into a fruit.
OBJ[':CT OF THE ('RESENT
BXPEIH~mN'1'
In ordcr to thl'OW some light on the relation of pollinati()l1 to frl1it
development of gl'ee.nh~t1se tomatoes, an extensive experiment wm;
plannecl and conducted during two consecutive years, having as its
object the determination of the effect of various methods of pollina.tioll
upon different factors. Ji'ive of the leadil1g varieties of greenhouse
tOllH\toes were used, Hnd the effect of different methods of pollination nil
IJ
thc following factors was studied: sct of fruit; total yield; carl iness; sir.e
of fruit; sbapc of huit; grndc of fr\lit; blossoJ1l-cnd rot; cost of producLion: net return.
(mOWING ANIJ )IANULING
I~X
'l'()~IATO
l'LA~'I'S
FOR
I'OLLlNl\TiOX
I'T':RT.\!1':N'I'S
The tomato-po\1ination experiments were c:onduGLcd in the late winter
n.ncl early ~pring Ot '920 n nd 1021. The seed for th(~ phlt1ts Wi1S sown
ill flats in Novcnlhcr. and the plant~ were set in tllC permanent hed in
the greenhoHse from 4-inch clay pots in .larnlary.
The greenhouses were of even-span, all-iran-frame construction, with
lrus:-;-stljJportcd roof.<;, th!ls ndll)jltin~ a maximllm aJJ10tlnl of ligJlt.
'The
hO\Jses ran cast and W('st. The plHnts \,>,crc pJaced 15 .inches .apart .in
3-foot rows r\lnning norl..h and south arross the hO\lSC, u.nd were pruned
to a ~illgle stem. They were nil headed back or topped nt the same time
and aL ihe sallle j1C'il~ht, this being when seven blosso111 cl\,1sters 11ad
dcv('loped on plant:-l of all varieties except Globe, 'which had six blossom
clust<.ws, Night tCtTI11cHlturcs o[ between 65 0 and '10 0 F'., and day tel'llpcraLlIrcs nf hctw{'cn 70° 1wd 80 0 1"" were maintained,
Y,\U1E'l'IE~)
til" 'J'(\I\J..."TOES
;~Nj)
ME'l'lJOJ)S OF
POf,UNJ\TION
Jn
the, ()20 experiment, IOllr o[ the lIlost popular A tllcrtcan varieties
of tom,!lo('s were IIser}: Bonny Best, John Bael", G·lobc, .:l1lc1 Beauty,
For the IC)21 experiment, Comet, which is one of the hc!-'t..-kl1DWll and
IlIOSt. wi\lcly grown varieties of the English lype, was ~uhsti.tutcd for
Be1-ltlty; the n\..her thn;e varieties grown in 1()20 were LtsC'(1 also in 192f.
The foll{lwin}~ tl'catrncnLS were used in the 1920 expuri11l(!nt: crnaSCtlInt.i()n; watch glass; jarring the plants; \I11l1isturhc:cl plants rdcrl'rd t.o
a~ ('l\ccl{H.
Thl' same treatments, with the addi.tion of that with the
cumel's hair br1lsh, were Llsed itt H):2 r.
In these ('x!y(~rjI1WI}t~, the pollcll Iised j'l 1..110 {'nl<.lsculatitll1 allCj 1va.tchglass 1llelh(J(ls was collected from end plants And frolll those in olltBidc
rows not. included 111 the experiment and on which 110 l'G{.',onls were kept,
ThiH Was done in or<1er to eliminate any other factor, ~\wh a$ jarring,
'..vhich mi~hl; aid in pollination of blossoms under experiment.
'{he
ellu..tSC/I{(l(,·O/1
lIl£'iilod
pollinating jJ\ant~ by el1la~c111atil)1l, the pollen is l;ullcetcil On the
thlllllh l1a~1 or on the t.ips of the tin.;\.. and second lingers (If thl! l,·(t hand,
from J't)\vc'rs with pt'tab wpH re~\'x.cr!. OnJy l1mvers \Vhi(~h have been
fully 01)('11 :tnd have closed t.heir petals arc pollinated, aftet" the vctt'ils
J11
,lIld st:lIl1ens IlHvc been removed.
As Lhe st,,jfJlC!lS are attached to
th(~
fnl'nJJ;!, hoth may )(' t':lsily rr!11o\'cr) iJl nne f)pcratio!} 1)), gras])ing the tip
of 1,11(' wilted ('o1'o\1n wil.h the tlllttllh and t.he first Dr !'-;c('onct rlll,L!'Cr of the
jr·ft hand, holding t;he flowl'r ba(,k of the r(t\yx: with the right. hand, 'Then
pnlkll i$; applied to the st,iglll:1 hy lightl~1 tottching the sLigrn.attc surface
with •..'iLh('1' Llw flngl'l' ur tht; lhutllh nail clive red with the pol\e1l. The
LlHl111h :I\ltl t.he fir;.;\. flng:er of the right ilalld are used to stt';lIl~1 thl~ bJos;,,;olll
during the operation. vVit.h this method one must be carc{ld, ill l'ClHuvillg-
BULLETIN
12
470
the co roll" ano the s(nInens, to pullstraiglIt away [rom the (lower, <Jt1wrwise the pistil may be brokeIl at the base of the style. Thel'o is also
danger of hreaking the pist.il when the linger CQvcfC'c1 with pollen is brought
into contact with the stigma, bCCHl1Se the natural support furnished the
pistil by the stamens and the corolla has been removed (figure 2, c).
The watch-glass method
III the watch-glass method of pollination, a quantity of pollen is colledce!
on <l watch glass or a glass slide, from flowers which lJave expanded petals.
The watch glass is tJlen held ill the left hand, being placed jnst beneath
the flower w'ith well~reJlcx.ed Jx'tals (figure 2, a), anel with the 1'ight hand
the stigma of the flower is gen.tly brought into contact with the po11en.
The pollen might be collected on the thumb nai l 01' on the tips of the
lingers of the left banel, as explained undeI' the emasculation Incthod, but
the watch glass is probably more desirable. If pollen h applied prematurely, it may lose its vitality bcCore the sLigllla. becomes receptive,
ane! fail to germinate. However, the work of nartley (r902) indicates
that premature pollination clocs not injure the pistil, so that if the pistil is
again pollinated, when recepti\"c, wiLh fresh pollcn it will probably he
fertlli.iwcl and fruit wiH develop. Jl11 important <Jclvantage of the watchglnss method under comt11crcinl c()nditions is tbat the supply of pollcn on
the glass constantly increases as t.hc work progrcssc'.:i, because the pollen
may be procured from blossoms to be pollinatcu by tapping them before
pollinating.
The cQmcl's-/zair-brlfsh IILCtllOd
Aside from jarring the plants, tllO cnmcl's-lltdr-brush method has
received more consideration by COllHllel'cial growers than any other method,
because it is simple an(l quick. The brush is twirled with the Hngcrs on
any blossoms t.hat apPQar to be in a receptive condition. Sttpposedly
the supply of pollell 011 the brush is autoll1atical1y increased as the worker
PI'OCCCUS, but it js f.ather difJJrult I.,() tell when t.h e supply is rUll11ing low
on Ute bnlsh or whether polien i~ l'l.'ally being li\)lTalcd,
j(urillg the phLHts or the flower dusters
Jarring the plants is the met.11oc1 which pracLicaUy aU COlllrncrcial greenhouse men usc, cllief-ly becausc it 1S the simplc).;t, easiest, and quickest
method. Thf' plants or dt1sters mny hf' jarred ill various w~r:vs, hllt the
melhod employed ill Lhese experiments W[iS to grasp the rn.1in stem of
each individual plant and sh<-1ke it shnrply. Janing WrlS ;11ways done
towanl noon, preferably on s11nny dtlys when the temlWl'atlirc was high
and the aimosp1wrc elry.
U1/(iI'stllrbcd,
OJ'
cltec!,', r/ttl/ts
Plants nAcrrcd l\) .I~ "checks" 1Il Liltst..' cx.pclinl(\lli~ rcceived no
nrtificin! p():[1nalion. They wC'n (lis(uti_)t..\d as Itt.tlc clS possllllc, but. in
pruning [tl1d taking c[Lre of the plant.s, wJ(1 ill pollinating flowers of Of,her
plants, slight disi.urbance of the check plants pruhably took place.
POL1.INA'!'lON OJ! GrnmNlIOUSE TOMA'l'OI~S
I~Ir.l7IH;:~ .
TOMATO lrRUlT CLUSTglt SHOWING VA1UOUS ST!\..OgS 011 lrl.OWRll AND FRUIT
DJWJH~OP!;f1mT
b: \~i~I~~r~\:,: \~::I:~~~:~! i\!\I~I(~~~ ~I!,;:~~J~~~~{~I\~~~~O~\~~~(lt:~~ (\vj ~:~;~~~l~~~~ 1:~\i~l(,:);I'~~~\~~e:~ :~;~'4f 0\' p,)l Ii l1ul iQn
11.1' tlwcflll(';c'u/lttiul! tIIc(h(/(l
(,
rea,h'
Ilnllillnlioll
,I, j'rnit (levelol,iu)(
jl-Dllinall.lIJ
the
!.howh'i! pilltil htlachtd hilt
\lIll.a!ll rr.movcd
1~lIlafi{:l1lalc\1 !lol\'\lr
[lOll!
j:
(01'
IhJ\\'I~r
h}'
CJl\a~\!ulnlion J1\1;tlhJI!,
t~~~ltl~~\'f~~f~6~i~;?~dll~~~~~ ~~~~l~l~e:~ f~~i~hc watch'ul(\~s (ncillo.!, Illlowiu lt petnlll uUtlC}lcd
BUl,LETiN 410
PToce(lure
The h311c1-poHinatec1 plants were gone over thirty-seven times each
season, and those which were jarred seventy-four times. The first pollination was given on February 4- in 1920 and on February 2 I in lC)2 I, and
the last on 1,,'lay 5 111 ] 920 nnd on rvlay 16 in 1921 - a periocl of lwelve
to thirteen weeks in each seaSOll, It was the aim to jar plants every day,
and to hand-pollinate eVQl'Y other day, but on dark, cloudy days no
pollination was done. It was found that blosso111s develop much more
1';i.pid\y in sunshiny wea.ther t.han in cloudy weather. 'rhe plant!!. were
never left longer than three days without attention to pollinat.ion,
Pl,ANTING
AI{RANGE)ll~N'l'
The plants fol' the 11)2 I experiment \Verc arranged for different IlH~thl)(b
of pollination a.s shown in figure:., Each marl...: represent.s one plant,
The rows at each cnd of the house, the LWO rows in the middle o[ the
house adjoining the ventilator wheels, and the plants at the ends of the
rows on each side of the house, were not included in the ex.perimont.
'They W(',1'e di.scarded in order that plants on which records were tal{cn
would be exposed to uni(Ol'll1 growing conditions of soil, moisture, temperat.ure, and sunlight; also to provide blossoms from which to collect pollen
w;;eci ;n h;;lnd pollinating. The ph-1nts in the two I'{)WR adjoining the
ventilator wheels WCre not included becausc these plants were more or less
disturbed in ventilating, A sin1itar planting arrangement was used for
the (920 experiment, This anangcll1cnt left twelve ,'ows fief'OSS the house
in the experiment euch rear, There were three similar groups of plants,
four rows in each group, with one row of each variety in each group. III
f()2 r cad1 group or set \V~IS divided into five parts, and pollinated [IS
follows: emasculation, wntch-glass, brw-;h l jarring, Rnd check, Each set
of four rows, therefore, contained n row of each variety, and each set
was divjc1cd into five divisions of sixteen plants each, f0111' plants of each
variety 1,1)\1$ being treat.ed with each method of pollination in each row.
There were 352 plants in the hotlse, 24_0 being in the experiment, making
(1O plants of each variety in the experiment, and a total of 12 plants of
each variety 'Under each method of pollination, T]'1s arrangement pro"irlcd for n uniform test in tbllt eoeh variety with each method of pollination
was testcc1111 different parts of the house.
In 1920 oach group or set was. divided into [ou\' parts and pollinat.ed
as follows: emasculation, watch-glafis jarring, and check. The brush
method WWi ]lot inclu(led in the 1(}20 experimcnt. Each ):)et in !()20,
thcrofo1'c, contained a row of cach variety, and each set was dividcd into
fOltl' divisions of sixteen plants each, {our plants of each variety thus
heing treated with each method of pollination in cach row, There were
252 plants in the hmlse, IC)2 bring :in the ,experiment, making 48 plants
of each variety in the experiment, and a total of 12 plants of Dach variety
under each method of pollination, A few plants in the ex.periment each
yenr, as already indicatcd, were not c()nsidcrcd in taking I'ccorc1~ h(,CH\t~(,
of their relativel)' poor growth,
l
[5
POLLI NATION 010' GRngNlIOUSB 'TO ,V t,\TOE :-;
John
,xx
x
nitel',
C heck
Jolln Hner
x
Globe.
X
J)onny BC!'it.
x
Com el. ,
x
"
()
(]
n 0 no
x
0
0
x
u
() U
Bonny .Best.
Wntch-
Jarring
Bru sh
0
"
"
Q
0
"" "
00
John Hal' 1' ,
""
(I
x x x x
'"£
x x x :<
0"
()
""
()
"
<)
o
"
(J () (]
r)
()
[)
I)
0 0 0 ()
Rmascllialion
Vhltch.
glnss
0
000
Check
"o "
I)
(.1
0
0
OQG
II
/I
H () 0
()
()
<10
(1
()
O()
X
J~l1las.
"
0
on
""
""
0000
x
x
Jarring
0 () 0 ()
x
00
x
(l
(/
x x x x
x x x x
Ventilator 0
0 whcel~
x x x x x x x x x x xx
x '1:1
x x x x
"s-
x x x x
x x x x
x x x x
Comet. ..
x x x x
cu!ation
0 0 0 ()
Clollc' ,
nQllny nest, .
Path
x x x x
-----
0 ,, 0 0
0" 0 "
" 0" " 0 " 0 0
a
00"
0
" - - - - - ---- -----
1,rl1!ih
(,lob!.! ..
x x x x
gla s ~
()
---
-
000010000100(")0
aoOO
OOQ()
nono
0000
0000
oono
Bn1 s h
c~~{~\~t~~l
0000
x
---- -------------Ch('ck
John Hac!".
x
GlnlJe. ..
x
Bonny llt':{t..
0
0 0 0
0
JaninK
" ""
0
""
"" " """
Q
0
')
0
"" " "" "
0
x
X
,, ,xxx
x x x x
n
"
0
0
"""
" " ""
""""
..
C')lnd. . . .
('{}l1wL.
\~f~~!l-
0
x x x x
x
0
"0
,xx
Path
"'i
S --
I
--- N
I
('j
The ligures given in the following pages, in discussing the results of the
experiments, are the averages of the two experiments find are based 011 the
total number of plants of encll val'iety for dii)'crent methods of pollination
ns shown in table 1.
TABLE I.
OF ])f.AN1·S 0[0" BACH VAIUETV WI 'I'II EACH
TOTAL NUMll lm
r..ll(THOn OF
rOI"Lr~ATION
.McLllOd of polUnatiOJl
V(wicly
I
IJ
--ro-[-;,-"
B,'ush
(19lI
only)
' 1g
.Emasculation
\VnLcll-glass
John Bact'.
[9
20
Globe" " " ,
Bonny Best ....... .
Comet (192J only) .. .
Bea.uty ([920 only).
23
20
20
20
10
19
8
12
JO
12
I~?
[~
82
82
41
.
Totals of all variel.it..'s
Check
plants
(ll'flI
~""
2;\
22
[I
---- -- --- -1--- \
12
[2
Sz
92
_
RESUL'L'S OF r.:XPERD.J.IZN'l'S
E,O'ecl oj meltrort of polUIwtion on fruitJulness
Tolal sel oj fruit
The average percentage of flowers that set fruitt, fOl' all varieties te;:;ted
with different mcthous oC polHnaLioil, is shown ill talJl~ 2 l.o be as follows:
emasculation 79 per cent, watch-glass 79 per cent, brush '12 fler cent,
jarring 58 per cent. check plants ,p per cent. Almost twice as many
flowers !)ct fruit on plants pollinated by the emasculaLion or by the 'w alchTABLE
Elo'FECr
2.
OF MF.TlIOil
OF
POLI.INATION ON
SIt'r
UI~ FRUIT
(T()tal for two years, 1920 and 192 1, (:xccpl. where indicatl'd)
'l"oln.l:!
nnd
J ohn
Drier
Globe
Honl1}'
Comct
Benulr
Bcst.
(J9~J
(Jf):}O
011[}')
only}
~~~
~~~
j~:~
- - - -met!)'Od
- - - - 1 - - - - - - -- - - - - E.mr!.~\I\nWl)n
~~~~~~ ~~ r;~i::~~·.·. '.'
P()r cent of frnitfiet..........
Pel:" cent inercnllC over jllrtiul: . .
~6~
18.8"
.03
J~
Zi~
81.1.1
27 .8(>
79.1ij
IU . 65
82.33
31.97
tWCnl!lcs
oEnn
vnrietic:l
3, 192
:Z ,5 1 J
11i7.j
;jl>·su
10·.19
4'1 . 3J
-"P.::_e'"':,:.,n::.:t_c;in::.:,,-,",,,us,-',-O'..:.":...':._h.c_
"",k;':_"C'I ___-,0,-",,,".:..'_1_---'6J:.:''-' _:~ ~~_
·Wntch·,:\ll"Sstl\ct hod
Number of blo~soms ....
N\llllher of fruits set .•
Per cent. of fn'it eet. ........ .
~et
..... .
l'crcent.offmitset ......... .
Per cent increase over jarring in
IO:i!ll . . . . . . . . . . . . . . . . . . . . . .
.,9
3"
69.93
~
Per cent increase over check in
1931.
.SJ
5l.69
34 6
'90
83.81
43'
291
6'.:16
1,3M)
Numuerut(ruit$50t ..... .
Per CClll of fruit set. ....... .
Per cent of fmit sct in I9ll.
Per cellt illc:reaM':
on~r
dlcck ...
Gh~;'~II~n~~1lJ!uswllls .....
N' lmhe.r of fruilsset.
Per cent of frl\itset. .. . ..... .
Fer veIJt at fruitll"et in JfJ2{ .•.
7.')6
.~f).
71
68.2
42.2951.03
47.0J
J , 20/)
49'
,\0.61
4 6 .1
747
474
63.45
10.7
.
28.0il
--.,
4S1
49 . 56
S8.9
-
5~1.79
IS·f·SS
~-~
90.(,
3,136
2,480
79.08
31.17
91.,)7
--- - - r
568
,80.~
1,3°6
·10·1
71.12
'/'J.3S
19.99
38.07
7 .~6
18.54
--------~
Jarring metllOu
Number o[ blossoms ..
7j·05
:10. 0
39.71
.-~
NlulIbeJ" of inlits
,1°.1
H'J.lh
Por cent incrense over jarrinl-( ..
Per cent increase over check ...
llmsh method (rQ2I only)
N'unher of blossoms,.
55:~
419
341
(i.R7
~.------
1'~2~
.~4. "
6:.1.8
4 1 .08
l,rlll
467
38 .50
44. 6
4"
:1:16
60.0
('9.0
l6.,pr
609
36,
59.21
:;9.~1
82,\
4,28.1
39.j
lI,40 0
41.81
. ";8:;5
yy6
'1.(11
26.8t
.~7 .65
67.7
39.59
'h9·11
2.043
<11.33
5 ll ·'1
POLL1NATION
1
ort GRm~NlIOUSU
TOMA'l'OES
17
2
FrfjUlm I~, TWO <":LU~i'rrmS OF "WE co~mT Vt\lHW1'Y POLLINA'I'ED IlY (I) '1'111,: E~rASCU·
/.1\1' ION ;H1~'r'JlO!) ,\NJ) (2) 'J'lII~ Wt\'l'C/f~Gl,i\SS MJ·:rm}J), snOWING A JIlZi\VY SET OF !lIWIT
glass method, as
011 check plants, Hnd oVOr a tbil'd Jllore than 011 jnrred
plants (figure 4) . The percentage increase in set with the brush (com-
paring I9~n results) and the jarred plfll1t.'i over the check plants is in
each casC approximately 40 per ccnt (figure 5). The hrl1sh 1l1ctl1od
(l<)? I results) produced only 7 pCI' cellt increase in se~ ovel' the jarring;
method, Thc};c recanls wCl'e tHken hom moro than three thousand
blossoms with each mctho([ excepL the hrush IllcLiLud, 1n whidl case over
eighteen hundred blossoms were con$idered. Separate counts were made
of the total 11\.11111>01' of hlossoms, antl the number that set fruits On all
the clusters on plnnts of different varieties with dilYcrcnt methods of
pollination (fig\ll'c 0).
The J'csults indicate J.;Oll1e variatlul1 with diJIcrcJJt varieties, although the
differences due to pollination 111Cihods aro fllidy l'()I1Si~tcnt. T'he Globe
aud Comet \~ari()tics .set fruit r('ndily, ,showing it higher percentage of sets
than oth(.'t' varieLies wiLh all pol\inaLiol1 lllcL\Jods anti pnrLic.:ularly with
jarred :lIHT ehcck plant;s. The C[l::i(' with which these two varieties set
fruit prohahly. ;ll'(':Oltllt:-: for Lheir being f~rl)Wll i1Iure cx.L(.'llsivcly than
other varicLi('~ ill gn.:unhousm; during: fuJ[ and win Lei', wilen it SCCIl1~ almo:-;t
il11possible Ln gpt a sntlsfnctol'Y sct of fruit with other cOlnmerch,dly important varieties. The Globe anu Comet va rietics produce fTuits which are
natul'ally few-seeded/ and this may explnin, in port at least, why they
18
BULLETIN 470
rlR5T THREE: CLUSi£RS
PCR CI!:/'IT
/59.
15/.S
£171'18.
WG'.
tJR.
JAR.
en,.".
w. G.
!3R.
JAR.
--
//2..
42.
LI'ITIRE 'PL ANT
81
91.
38.
40
FrGUIUI.s. PlmcENTAGU: mCRE:\SI~ IN SET or. fRUit DUE TO D[I1·
FERENT l'OLLIN"'TJON METHODS. OVER TilE SET ON UNlJIS'I'UIUlED,
on cnECK, i'LANTS
(El1H's.=clnm;~\11I1ti'.n;
,V.G.""watch-glnss ; Br.:::.hlltsh; J ar.=jArrimr)
}r+
rt
~2{ }
0
3
r
t
H
FIGURe 6.
I
L
sli.'f 01' FfWIT AS SllOW!'l Il'{ TVJ>[CAI. CLU!-iTEHS 01' DWJl'F.RJ~NT VAR1E'rms
AF'l'~[{_ f{EM:OVA(. OF MATuni?, FRUITS
Thick 6toJllS tl.lld large senra indicnte thr.t lnrlJC fruitll have been dcvclopcd and harvested.
Rtoms with 110 o.nh.rHon~6nt nl tho. end illrlicate that tlle blo ~!lO"\S fnUed to mIt fruit
SlcndC:r
!: 1~:I~:1f:s:l: Ah:r~I~,~~I~~~:~1l~6r~rp~~I~~~itJ6~;·1~~j~~.I;i~~' I;C{ 1~;:.1~~~~; °N~~t'I~~. ~)C[)!)!;I?~~\\l
J. Glo~:
4 . Comet:
G. wnlch_glullll. 81:1 J)(lr C(ln.t~Qt; II, brllnh, 50 pl.lr centj [, dlock, 0 IHlf cunt
Jt wntch-[liass, 75 l)cf cenlsctj K, brush. 44 per cent: L, che\:k. 0 per cent
POLLINA'rt()N OV GRH'RNT-TOUSH
'[ 'Oi\rATOI~~
19
are so easy to pollinate. A. few-seeded variety will natura lly ,·eqllire
fewer polien gra ms to ferltllze the ovules tl nd to exert the necessary
~rowth stimulus On the l)el'icarp to CHuse normnl full development of the
fruit, t)U111 will a many-seeded variety. The G lohc variety sets f ruit as
wcll w Ith 1..he \)1't1 ~h nlctho(l as with the CIIIClsC' lllaLioJ1 and watch-gla:;:-;
methods. This is not; the situation with other va rieties vviLh which -this
method 1S used. '],l1 e Beauty va riety makes a POOl'('J- set lhan W1 V other
variety with all methods, especi all y; 011 c:hcck plnnts, in wbich -the sd
on the (;10})e ;.uld Comet varieties is about douhle that a ll .Beaut y. By
Lhe l'1llasculat.I()1I Hnd watch-glass treatments th o Beauty nnc1 Bonny
Best varieties g ive the largest incrcrtscs in set of fruit over jarred Hnd
eh cck pla nts of any varieties tested, showing that t.hese varieties require
more careful attention to pollination than do oth er varieLies in order to
/-iccurc :l gond sot of fnlit. The C'oll1et variety gives the lcnst increase
in set over jurre~l ami check plants when polli.nated by the watch-glass
or the cmasr uintlon m ethod, showil1!!: that this va.riet y requires less care'
with refcrenc;e to pol1inatiol1 than do other varieti('s so far :IS the set of
fruit is conce rn ed .
.'jet oj }mil 011 first 'hree elusters
It waS thought important to obtain separate data On the "et of fruil
(or the first three chlstcrs, because ma ny greenhouse men complain about
getting n. poor set 011 th.e lower clusters in late winter au(l carly !->pring
with the jarring mctllO<1, whic:h produce..;; a fairly good set of fruit nn
the higher duslers. It waS thought thftt possibly other methods of
pollination might give better settings OIl the lower clusters.
The average pCI"celltnge of lrl1itfi.,lness for the first three cluster" with
difte rellt methods of pollination, for nil va rieties, WAS a.s follows: C111flBCltlation 6:2 pCI' cent, wateh-glass 60 pel' cent, hrush 5t per cent, jarring
34 pe]· cent, cheek plants 2,> per cent. With each methocl the set of iruiL
W.flS COJ1.'1jdcrAbJy Jess thLIJ} LJJNt: wjLb t.JIC SFLl.JJe IneL}lOd 011 the entire pJant,
showing that a. smalle r set of fruit can be expected in winter and early
sprin g on the lower clusters thnn on the higher ones. The increase in set
of frllrt ·with the emasculatlon 811d watch~glass methods OVC1~ tl1£lt with
the other methods if.; much 1110re marked 011 the first few clusters than when
all the olusters are considered (figltrc 5). This emphnsl7.es the gl'cater
importance o£ carefully hanel-pollinating the blossoms on tl1e lower clusters
nf the plant in late winter or carly spring.
Pollination of the first three cluste rs by e mascnlution produced an
incrcase in sci; of fruit of 159 per cent over check plants (figure 5) and of
84 per cent over plnnt!-> pollinated by jarring. The wntch-gla5~ method
produced similar in("rca"cs of 151.5 per cent and 77 . .1 per cent over ehcck
Hnd jarred plants, respectively. The brush 111cthod produced increa~e s
uf 11 2 pCI' ecnt and 49.5 per cent over check plants [lnd jarred plants,
respectively. J"rring thc plants produced an increased set of 42 per eenL
over check pJants.
As when all the blossoms
the plant were considered, the Glohe and
Comet varlctics were round to be easy to pollinate, to respond morc
rCfLllily to hand m ethods o[ pollination thnll other varieties, n,nd, furthermore, to sul1'er less, so far as set of fruit is coneerned, from lack of attentioll
or

Download Report