26

In t..is study, it is important to dettect the time of occurrence of
chinge in phise of activity of Som and to derive pro,eny from a ce.l in
wnich this occurred. for tnis reson, the majority of tests of Spm
benavior were conducted with ev rs of slants rether than with .-ollen
because cell linenges are m e evident in them. #-ch slant had a lisited
number of fert le esrs th: t co ld be used for test purnoses and a decision
had to be mace in tne te t of any one -lant regarding the tpeof teste
plant thet shou..d be used as pollen »zrent in the sross to eich eur of the
plants wnose som was desired to ve examined. If the 2 ve..ance of the
Stalk ind Lle-ves of the plent i: dicsted th.t it had st rted its development
with an active spm, a cross was usually made with it us. nz o-len of a plan
gaaving no opm that vas hovuiszygous for as and bt, and either x or wx,
desenaing on the co stitution of the evr-besring plant. If the 2ope rance
of tne plant indicated thet opm was in its i-ctive ph se in most p.rts
of the slant, then a cross using oollen of a slent howozvyszous for Bay bt,
and ec: rying an active som was iiudic».tcd for 2t Beast one of the fertile
eirs or the lant, and for rernsons thit vill be made evi‘ent shortly.
when possible, another eur of this sme plant was used in a cross with a

“

plant homozysous for An and bt and having no spm. srs of some plants

asving either an initi¢dsily active Spm or an initiabhy insuctive opm in them
27

. ; . ; n-1
were used in crosses with pslents that carried a class I stute of an

and bt, but in which no Spm was vresent, in order to examine the resnsonse o
the chosen class I st:te of Spm thit was contributed by the e2r-benuring

ce ; n-1L +
parent. Since many of the tested vlants were a,” (cl2ss II) Bt/a, bt

RS

. ; , a oe a . . |

in constitution, the direct respou:se of tne clss I stuie to Som in the fema
A

parent corid be observed among the bt class of kernels on the resulting

ear, as the large majority of them receive a, and bt fron the e-r-be:ring

2
parent.

In the summer of 1957, the only plants howussygous for ag , bt, and wx
and having an active som in them were plants 7308D-1 and v-2. the orisin
of tnese two plants from the Bos bt, wx class of kernels on the self-
pollin:.ted e.r of tiller-l of olent 71098-e was described exrlier. both

tessel of
plants produced three tillers/ Follen collected from the,main stalk
and from thot of exch tiller wis used in maxing cross:s to a large number
of plants n ving either a class I or mxgkss the class Il st-ve of ait
and cerr,ing either no Spm or one or wore som elements in the active or
the in:cetive phase in different o:rts of the plant. fine pnenotzs ces of
kernels on the enrs these crosses produced indicated that olunts 7308D-1

and D-e each had one Spm an» thit in the pollen derived from all parts of

e ch slant, the spm was in its active phase in ne rly ail of the pollen
28
grains that carried it. Prom the one. otypes of the k rnels on sone of
these ears, it was first lezrned that it wis possible to distinguish
whether or not a uniformly pignented, eir-besriny plent had no som in it
or had an Spm thst was in its insctive phase. Tais is because Som in its
inactive vhase, although un»ble #&h@one to effect suppression of gene action

m-1

with the class I and celss II sixtes of a , and to irduce mut-:ition with

\D

i}

the class I states, behzves as if it were in its active pshase wnen it is in
the seme nucleus witn an spm that is in its rctive pnase. dowever, tnis
association does not induce an alterstion iv the phuse of activity of eithe
opm. when the active and inictive Spm elements are se re 2¢ed into
different nuclei by the meiotic process, theactive »pm eleient conti> ues

in its active phase whereis the previously inactive som eleent reis cars
in its in=ctive phase. this t ve of test is-so effective th»t it hrs been
used extensively i: succeeding years to determine whether or not an
inzetive spm is present in a purt of a plant thet exhibits no evitience

of the presence of Som by the phenot pve of its stalk, Lon¥S or tassel.

“se of tais test h.s made it ‘ossible to inset the "-" symbol in many of -

¥

the vlaces where it appears in swemery tevles 2, 3 and 4 * Illustrotions

may now be given of tne types of test that were co duct. a with e ch :lent

in a culture and the effectiveness suf erch test in det ruining tite oresence
Po
Ke.

or absence of opm in a olant and its paase of activity in the v rious
tested ports of a plunt, should spm be sresent in it. for tis ourpo e,
tests of the sro:eny derived from the ear of the main s.alk of slant
7TLOGB-1 (see exbles 1 and 2) and from the evr of the main svalk of slent

71090-4 (see t-bles 1 and 4) may be descrited first.

sernels were selected from the first sr o* the main st lk of >lant

71098-1, shich was a m1 (class II) Btfa, bt, «x +/wx Spm in co:stitution,

2
and the plants grown from them in the summer of 1957 received culture
number 7456. The vlants in «a, B, and @ of this culture were derived
from uniforuly oisgmented kernels, teose in « and B fro: tne Bt cl-ss and
taose in w from the bt cioss. vlants derived from Bt kernels exnibitmng

~

the 'diffuse-mottled" pohenot oe were grown uncer v of cubture
-$ - 4

7456, and those derived from Bt kernels that wexexemkuxizesxbut shoved

small syots or syecks of pi.ment in a non-pigmented backsround were

grown under D of culture 7456. The tyres of test cross co ducted with
jase 22 of tae plants in this culture 2 e entered in txrble 5. In t- ble 2a,

under Yesr 1957, is recorded the behavior of »vpm in the cells Giving rise

to tne tested ears in eich of the Spm carrying »vlints in culture 7456.

a | .

For esch ear, the given symbol referring to! activity ph e of “pm was

based upon the she-otypes of kernels appearing on the ears derived from

the crosses entered in table 5.

In table 6 are given the tyses of test cross that we:e co. ducted with -

plants in culture 7455 that were derived *rom seleetcd kernels on the

( nec yur? v}

first ear of the main stalk of plant TLOQU—4 This plent was Wx/wx and
t
cavried 1 Spm thet was not linked fo eith:r of these alleles. the

plants in a, B, and D of culture 7455 were ceriveda fron Bike nels tast

y

exilbited the ‘di®fuse-mottled" phenot, pe. Those in ¥ of culture 7455

were derived from Bt kernels that had s:ots or syecks of color in a
UNWIN

colorles: back, round. as toble 4 indice: tes, e ch of the 18 tested
A

+

a
bh
5
od
ct
n

plants in ec: lture 7455 had an Som eleuent in it, end in wa
inactive pha e in the cells that give rise to all tested e-rs excent

that of the tiller of plant 34550-4.
 

~

x

3

Before co sidering tne phenotyses of the kernels on the e2rs \ 3
yt :

Car bla day belle, 0! =

“

2 : ~ ~ rc 1 x 3 a . “SY
entered in tables 5 and 6, tno e produced fron testicrosses types l, 2, S
os

 

snag gabe). A AS
gagnnese woods 4 il C dugas-t | .
cat and 3, % a plant of the constitution 25) (cless IT) Bt/a,™ not
fic the
Wx +/wx Spmfactive, will be cousidered as the data obtsined £ s

a owe Vaya A Wr tomdudrod unity KG
Whthoit may be cous red with those obtseined fro. the erusses of plints
A

ind 6. this plent, 73034-4, was derived from 2
till-r-2 of hated Spunk OG PY Wire
kernel on the self-pollin:ted evr of,plsnt 7109B-2, ,adescribed on ps te °
Uiahyimramer cy this fait iuteote dot of Lo abaiked oicvclepuset wilt ayy SMa ta iD ache flew,

The phe oty pes of the kernels on the three testec e.rs of t is (lent from

oe pctv

entered in tables 5

a

é

YY
yee] use of pollen tester slants tyzes 1, 2, and 3, ae given in toble 7.
4 a ~

wilks of the first enr of the insin stalk received sollen from slant
7308D+2 (tyoe-3 tester) that was ae bt/a,bt, wx +/wx Spnfactive in
~ A

was given

constitution. On tuis ear, al: 3 ratis,of uniforuly pigmented k.rnels
mw tiny

to colorless kernels with s.ots or scecks of piz:nent. among the lstter,
4

there were tnree distinguishable cl:sses with res ect to number and size

of pigmented aress: those that exhibited a mum:rous pigmented snots, @

( -
Rewe A Wwe [gue ~ |
number of w ich covered a lsrge 3rea (2 Som pattern), those that
A
a Apdo ae |
exhibit=d a number of piznent.d aress, all of which were small ins
CALL dace ~ 9

.
("2 3pm pattern") and those that exhibited oniy sinall specks of Sigment,
4

A (Ace bow —)
and often Yery few of them per kernel ( "Bigh dose -ym pattern’). the
4

a

rea

distrim:tion of «x and wx among the 4 cl-:ses of keels on t is ear
“A

30

indicaved that plant 7308:-4 carried an sesiwe Spm that was chesel; linked

und Heat F wer in i cebine plone wa Yar ecclr Chee Seve Tee Cen for

with wx. “+ slso dexonstrates the effect of dose of vom on pattern of
A
pigmented s.ots. The class with the "1 Spm"! pattern received its Spm from
poss
the male parent. the class with the "2 spm" psttern received its spmg

from the female 9:2 ent as the fenale cortributes two heploid nuclei to the

endosperm. the class with the "high dose Spm’ psttern received two Spm

A

elesents fron the female and Woon ele.ent from the male. sittin e ch

‘
hes puspedad bogey
of these classes there could be @ few cisclassific tiors with regura to powute

origin of Spm as £RE cross=s types 1 and 2 will illustrs se.

Cross ty.e-2, conducted wit the secund esr on the main stalk of slant

wit cuiln ad wwe ww Wt low tual
~resence of an active ~pm i teiso mies that Woe
“ Age

7308a-4, a.j-lin showed tne
chesety linked with wx. anong the 129 v riegctec k nels on tis ear,
two exnibited the "nigh dose spm" pxttern. Tests of plants arisi , rom
kernels of this tyve on ears of “lon.s 42 ving one Yom h ve denonstrated

“oS

Vue
that they ‘cea ry more than f’ Som in them. whe origin of the extra spm
A

the
ney be atrributed to,transposition mech nism.

she tiller ear of plant Hgos.-4 was used in a ecrose sith tester ty e-l.
a ratio of 1 unifor ly pigmerited : 1 veriesated Kkorrel appe ved on this
ear. Amons, the virieg:.ted ker els, one exhibited the "1 som" pattern.

It is suite probable thst the ce is of the endos erm of tiis kernel h.ve
ie

G

only 1 Som in them becusse only one of the two nuclei delivered by the
& wt

T We Wuardag Cudenyowr muuleso ceuleh pee

female sanetophyte cxrried an ~pm. fhe other nucleus : h ve lost “om
a2 A Bi A z

through the trans osition mechanism auring gometoshytic develosnent.

au pay qt peu OAK prqucub acd, Gert Bioo ,

if a plant has no “pm in it, tiren with testcross types 1, and 2,

ail at? (cless II) ensr-ing k rnels are uniformly dork pis .ented. NO
vVocleg: ted kernels aupe cr on these e rs. If, nowever, tke tester sisnt is
uppens A,
. . m1 . . . . ;
Gf ty ,e 3, then half of the a, kernels are uniformly dark pigwented and
ath are vafigsted: colorless with svsots of vigment in them. the phenot. ve
» XN /
of the kernels on enrs of no *pm plonts in culture 7456 (ttle 5) ana of

4 olants in culture 73084, when crosses with tester plants of tyre 3
“w

‘(thet is, plants 7308D-1 or D-2) are given in A of t=ble 8. on the e-rs

of the two yvlants (7308a-1 and i-2) th t were at 3t¢/a,m-+ Bt there were

wD

432 uniformly dark colored kernels and 4@4 kernels thst showed colored

areas in a colorless bickground. anong the latter, 402 exhibited mary
C\Spu. pain )

pigmented spots, some of wich were large in area. “ithin these large
pigmented areas, smaller colorless szvots were present (see figure ).

two of the v-riessted keenels exhibited only small spots or sseeks of

( & > Fem palow | ,
. 4 ti- . . a
pilguent. Among the 953 Ay Bt carrying kernels derived fron the cross
A

te thy Water Oy0 -3 Haut m AA Ueor?,
of the aut Bt/a. bt plants, 475 were unifor ly dork pigmented and 478

were colorless with soots of pigment in them. In 468 of these lutter,
ce,

wa
ta

there weve many pigmented areas, = number of which were large (1 -om
pettern) and in the remeining 10 v.ries:t2d kernels, the e were fewer
pignent=d ore s and all of them vere small ie=seea (nore than 1 vom).
amon. the total of 1789 Bt kesne.s in t-sle 841, 907 were uniforrly

oignented and 682 were vseriessted; 870 of the viries ted Kernels exhibited ~

the "1 vom" pattern ond 12, or 1.35.5, exhibited a vavtern exore. secr when

more then one som is present in the endos.erm. +t is evitent tht stiong
(ta Boker Gye -s land)

the Spm ca rying pollen », rains >roduced by wlents 7308D-1 and D2, the
A
Leceed Ww,
vast majority hivk only one Som in each. It is also ole-r th: vo ne rly

aw Spur us af We (have Wweo Pract

 

 

hilf of the pollen gr oins t1

smong a tot-l of 5040 pollen grvins th:t coule be tested for this in crosses

a

to 23 plants th t hed no »om in them, 2577 poiten -r--4s Eve no evicence

Cond?

of -pm in any one of the.: wnereas the revzining 2463 pollen gr iins heac-an

Oud Quurug tatu

 

oetive Ypm aoproxinn cely 93 percent h.d but one ~pm.
The remeining 2 p reent had more thin 1 ~pm in e ch.

The types of kernels asve ring on the e rs of slints in c:lture
7455 (t ble 6) when crossed b, tescser lants of ty-e-3 (plents 7308-1 and
D-2) are enter:d in © of t carryin. kernels on
these eors, an avproxim:.e 1: 1 ratio was .iven of uniformly visgnented

7

kernels to those that ha& pliliuiented s ots or srecks in a cslorless bucxsroun
aw
betwk © in the tillers tn

23

the Letter kernels could rexd

Ou

lilly be cistributed | on the basis of oxttern

of pigmented s-ots,int» two mein classes: tnrose th t exhibited = number

of spots of »igment, some of wich were large in area (the ‘1 som" pattern)

and those th:t exhibited a pattern th:.t is ‘oe .r when more than

 

1 som is present (see figures ). “he ratio of th:se two clasces obese

acproximised 1: 1 on the majority of the e rs, .s snow: in the t ole.

k

4

that com was present in these plants but in its i:-etive pnase in nost o
Cures cull tay kml, Leelee aval Vivant ©

~ oe - . 3 7 oN

parts of the plant was mide evident by the azspe vance of sectors, usually
we <b? quate, LED be -

1g a 4) ee =

to its sctive

 

uhurttlaly

phase. these sectors were non-plgnented or non-pi, sented woth soe small
A

vats Woon

strevks in wolen pisment was present.

mong; the ei.rs of plenss in ec lture 7455 th=t were used in xiking
test.cross tyces 1 and 2 (see t cle 6), taere wos no evicence of the presence
of spm sions the kernels of 6 of the 14 eours. its oresence was mde
evident in so.e kernels on the mxxsxmfxkke remaining 3 Ke rs (t cle 9).
aves Purclud Tr Lor

Only in the cells of the tiller es of plant 15 oee Wee som in its active

Ws whys egwew ty Spur Ub wr da Angeb ye em, ands Uses Ve oneQet To

phase. In 211 other esrs, =m entered the soft ve ohise omty i: some
. A A
ceils 1 te in developnent of the evr or durin: develo scent of the kernel.
A A

“he syubols describing the beh vior of Som in different = ~ts of the

clants in culture 7455 placed in table 4 (te-r 1957), ase b sed on the
phenot. -=s of the kernels derived from the t

+hn.t the design tions of opm ph se in this t

litersoret tions of the origins of the phe. ot
poduend) bows hy dL itubid Gov ereerto ,

ears co -eS fron sunil r tyoes of test cordus

7456 (t ble 5). In the ero ses conducted v

etitution. mowever,

ox|wx, opm carryin,. plants in culture 7456.

wis known to be vx +/wx som in co: stitution

yi

in cu.ture 7§56 should atse be /x +/wx oom in

rnel from which es:ch plant in eultu

on pase °

Fl Mu
pages _

Pg wets (teo-e an a, 8, ard # of
twelve olen s were

elther b the a pe=rance of the lsnt or by

derived trom test crosses with euch,

f

O
“he, ty -es of kernels asoesrin., on the ers o

5 wlWaiscussea e.rli

ech suc: cross wae entered in ». of tuble 86.

hy
from testcross types 1 avd 2 vette PH

twelve tested slenis weve deriv
[8 @ciltue).

ixf/ Wx and in none of them was any evice.ce

Bt/a bt,

est crosses described ibove.
‘ble 2re biased on correct

yoes on the deseriped—testeness

t oc vith the plents in culture

ith clin s in cultu.e 7455, no

Ay

the inactive Spm with #& in tno-e pl-ts

such evi.ence wes  iven by the

the oc. ent vlent (71095-1)

thi Hage

and mes of the nx )ax olents
ra

re 7456 aro .e as deseriped
ec. fron univor..ly d-rk

“~d

Wize of these

given,

 

£o these plants.

er, anc the a@ata outeind from

pee

eunOne thie ale e a outzined

f * Ow nang taf Ne we
: . FD)
xf plontsy no

ns
37

evidence wo tsoever was given of the p-esence of “ym in any cue of them.

there wes a tot 1 of 3107 k--neis; 1484 were unifor..ly dark sisnented

ee
ee

(E415 Bt : 69 bt) snd 1533 we e tot:lly colorless (79 £t : 1454 bt).

. 4 - gt | r—L _ as »
+h=t the e plin.s carried the class II st te of & 5 th: t wis encavle of

resvonding to tne presence of an active ~om was snown by testeross t, 5e-3 -
conduct d wits 6 0 these 7 plants (4, + Lle 8). “he reuai ing 3 of the
dé tested slants thot srose from the unifor...y durk pigme. ted kevnels were
iX/ WX. wO evidence of the presence of Som was given by yvlant 74565-6,

either by the sppe rance of the slant or by testceross tyce-l conducted

with the one fertile esr it sroduced. Poth of tne other two »lints

(B-5 and 2-2) were .x +/wx Spm. All 4 of the plants in 7455U anc all 6
of the plants in 7456) carried vpm. Bight of these 10 olanis were
Cc-1 me d-4)
ix +/wx opm in constitution and 2 were ix/ix. Soth of tne in ter 2 ul .nts

,

hed one »pm. It is prob le that the »-om in e ch of then was loc .ed

close to wx in one chro..osoe 9 but pro eny tessc wo ule be revuire to
aet rouine this, and these were not co ducted.

testcross type-3 was co: ducted with an e r of & of the 10 xxxxtxxxxxzm

ix/ax plants in culture 7456 and with each of the 2 th t wre ix/f/ax ond

A
BA
ec rried ~pm (plounts O-1 and D-4). In t ble 1oX is jiven tne one otyvoues
“A

p 1 ye : 3 3 1 m— *
of the kernels on ears produced by the 5 ay "Bt/a 5 bt sx/wx ol nts
J .
thet wee subjected to testcross tynvne-3,
phe ot-ces of xernels on the e:irs of tne

thet were subjected to this test. Un e

m—- :
a1 carr, ing

Hite

aporoxim:tely hoilf of the a,
a

ae

oslf were voriez;.ted in th:t they snowed

38

and in B of tuple 10 is given the

two wx/vx plonts carrying vom

sch ear in «= of tiple 10,

ke nels were fully ojigmented and.

elther many svots of cignent ina

colorless bockground ('1 opm' pattern) or a few small szsots of specks of

pigment in a c:lorless background ("hich

dose" “om p..ttern). The

distribution of Wx and wx amorg these two classes of v riezatecd korvnels is

strikingly unegual. the gre t mojority

DO

"1 Spm" pattern of piguented spots whereas the gre t mejority of

exhibited the “high dose’ pon pattern.

majority of kernels exnibiting the "dirt

(2 x to 17 wx). If the ls ter kernels

fre-uency
pigmented class of kernels,

pigmented, sx, kxexmekm, 206 unifornly pi-

NG

it will also

the rgkxo ef tyoes would be:

of the «x kernels exhibited the

wx c<ernels -

Cu

th-.t the

CS
oO
b
pn
oO
et
oO

se-mocstled" p.e¢ ot se were wxx
are combived wit. the unirvor:ly
of «x rnel

207 uniforuly

mented wx, 200 variege ted fk .rnels

. : . + v “ on f 7 ~
exhibiting the 1 Yom pettern of s-ots (178 “x to 22 wx) and 209 k rnels

+

exhi bitin, the "high dose" spm patt-rn of

+t is quite effigent thit a f ctor chesety liked with wx (11 crossove units)

oincnented suots (24 x : 185 wx).

ax yada hark

a

A:

in tnese plants is res-vonsible for the "high dose" oon pattern of pi-.ented

s ots in those k rnels thut received an active »pm from the tyoe-3 tester
Al
Wo

pollen psrent. *h.t this is som in its insctive phase in the cells thet
give rie to these e:rs co:ld be sus ected as the p-rent piont, 71O9*-1, wa

ix +/wx Spm in co:stitution and Spm was ckeeeky linked with wx. also,

CY titeombunlioy as WOAV¥
~~ ~
the cressever percet between wx and “pm is simil-r to th: t given by
AA A

plents derived from the tillers of pl nts 7109B-1 snd B-2 that weve
igi OGLE

wx +/wx opmfactive) and iliustruted in tests cunduct:d with plant 7308.-4,

A
alae
entered in teble 7. Theat this fuctor is opm is shown by the vhenotyoes

of the k rnels on 6ars cf these and other ‘ix/wx plents in cuiture 7456

that wee produced from testcross tyse-2. the tyses of kernels on the
ears tiuis cross produced are entered in t ile Il. It will be noted in

»this tcble as well as in trdle 12 (from testcross type-1) th.t the ke-nels
on ears oroduced by the main st lk of these plants g2ve either no evidence

Le evicent in only a ver

on

of vem in any oe of them or its presence ws ma
few kernels on aner. Un the eurs sroduced oy the tillers, siany nore

. - . . : , ak.

kernels showed the presence of “om in them anc the numo«r of thee increased

progressively, the later the emerzence of the tiller fron the bise of the
In otzer words,

plant. , the younger til ers had more such kernels. amons the kurnels

exhibitnng »pm, li k .e of it with wx was cle rly expressed, snd it occu id

sda

ve loc ted swvproximste y LO crossover units from wx.
A
az”

AL

the evidence obtained from the testerosses described 2pove makes it

obvious tht union in the vorintwrcy endosserm nucieus of two nuclei

contributed by the feusle ¢ cmetoosnyte, in exch of which an inactive ~pm

is present, with a nucleus contributed by the male gemetoonyte in which

=

opm is active, will give rise to a kernel wioce aleurone layer will exhibit

a pattern of pigmented specks in a colorless background tht mimics the

tt

oo

pettern produced when 3 active ~pm elements 2 e i.troduced into the

<

‘

prim ry endosperm nucleus. aS tidie tceco e rli r in this resort, the

inactive opm under these circumst*:nces, does not underso th t p rticulsr
type of genetic alteration wnich is resporsivle for 2 true charn,e of its
phase of activity. It exsresses, followirs meiotic sesrezaticon from

p

the active %pm,the sane Li active phise th t it previously hrc ex ressed

before being associated with the active von. at present, there is no
. oo, otirtuck ; oR Aina
evidence to indicate the level of:exres £ pee comnpleuent tion tast
i gu, . . or - ;
Gebls an in ctive and an active »~pm exert -on-oneanetker. tiovever, it is evicent

t aut,

thet this must occur at sone level in these cells, and the fict that this
eseurs has m ce it sossible to test for the sresence of an innctive “pm
in ports of slants tht oth -wise weste give no evicence of the presence

in the: of any Yom elesient. Taltey 1S Md | (4 Saya 9 AG Afpeh tee

_ Cun lint, Cruaduet of wee) thy bob WOW 5 plould "F307 D- ; »y- 3, opbhinucd!
Lume Uaenss “nlndy Weel Chew plowita nity te a Olen 1937.
Al
+he tests co sidered so fur hve delt with the bei: vior of vpm in
subdseiuent generutions following two cises of caange in picse of its ebivic
from 2ctive to inuetive-- and registered originwily 2 tae mai: stslk of

plant 71098-1 and of pizent 71LO09U-4. ashe supose uent bensvior of the
inactive som in the seecund snc third generition »ro-eny, 15 suvom rized
ina of tivle 2 for th:t originally oresent in the main st:lx of lent
7LO9B-1 and in tublie 4 for th.t origiuatly oresent in the main sv lk of
plant 7LO9U-4, the origin of tne piants enteved in these t bie

He, along wrt

se of e oe ae -well—s+s tne aope rance of the «sernel from

don uveel fs dy AK

mn

lidile. ved at the b.

oO
fin
cE
th
i
He
49)

c

wich e-ch (lant srose. +¢~ may be seen th t the

roth) ceebr 4 toe pLoutty

covtinued in its in ctive phase in subsequent seneraglo s ana th.t return

an fequadl , <b

of it to the »ctive p se wis mach Helayed Tm—tne pro eny «li nis, the

elas

event respon nsifle for this occurring ony in see cells, and ofte:. restricte

 

to tnose of the tillers.

me wy “tet

the bens vior of opm dwived from tiller-l and tiller-2 of pl ont

ay
7VLOOB-1 contrusted sre-tly with the beh vior

.

wi
-earof the msin st

cenctuyuld ty be npontd wa Aulbepenodll reotailioup

Vomp rison of « with © and ¥ of table 2 will make tis evident. it should

   

be st:ted here thst pollen ec llectced fron the sume clant was used in mixing

crosses to each of the ears of vlant 7109¥-1 =nd thus, the difference
in behavior of Som in the proz;eny derived from kernels on the e=rs of
this slant eannot be attributed to sore modifying fuctors introduced by
the male povent. In the »~pm crrrying sro.eny Gerived from kernels on the
err of the main stalk of pliant 7109B-1, Yom was in its in ctive p se in
the cells that gave rise to esss in all tested ports of eich lent en
renained in tais phese in successive gener. tions ss snuown in **, tole @,
uncer teers 1957, 1958, and 1960. In co..tr st to teis, Spm vas in lvs
active ise in the cells that gave rise to the e.r of each of the tillers
of this plant (t. le 1) and it wis in the setive vhase in the celis that
gove rise to miny of the ears in the opm carrying »oroveny of tillers-l and
-2, 28 shown in 5 and © of teble 2.

In B, tsble 2, uncer subhe ding “esr 1957, culture 7306, is shown
the ohase of sctivity of Som in the cells thit oroduced e-rs on eight

U2

Yom carrying olunts, € ich agerived from 3 kernel on the evr ov tilier-l
A

nN

a

of pl nt 7LO9b-1 thet shoved spots of aisinent in a eslorless b icksround.
the slents in « of culture 7306 grew from kernels thet haa many siill
spots of vliement in © coiorless b.sk.round. “he two slanis in B of
culture 7306 were agevived frou tee two kevneis on this e » that exuibited

only 2 few specks of sisment in 2 colorless bickground. igich of the

Six slants in a of culture 7306 had one “om and itswas linsed with wx in
45

ive of these oinnts but was not linked witu it in one slent. “oth of
the slazts in 3B of culture 7306 had two Sym ele ents, one of waich was

linked with wx. in plant 7306B-1, the sdaitional Som was locived close

in~1

to 25 in cnromcso.e 5. som wis in its active pho.se in the ceils

that enve rise to 15 of the 17 tested e-rs of the »slrents in culture

a)

7300. testeross tyne-2 produced so.e of tnese @ vs ait tue pnenotoyes
of ke nels on the exrs produced by tis cross are entered in turle 15.

In tuble 15 likewise ere entered the kernel tysoes aove ring on the

a
RQ
©
3
ad
<i
©
OQ
rh
5
O
to

ers of six ol: nts in culture 7560, e. ec: oF wich was
vorie ated, Bt, “x kernel on the first e r of tne main stalk of slant

74306.-1L. In two of t..e six plents, Som was linked with x. wae one
t ’ }

fertile e r sroduced by cleant 7560-2 gxve no evidence auong its

kernels of toe presence of Yom in any one ot them. +ne pne otype of

the vlant,nevertheless, indicted thet opm was oresent in teis plont.

In the remaining teree olnonts, derived from the recoubinent class on the

o>
parent er, Ysm was not Llisxsed with ox and in one olint (7560-4) two
Som elesvents were present, both in the acti e whise in tne cells tht
eroducec. the two fertile esars of tnis plont. seither of tiese oom

elernents was linked with vx, hovever. from the locxtiens of som in the

plonts in culture 7560, it esr

vhecrs thit the rete ov transzositiun of vpn
ma

in the prrent olunt, 7306A-1, was mucn higher taxn encountered in plont

hy
i

t

U

r
oD
bh
17)

of related cultures. the p-reent of the recoubi.tnt classes o:
on the ers produced by iIrnits inc iture 7306. was high, be.ng 18.5 nd
tis miy be a Feflecti.n of the hish fre uency of occurrence of premeiotic

v

trins:ositien of erm thes occurred in these olsnts.

In 1957 ol nts were gvown under culture number 7307 from kernels on

the esr of tiller-2 of plant 7109B-1 and tne ph:ise of ictivity of ~pom

having “pm

in the cells giving rise to tested e rs o these plonts,is shown in v
oF teble 2. the plants in a of culture 7307 were Ges ved from St) ox

ko - els thet exhibited a number of smell s-vots of oigment in 2 cvclorless

backsround. +he slant derived from e:.ch was exnrect a to h ve o-e Yom
: 2 t * = . ~ ~”
eélenentin its cells. +hose in B of culture 7307 were de ived fro:: tae

four ko~nels on tzis t .ller eur th:t showed on y a few specks of iguent

in a colorless backround. Lhese ple nts co ld h:ve more thin ome
oom elenent in tnem. Som wus in Lts active phase in the ceils that gg .ve

QD

rise to 2il but one of the twenty-six e rs tn t tne ¢lenvs in cultu e
7307 pvroauced. the six clsivs in « of culture 7307 enc. hed one ~;m
and it was linked with wx in the five plents tha:t vere «x/wx (line l, a,

tible 16). Slant b-l ha oniy one som ane it also was linsed with wx.
slants 73075-35 snd 5-4 e-ch hic

nN
8
Qu

with wx (Lives 3, a t ble 16). the o
Ke nels on the e .rs produced py ocinnt 73075E-
ze-mel from wich tais plont «rose. Urb FoR
or specks of

alsnent in a colorless bosnczg ro.

testeross tyses L and 2. Spa was Linked wi

a, teoble 16) but the recombi ation fresuency

by sister plants. Chiuasge in piese of

5 also, Ag
duri:s develourent of both plent ina k
sister olarnts.

Voerie, ted xurnels we e se.ecuca from t
st:lk of lant 73078-4 and grown in 1958 und
vem in moet of these slants be: ved in the s
in the osrent lant. +his was snuwn by the
onuwise in »nuse of som, -- fron active to ir
s-me degree of incressed fre weio.
(line 9, .:, t ble 16).

Un the er or
ent in

souie kernels exhibiting ssots of wis,

in the rec wbhluint cl«ss (.x) were Srown in

two vpm ele.

ents, one

nerot. ne of

2 was sini

nd An. vs3 e

th wx in tu

Was gsreate

Yon from

ne  7ea aid

r ciulsure

Lhe Tbeiiner

L Avboy be

the main stalk of »eloit 7307.-3 and of on

a e@olorles

1958 uider

d in then folloving ©

ant (lire 4,

im
n
ro

r thu. th:t siven

uetive to in etive

eriel oeecurred liter than it cid in

e r or the misn

nunber 7572. agi
as Lt ad beh .ved
oF geecurrence of

is wel as by the
Cr.Cen von 2nNG Wx

thal
rt $3071-5,

ret

S

DAG SPoUNG that we

eceulture numoers
7561 ond 7562. the ohase of activity of »om in the cells giving

rise to the testecd ers of the clonts in tiese two cubtures is recorded

an

in © of teble 2 under Yeour 1958. AS indic:tved by the adits encvered in
lines 5 and 6 of a, toble 16, opm in these slunts was Linked with Jx.
The first e r of the main sl.lk of plant 7561-4 was sectorial.
In the cells givi-g rise to eight adj cent rows of xerzels, vpn was
kKactive pz .se anc it wis linked with Ux (line 6, a, t ble 16). In the -
renal. ing four rows of kernels, no evidence wis given of the .resence of
opm in any oue kernel (line 7, --, teble 16). In the summer of 14960,
plants were grown fron v rie. ited, Bt, «x kerneis on tris evr under 1 2nd
Lt, x

B of culture 7777. fully ocignente,xernels from within th t p-rt oftue

e-r th.t g.ve no evidence of oom, were sown under ¥ and ~ of cu ture 7777.

oach of the sixteen iunts in culture 7777 hid one som which was li. .ed wi-
ox ( C, teble 2, ter 1960). «11 plants in U and D staw¥ed develo -rent
with som in its in:ctive phase. Uhange XmxXEKEEE to the rctive phase was
mich aelayed as evisenced by the 2 pe:renece of tiese plants. a Lew

suall sectors of nonpizmernted tissue were ocresent in a few of tne le ves
on the main siulks of some of these plunis. the tilers of these -lints,

nowever, had more such sectors. “ollowing tecteross t,ce-2, ten ears

were obtgined “rom tne slants in 77774 and J but in only mkmmz 9 of the
rb . “ , . . . a 4
1085 a,= carrying kernels on these eurs was evice ce given of the
oresece of -om, and 5 of tnese 9 kernels vere loc ted within a simll
sector on one of thee ten errs (e-r of tiller-2 of clint 77773-2).

all

KG

kK rnels were JX. festcross tye-3, conduct.d with ti. e slants,
indie: ted that eich hed one Yom and thit it was Li xed with /x. alliong
596 a et, Bt kernels on these ers th-t received Spm from the pollen
parent, 296 showed the "1 Spm" pitt rn of Jismented ssots in a colorless

backsround of wiich 7 weve wx and 289 were wx, and 300 shoved only a

say)

few specks of visment in colorless background, tue “high dose! Spm

outtern, of waiich 284 were Jx und 16 vere wx. the ».reent recunbl ation

a

between opm and Jx,

4

b2sed on the ratio of vx to wx within ececn of teere

p!

two classes of voricgatec ke nels, is 3.6. testeross type-2, co. cucted

With the lentes in «» and 5 of culture 7777, in woich som ves i its

active pnuse in the ceil

a
ct,
om
PD
Fy
je
:
QD
ck
oO
mM
Oy
oO
ty
)
Oo
;
ct
r
r?v)
©
-
ms
ct
G2
“ee

likewise showed th t oom was liv ited with «x in these ol alts und thet
the p reent recombi ation wes low. un Sixteen eurs ocroduced by testcross
iu=L

teoe-2, there wes 4 total of 358 25

a

ecaurryin ke nels in wi.itch the
or sence of om was evident. anon, then, 3832 were /x unc 26 were wx,
thus giving 2.9 percent recsmubi 2cion bet een eon anu ox. +his very

in

Q
by
o
o
F
in
on
te
Bb
et
G

low peresnt of reeombinatiosn was ex ibvited on the

~)

cyitere 7777 res rdless of the sh:se of scetivity of Spm in the cells that

wo
gave rise to an evr,
 

47

   

“

¥dn collected from plant 7105B-1 was used in mexins

Kl
Or
es
S
©
5

of crosses. clints weee grown aurius the suinuer of 1557 only fron

kernels on @ars cerived fron two such crosses. The be. vior of oom
. _ ; a re . oe : , . . r -
in the olants thet-curried-it: is snown in D of t ble 2 uncer tevr 1lsd7,

culture numbers 7312 2nd 7313. the slaits in czituee 7312 ecume fron
me whl vie S pow wer faded

Bt/a. bt, ix/wx. the
= A

. , tL
kernels on an er of a clent tht was a5

olint beloiged.to class I, -nd ivs stv te wis one that

}.
rm
et
ie
ao

gives rise to unifor ly pale-nisuented kernels when oon is aoxe:t or
wuen it is voresent b t im Llts inective onise. In tue erese.ce of

vom in its active ohase, no cigse.t ipce w in either slant tiss es or in

Cy ¥
Were Uren AW
the s<exrel until @ put .tion-ineoct.. event 9 curs whiciu 2ives rise to a
A

bhigner saLlele of a, thet is theresaftcor stiusie in ex.ression is tue

he)

Ra,
vLuTls

presence of an active opm or wien Som is absent. to<se mut.

4 ~ 3

oceur 1 te in develooment of tue pblent tissues 2nd asiso late in develono-

went of the B@madosperm. aS a conse uence, the fre uency of acsne ronce

ermin:zl nutction is low on tne e rs of sLlints

so
cS

m-L

P Be °

o
al
Fy
s
<j
bh
oy
ct
tw
tn
no
ci
cl
1
Cc

culture 7312 grew exhibited tie presence in exch of the clrss I st te

~1 © mL

m “ * 1 ny 7 2 a ToT . :

of Be ycerived frou the female 9 rent,and the cless Il ss te vo

AL wot fur haut 109 B-1:

derived from plint 71095-1, “nd e-ch h @ opm in it. fron the aopeuranc
\

 
 

 

48

of the plants in cuiture 7312, it wis evivent tn:t e che. ried som.

if a
-owever, the tested e r of olunt,l and of plaint,3 g2ve no eviuence of

Qo

on each er.

the vresence of Som anoig ties Kor.els, the testec e rs of slants

Ausvber 4, 5, and 6, hovever, did show tne sresence of ~pm in so e kernels

wees %
; 1 : 4 m1 y 7 = n-L
on each esr. flont number 5 proved to be 5 (cliss I) s5t/ a»
“nw
bee Ruta (ult S
(cluss II) Bt, sx +/wx Spm in constit tion. this was si.m by the
A

phenoty es of the xernels on the one fertile esr it produced in a
cross witn a slant ao.osygo.is for a bt, anc wx and having no oom,

“oO?
among the 128 ¢x ke:rnels on t.is ear, 117 were unifor..ly sclsiented§

62 pile pis ented kernels carrying the class I si-.e of a{ 7 and 55

dee, ly pigmented ke. els carrying the class II st. te of a .

the remaining 11 «x k rnels were veriegated. woeven of these had the

~A\
vy ao
4 T m-L ;

cliss 1 st.te and 4 had the class If st.e of a, . amore, the 124 wx
A ce

Fue
xernels on tuis ear, 7 were uniformly pis: e ted. sk of these weve
pele pig.iented and e were ceedly vcis.cented. the rewai ins: 117 kerreis

in tne wx cless were all v rievated. in 68 of tuese, the cliss i st ‘Se

o . e t ~ ow ti
ofa Was present and in 49 of them the clnss Il st teo a, TS

uinkage of Yom with wx was evicent and
sxhusx 9.8 p reent ov the, ert

   

present. Sor tuis er we.e iv the

a

recuiubli ant classes.
AG

5

 

slants were grown uncer culture nuzver 7547s
. am woe
. py Pr
of kernels on the above described ear that
“\
In adaiticn, 3 plants we e grown
3 £ nD
sed ox kernels thet

wu

n-1

the varle
iturve $§47

opm in the

r

in 1958, five
sted «x
te of a5,

st.

the vari
Pron
eich plant in
Pte

given in vD of

v

from
carricd the class I
uncer cultuce nuuber 75478 and Uv
had . ; a ; mL
gxxexrxegt the class Il st te of As .
carried spm,linked with Jx,ancd the hise of activity
cells givitg rise to the tested eurs of these rlents is
table 2, Lt will be noted th t aly in 5 of the 14 e rs obt-ined fron
olants in culture 7547 wis spu fully active in tne cells t.. t srodauced
the shenot ses of tue kKevnels on t ese errs ave given i:
ers, the oresence of vou was exnibolted in
8 Show. in » of v ble 17.
Y2S uSed TN aA cross

cL ot 7547 .-1
cond carrying one von in les
aermels on

oO

taese eirs.

tue

of
: 1)

tsble 17.
WL Soe
WK y

Es

or
only so.e of the “ernels o1.

Fees e r of tie

t suulcer 7538-3).
SA

i

ani
Loy,
(ols
Vere

bt,
pnenot,
io

Bess
Gig anil - pablancliel car 4 Au TEC? D-2
+he
“i014 the as.

Leniented of whlen 37

showea MMEARLXAX XANOLAX

“he
lant homozygo.s for
: ’ ; o x
azwiek UW
an
tne

i ob A...
s of

o2zle

aa

phase
esa inv ta tle 17.
Cunt
aowever,
ae

active
qe enter
rnels
iX und 42 were wm.
F ta

with
ax

Gills ecr

carrying kurnels,muxz 70 were uniforuiy

35 wele wk. among the 7O «
m in then, 38 were

9 OY
pattern of piguwented sare s in 2 colorless buckground in mos5 o

ane

presence of os

the

 
 

 

50

kernels different from that of moct of the wx kernels. in the «x cl3ss,

here were 2 nunber of deeply clg@uented spots representing mut:ticns to

AD and they were rether unifor: ly distributed over the sleurone layer.

a

in a few of these Kernels, KEKKXENEKK 4 very sSuall cale,s.ot wis mhxexxedx
also present. In the n-jority of wx kernels, in -daition to deeply

is, a non-pigmented backround
pigmented s ots,:risixg from mutation, there were 2lso tiuny areas
exhibiting the vale pigsent:d phenotype in nore of walich was there a

coy wa «ost
Gee:ly sigmented ssots. small colorless are.s agpe red in maxx of these

lerger pale are-s and in 2 few of these latter colorless :reas, a s..all
speck of deep pigment was observed. <shis is the £xmmxmfxxm cheot.ve
_ 4 Us son £ . . ~ + ~ -:
thst wo-té--be expected to 2spe sr if the tanjority of wx kernels h.ve o.iy

. 7 atr-Y on.
the one 25m in them that was delivered by the male
J A

Hi

ent. the sale

ro)

are s with colorless s.ots within them wo 1d revresent the sltern truss

 

the
phuses of activity of osm a ring develo ment ov the kernel, from,active
phase at the Linitietion of kernel develo.uw.ert to $.e inactive duiscse in a

RW
cell ewrly in endosvern develowucnt and = return ty tue active shase ina
A

wescendent cell L-tver in development of the endos»vern. the pnenot je

exiibited by the wa jority of kernels in the sx class is one tnat aa,e vs

when three active “om eleuents are present in the endoscerm. few if any

. as Ueda le @ RO

orle oivzented ssots Wu Le be_ tye oe evicent in then, 44
ah av J

uuu Wado wikloht rf Tew Woetiy be waned