Reappearance of a primitive character in cotton hybrids

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Title:
Reappearance of a primitive character in cotton hybrids
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Book
Creator:
Cook, O. F ( Orator Fuller ), 1867-1949
United States -- Bureau of Plant Industry
Publisher:
U.S. Dept. of Agriculture ( Washington )
Publication Date:

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aleph - 29621647
oclc - 30801957
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AA00020775:00001

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lts' ltd Nov lut'll| r 7J, l h.t



U. S. DEPARTMENT OF AGRICUtTURETl
BUREA" OF PL',ANT IN Dl'STIRY-C'ircul:r No. 16.
B. T. GAI.LLOWAY, l'li<'lf ot iirriui,



lREAPPEARANCEIi OF A P1.IM ll1 IVE (11ARACTErIi
IN (OTTI'ON HYIIBRII)S.



lin
F. C()()K,
BTONJOMIST, IUI'KA( OF1' PLANT INI)D'STInY.


)o01 --(lr'i. is-)s




















BI 1.' \U OF PLANT INII*-Tl1Y.

l Ti oK/iisit Mil PahoI/%i4o4/. ald Chief of Burtau, Mi evrly T. (Galoway,
I'hl', i l.; n o d I'atholo,/ist, a ad Asisltantl ( Ictf of Ru'rcu,t Alblrt F. Woods.
Labioritot of Plant PatUilinniq. Eywin F. Smintl"., l'tlhio'i't in (Champ.
Inusgtigations of DisAs os of l'uits. Merlon B. Waite. l4 llolopist in "'' .-
Loioraitornj of Forest I'alholn/yi, lHaven Metcaltf, I'alli l<.ist in hargae.
(' tion o ant Truck- Dism,.ocm md Planta I l)it a' ,'bi'i 11. 'Willin 'T l() i,i. l'atlthologlsti in
I 1 .r 2.
riant Life Histor! lincit itit iioni', Walter T. Swix l'-i', I'hyi olo ist in i .
'i/oion IUtc(ili/iai I ittxii'ltitniN, Archibald 11, Sliamn, iid l)anii N. Sho min ker, l'hysiolo-
g'ists in Charpo.
Thoiwco nt'rci.<;yf(()i.a Archibald D. Shamel. Wihtian W. ;iirnor. atind Ernest 11.
Alaitlirs<)n, in x 1, .
orun Inrcstigotihwix, Charles P. artley, tPhysioLogisa in Chiarae.
AlkIali and Drighlit MAi at/aI l'anit lrvcdi/i Itt iiIriti attio"., 'Tlomas II Kearney, l'hysi-
olngist in CMul'e.
,>oi I actcriologi/n and Water Purfalitio n lrt'siiliotiiinx, Karl F. Kellerman, Physiologist
in lin'argC.
tiontomic In-rcstiiaotiois of 'l'ropical and Subtronpicil P/lants, Orator F. Coolk, Bionomist
in C('hlarge.
IDtttg aind Poisonotus I'litat Inroxtigatious and T70 Culture linresltigalions, Rodney II,
'True, 'Physiolo'.ist in i . -
Phyisical Laborntoary. Lymnian J1. Briggs. Physicist in Charge.
( 'rop 7wchIiinln;outI atnd Fiber M' itnt l]iislii ,tioiin, Nathatn A. Coh, Crop 'Technologist in
iliargp.
7'"'::,nwonic Rangt lieii~gr Inrrfstinnin, Frederick V. Covillh. Iofaniist in Charge.
l'Atirn ,uit lt, Uti, iii restigalitons, Mark Altred i'arleton, ('tralist in (Char-t.
Arliii,'ntt, ar p'rimi-ttlul l'inim, Icc U. tI l ihtI. li rl iciliurist in Clharg' ,
I cWirliiltR Wcstinf! (iimd( s, \Vi= i0am W Tr-acy. s'., -,',,, ,,, ,i" ill
iliar-Bct lInt'cslit ulion/ t, ('harl 0. '1It twov. ind, I'a.tho .;ist in i ii _
\\,'<:lT lr t A huit/.ll ii l /trtciiioii Ii t;'"lit/Etiitiit's. Carl S. Scofield, A rricultulrist in Charge.
Irn/-lf.antd A riaculture lIii"st {lqtxi/: i. 1. Channin' ('hilectIt. Agriucnllnrist in Charge.
'ntoit giical ( oicctions, Gustavnus I. 1.raclhatt, I'onologist in Charge.
'iht / I ,,,,, i l'nIimon jt, W iliain A. '. i ylotr :al 11. Tlarold 1l'ow ll, I'ornmologist
in (hargOe.
1.rrpirim 1.:l v (; ardns atntd Grounds, I':Wl\",ird 31I. PQyrtnvs. Sv! PA'imt('(nd 't.
t'orci/. See anid Itant Intrdiiclio.i, David Faircaild, A.rictlnural lExplorer in Charge.
Fo'iit/e ('top In litigations, Charles V. Piper. Agrostologisl in C'large.
Snid I.at/oh lvn'/, I :dlgar Browi. Uotani.'t in Charge.
(.itii Siaindurdizialion, John D. Shanahan, 1 -1- Technologist in I ...
NS l, t/./ n t.l, l':bb(,ilt.ryi and(; iui'liit, Mia i, I 'l, I V/a ri \. I -ey. W.ititologist in Charge.
I /M*), 1"ma.idwl*lien (lardtie, Chico, (it1., W. AV, Tracy, .jr., Assistant I:olinis;t in Chl ir-
SoutIh 'I'I:I: Gair'drn, I.- W*n',r., 10ward C. ("MccL. Poniologist in C av X.
Panic( rS' Ci"oo/crativc [)c, o1triil"irin FcS atwi:>ll A. Klnaii, Spj(>il Age-It i1 4'lh 1, -_
i(dt D Isirirbttlion (Directed by chief f of insteiu). Lisle Morrison. Assislatt in General
Charge.

Editor, .1. I R locikx'.ll
Chirf Cicrl. Jiameos E. Jones.

[Cir. 12
2









l, "lAl PK", ARIAXCE OF A mIMITIVIi CIIARACTFIN 1k
('01-O1 lI,0\lh


INTRODUCTION.
The fal; lt coll, dtdl, d 111 1ll1:- ibrirt' rcpoi't an i iiri l til 0rc-nls (,i*
fxp\ erim ent- iit ider(;dI>' i f' r Ili<" r I tI 'lr -o' o f :i' i i l i i I L 11 lin h
[ hired Ilitt I t. ,It'(\+il rcI -t, i t v, aLcIic- ,,f ,+ r ,n I'ri,( 1 ('cnl II Il
A m cri<'; ;li l I C' Ihn triid /:i I g' tIeI ,ith I I I Iit Il S < ) II I;ir i( 1-.
Th! (>x|)c 'i wI > haI e I I n l et Ix-cn Yan d far Ii ol o 1r+ ,3t 1'1tfrii ,o
thl ;I I r i:(l rll';>l ;1 ;il ( I+ th,-c \v; i .ri('( i I it In' I lited l t lc+ tit1t t lIeI c
lhave' :ilrc. d v ;i + l'( l'il i':r l I':t of hi l ii i rd 1r <' ; !:i l itlri\'s .
I t is ,thqll iont l tl d II tlI It vl ti\ ld I n ;i) I n i lviI l'r !t !,irf w I;; I(J'(' )f1
,sl ow i l n l(" i >il h n i riniit i\t, 1* 1t11i4 '111rV ir tltt lio+l 'I.'-l'r i 1 + Iil-dI
1t11: liinv I> Ifr e frlm 1 ntl> (lt;tl ':l r 111 (li e > +,'** iI :iicn t .1- 1 Ic
exil~lal tIat ion f1, lh rnL :' l'l i"1o t itl l]: :I'+rlt Ilih i I.c lir+:
,., ,r .,ii oii o fI livliridl- r l t rc ci~t.- nn iiitcuriin,',ni l i ^ ;>+, _'<' 111 llr i iriri'...
ol ~ ~lt I li+t ~ '..+lI ++ l M I+i'I~ ] Uttl~ +t \' I+, I++ r(, w
itf con IlL'l Io Ii^ li I' li I' 'li l ''c i il -. w u h i -** 1i
::, 1 11 i i .1 ru ilr d ;l ii >i ic t co il .l' ;tll 10 1; ll;>1 1 t k 1 [ 1 1 i !.
TI huI h m c' s l i r, an ;dll101,n I rc ci lo r I 1 1 1,ol w 11 Z l r I 1cI I 'N I I-it
for ;(( hr'i-t t'wo ,in ,'rtti,,S in! I. o r'eject *~1 *{t~ir ,++rnttion iyl>rid *+ I)'
< w;lsr tll+ v 2ypiK'ar i i [)loiliii liii i tI I)t id',;" I (Ili; I ( i' Iiri Ic I c I I v 1
Dinett ,l +of (I'O''Il!; i< r:lll\+ ('O>ill|)[c<>. It i l~llv lllle0\vliii:+, ;>',,.;1++ V Hti!]0
;,1.,, I-, o r I ;ni i:i)(: lr 1 l iisc l l 1.\ d o 1ol 11ll th 11' 1 j|)'i l, I1' w 1'
su lt I In c Id Il l- ii- r(''>|(> Ii IviIcIxI I It' iU d iH rI( ;i'.>1:rl
clll mi' 1i11' olt'1 l lhiric lo lel~e l I ic v I' I I( t
act(,e of (lo t l -r-t I i,, I I i ltv i \ to; 1) yt v Ix' \\hicli do nol \I'1( l Ih q, +l ro 1i)ii t l:1i; 1011 ol' )a ire i a I;o I--;ln .l e :
tIhe fil't j I' v l'tli'lt i Io l IV II (h)ill ,to -n iII (hIt sco( )Il i {+.' IoI; Iti()II.

PRI1' 11TIV I. CHARACTERS SHOWN i:: REVERSION A' D
RECAPITULATIO: I
1n) d ln'r iiniti\'v (liirnlt crall llt Itlif n itH* i-.< ;t1ijcc'i llx"l o c ii< 'lr
iflr. w h .lii li li vc'' 4 ', C(i m d to lie ii _.wl lt 11: tI'l v oxplvrc lthinl co'l l.to li'+lil
oly1 i1 o0<( +;->io l in :1l1) c ltor^ iOll ittm] of ric't' m hill ,ii thoir iIIIiielticd c i;arcl .'( .
FI ct- -li ow *_, (tle p(Tw i.e!vi)c f ol' {)rinitive i\ '( (liil;la tc! it |)l; i"t! andi1
nii ii sll ; ; 'ti'e (*oilii~ino iil t, .... i -iii/cd al, c t l i tli nytii tw I\\+ o l' illcl 1),
If Il iiwn iII c(ilh d l 't \ t>( Iiori nnilt I roca't liit lt liA inI. lelI l)cIhi iavIo of
[ChIr. IN|;;


1, 11 1. 1 1 ti






A PRIMITIVE CHARACTER IN COTTON HYBRIDS.


our cotton hybrids seems to show that the relation between these
phenonmeIa is very intimate, and that one may pass into the other
:Is a result of hybridization.
Ieversion is the reappearance of a character which has been trans-
mit ted in latent form-that is. without !bei I brought into expression
in the plarelnt ,'I|'I lit(on or in a previous. series of generations.
IReca pit elation rmay be described as the following over of the ances-
tral paths of descent in each generation. Studies of the embryology
of the higher vertebrates have shown that many primitive features
are brought into temporary expression in the course of development
of each individual. Mamnimalian embryos still show gill clefts and
rudiments of othlier ancestral features which have not -erved as adult
(ch1a rPcters for many geologic g.
IReversion and recapitulation have no limits in years or in numbers
Jf geler:lt ions. They give us a vivid indication of tlie all .-..lr:1, i',g.
all-endnring power of transmission. Darwin h1as aptly a's-ociated
lthe permanence of latent characters within the persistence (of rudi-
mentary organs:
Th'I'liere is no more inherent improbability inll each domestic pig, during a thou-
sand generations, retainiing the(- cpacity and tendency to develop great tusks
indeWr filiting conditions, than in the yomng calf having retained for an indefinite
nm ul"er of generations rudimeinitary incisor teeth, which never protrude 1.r.'ii.'h
the gums.'
In this. as in many other 1:,--:1ges. Darwin irc',,gnizes a distinction
Vlwhiic many subsequent writers have overlooked, perhaps because
1no definitely contraAted terms were used to define it. The distinc-
tion is between (1) the process of transmission which convcys to
successive generations of organisms the "capacity andl tendency to
reprolduce and tra nsmit the characters of their parents an d ancestors,
and(1 (2) the process of expression, by which characters are actually
developed'" or worked out in visible form. These two 1proc'-.--,
I ralsmiission and expression, give us the facts commonly known as
Sheredity."
lRecapitulation may be described as a temporary or partial exprr:--
sioln of a primitive cliaracter, while reversion is the expression of a
character whiich is usuiallv transmitted in latent form without conili.ug
into expression at all. Recapitulation llay never be visibly com-
p('let: many ancestral cliracters are not brought into expression, but
lIe power of such characters to reappear shliows that they continue
(o be trlansmiittled. The "ccapacity and tendency" remain in the
protoplaslmi. even when no visible tissues are formed. The many
ifflereint reversions shown by members of tlie same stock indicate
thlat all tlie a ancestral characters are probably transmiitted and cun-

D )arwin, i hI.11l -. Varialion of Aiiimnals :11(nnd IP lts under D)omestication,
<' l (iip r 13.
(Cir, IS)




A I'IM IITIVI (i IIllA\l 1';l N IN ( II H tUi1l)DS.


Ztimi to Ibe Wapable of rel'w ininll, exl p ess-;ion lht .s( me f i1ili] ll combh

l:tioi i, ter f ie s t o e iln. o m*al (mumss ir i lli, IIf (1 ll



X.,it ion a nd ra sfer to new l i) li tl -II' are llit amot I ;Viiilith 4xi( ii.'o


co1 fo diIt character.ion.







REAPPEARANCE OF GREEN FUZZ IN COTTON" HYI;I.ID',-
o 'lier i' ,cl e of 40 "vel m eIt. ftlhu l ;l' I n- n individ altt i)ini orhi
hnir d is ho ime n, a- li were, ()oi {iiiulnt'l.al all- % -i al Ii \ v ;
Th.o1iidi only the ch sn charactersI artc bI'oM *_itin o pr->ioi, tllt,








rii' "'_', f t ;ia nsiiii.tlxr (i t ii a'iiiti- it in lii. llla ndl i ii:) rtl Eachl' ;l I l a m


mlelt ir.t I. -*h l t limiml- (i n;ihliii =l, orii rcb -rc- t,'ion hi' ows th)ilat ]i( h


;' 1tli1 I v' tlduto ti Iolliht I 'i roh ttl' ii''')lI '' t1llb iN ')ai ''i s and x ii 'r'
recent ;uu.Tstov r: int limled r iiormol meoiid ioun- of dc,(,cn i!), ,, i- a
whid lilw~tv of MlOic. lIndividiial diver,ity i, ixri^eii -iiowNv .
even when 01 'o.ii- oAy lothie\.;in anw mn'v ryv dvirv o, l)iid llun e l~aw m>
conditions.

REAPPEARANCE Or GREEN FUZZ IN COTTON HYJ.IDriD

llemulsion is often reckoned a~s a Ion, owl excel)! ioal p~enomenlon.
not to l)e under too fo the standpoinht of normal filleritantce;, bill
IN. fact is that inany reversions are as deinniv and mil fbor as anyv








oe' poc s,,es of ( ocent. Tlus there ari mo 'ara'llli lh hi 'h in I w )it I
I Chid ewo een te alli cotton ol l l"indl ivla ; i t,. I N h- lA id
(X', r |i! ian eotton ;I-' in com're( ine> t llirii in' wier l,() ho n in r Ow 1 Y
A mize of I ,e slee S ha de ili n -.,e dnsoe (coa(t Of bl11ish 2hiie fUz/ z Nvill \l I
thle seIds are covered ni. derni th lIIIe ( long. whi1 !in(. Tlvha( M rma '
ters renlder hlle seedIk l (lf t hy labrids abruptlynl diffreit \( romi lIo-('
of tlhe p);men type".
The reoorval of thl,-lit leaver (lte Witse hf thed is of the Wealli otton ov-
ered with a, dense -hite l(i, I/, wiI ( lithe co( L olf th e sellei-Idlf. w;id
E-gyptian ot'tons' are lack and naked. Thms the g-reen fuzz of 11w
lItl iid seed is not a blend or otlher ombiathiont olf lhe parental cAm-
ncleis. thon-lh it may lbe viewed as ;4 omipromnise beqjwejn 1he paren1-
tal conditions if considered in relation to odlie f'acts' of me\er~-ion
awl rerupol, lat, ion. O]l of *e fI1zz are Mo i nd iln manV dif,
feent, t_ h. or rotton, icloding wlo,' whicic are native in tlhe Old
World, ;Iid es-pecially in wildor "njimproVedl variotie.'. Thu, it
11 iil dll'represents an ancrsiral condithmi 'Owl whiicl lW hl olr lIN
parental types have di i_* --. No wild cotton.- with, while funzz seelin
uo he known. but nmo~ olf tlhe WNak-mlode co"ns hiave a -mall tuft
of w-' i. (w brown Val. at the basv olf tlhe seed. A Guiatenmalan cot
Ion of tlie Se-sa d sries lias tlIe lowevr half of (hev nml coated
withi _=i, i, IN/. 10i Wit. berlin vonithm" to llhe uppjer half. wliich
lhas I",o I'Axz.
''( illii H Vjy'i l I '.illh-l ill .ss.
}lhir;>n of l)I'ltl IT" d"try, I S. lHI, ul. f i '. ,i nn'r, |>. :;'.
I t'r. 1s)






\ PRIMITIVE CHARACTER IN COTTON HYBRIDS.


'The reappearance of the '2,.ii fuzz in these hybrids need not be
i-,i,,r, .1I as a turning back from the characters of the parent
va'ieties, ats (lie word reversion seems to imply. These hybrids do
]iot follow either of the parental routes of development, )but com-
promise o()n ta primitive character which appears to represent common
ancestridl: ground. A stage of developmentt which is quickly passed
) v or elitirelyv latent in thle parent varieties remains as a definitely
expresse(I clihmracter of the hlbrids. Abortive seeds are often folllid
with gren futizz, ev(n when normlly imattired see ds in the same
lock 'ave \white fluzz. This reversionls c:11a Ie viewed as 1111il, in-
of arrested d( elo'.', ,, failures to pass beyond -I i-', marked by
p~rhifi i\ ('h:**rdamters.

DIT *'_-.':.i -. BETWEEN FIT.-"f AND FLCOND GENERATIONS.
ThIe ircalli to expression of the ance-tr 'l I ftzz character is not
permnlcnt. Thlie next generation slios a wide diversity of comibina-
tionls and I intergr:ta(lationls betweenn the characters of tlie parent t,\ ie-,
buti there is no slhtli failure to attainl thIe parental charai'ters as in the
lirst ii It ion. thoilgh ilhe greenl color somlitimles remains in the
secondd a111( even in lhie third geinerati o. Why an ancestral character
should so) r egularly.\ ppiearl in the first generation and almost as '"_!-
larly di:appear H llie second is not easily understood until we remem-
ber thatt lhe second genera iion is thie first that represents a completion
of tlie coijijugation begun by the original germ cells."
The iir.t goeleration is forlimed d hring thlie preliminary .t,.i ,. of
cotlijugationI, so that tlie temporary expression of ani ancestral char-
acter in the first generation 1miav not be essentially different from
other phenomena of recapitulation in which temporary expression of
characters takes place. Instead of an intermediate a, ,r._12 between
the divergent parental characters or the dominance of one over the
other, the gr.,ii fuzz may represent a third method of aljii-.ting
lhe parental differences, by coimprollising upon a CotIiuon ancestral
character.
If we think of tlhe green fuzz is in tlie nature of a chemical conm-
binmiation of the parental characters, its failure to become "fixed"
appears very imysteriolus; bulit when we associate it with the phlie-
nomiena of reversioni antd recapitulation it is easy to understand that
tlie disappearance of thlie irci, ji in the second generation accords with
he very frequent result that the second generation of a hybrid dinIers
from tlie first. An intermediate and nearly uniform first generation
often produces an extremely diversified second generation.
The exl)erimients of .Mveielc and his successors have made us
familiar with the fact that parental characters which are -iippresc
"Cook, 0. F.. nltd Swiighl WV. T. E'volc tiofn of Coiihlihr SIr0ct.re. bulletin
81, I (.ir..i t of I'l-li ltishis~rl'. 1'. S. Depl. of A1905ultiirc, 1 i.
[( Cit, 1 ]






\ 'iMi' Tiv\ In \ u' m icmu i\ (1'orn4


in the 0-i 1 it 14





I i ; 'A ll 4It '> I :"

\*' lr l lOl4 1 I. 1 i4 1 14 1,f 14>


: 1'kc 111 ;t4 i ; ii I i !i n 11 :

'Ilu ilill 1. 1 4. I I ; i *;'i 'r '



of lie .Iecwr ^*icri x1 i lit 4
!IIIj iv \ l h iil!< / ; i
lisl~ll sl m i \ lir i li (* ltro


Ix i~ I'' ii 1
4 *~~~ Lxii j~1
Vt' ~, .41 41


I 44 1 4 1 U 1 l I;


1 W i : ,i )I I *

1 ~ ~ 1 [);1r4 'lr


Iii I
144\\ 44 \ 4
1441


1i 1 2' 1 l., C:l


xPSSION OF CHARACTr. I, 1'
GENERATIONS.


th41l t4 x((> l4d 114 r Ii,' follow d '14 (li1m iii'fim : iii K, -il ,ni!tl h1ii !r' (w o t ;l Ito cl
(r period) (f ;,lut.-li u(I i (,1 f ll4' 11l4 !:' i r la+ii1ii wVi 1' 1, II I lil
0xr141 h2' oI11 tin 11hrl 1A i ntr:-. a)n1 1 djiit41 4l t i tw oI 41l liii (' m iqi

\icnAii o1 f K -I ico ter W;o n 'Id 4IMM Ui (li
.l ,,, :111- 1 i 1 the all44f h 110 1Ad, a o It1, and l.(l1 <>4 4iCn
two 0 1' W M'II A -,'cotI ; l iiicn( is -uu !, ()IJI'";I'>OI i-.
bo'nfurhitc I ln tl ) f 'u-io of ( I(+1 111" 1 ti4' lii.l' ri:;l of (lit ell'I t (nnlp :si>
sis) 1I 4'or, 11tli I'fin .lti l (t' l'i 11111 1 r a .li 4'l 11i 4 '1 { to tl.i. p 'c
onld a, i, .t lon i. TI' p w ;l,]. in, A.l ;iad "miKe n ti: hp()iijiin':iiloi ol0 Whic
erm t'cell f 'l imi-' ant u(l ti lll lv > iW pr foun li than l 'o4 4 aicc- '{1titiids1'l
when omnJ _-,t oiml i:s -inpleted.
I'lT, t 4'- ;f{rid ItiuI{il ],: 1 tll' K1 111C 1 1 '1i '1 1 4h'tc4111 n:IJ tih d UN-
pression (of (,!i :';.{((>r- in A ,)< lir-t L At;(') ic >: tl: il ,i nhu + (I4e m il
; ''_ iti ln 1' . sI a s. TI lh e fi t11 ia ( In e o nd; .il :1 l l-t' 4 4t 1" iV !i ,n v I'
until thie second ge'n ralioi, whiil i+ iln "'i" it t j!", 1cr",hW -P
&, form"d a;ft<'r ,on -',tin ]i ha-s lwv,. rnlhld 1),; i A i[i.sk '1'lic
s-eo '_', ;,,' Co .tioi often sho s ;a verv itd often ;a widelv varbi d series. Indiviid, l n i ,-,i ",rs of this i,
eriti{ion freyiew ly v iff{,r ;ts nnih fr? ni e'icli othKir :m-Q a ,rM ni t{,
{t;ittn(a; types-.
If chtnian tt,-, caoil~ined liM e other M OM ii'scl otr (ht i +i' l snl}s(;tii<'(",
We IIii_'1t Hi xibct u n that liJoe 6._viitc nt would I't hers h l* yIrido s of the saiie pli:n ii(;ie tqy he mdlhvssly diver+-,.
[Onir IS)


SE .CON;)






A PRIMITIVE CHARACTER IN COTTON HYBRIDS.


'i I, facts of reversion and recapitulation enable us to look upon tlihese
diversities of hybrids as corresp)ondiig to the normal diversities of
descent of the parental groups intensified by the recall to expression
of ancestral peculiarities, such as the green fuzz of the cotton hybrids.
If the green-fuzz character behaved in a truly iii.I.-i in manner
half of tlie second generation would have green seeds. The theory of
",..,,:elism holds that characters are transmitted as separate "units"
ald haflint the units whichll represent definitely (cotrasted parental
characters pass into separate germ cells at the end of the first genera-
tion. Thus the germ cells formed by the green-seeded first genera-
t ion would carry either the black-seeded ._.' I i i character or the
wliite-seeded Kekchi character. Ilalf of the gCrm'u cells would con-
jigte with others of their own kind and half would lind mates of the
oppositie kind. T',- contrasted pairs would give rise to green-seeded
plants, while the other Ihlf of the second generation would be equally
divided between white seeds and black ;eeds.
Tlie general di-:, ij,,. i'ance of the ;,'v.ei seeds in the second genera-
tiol1 indicates that the g'e'rm cells which produce this generation do
ot IhaIve tlhe same expression relations as tlio-e which produced the
ir-( generation, for there is not tile same tendency to recall the grii
fuzz into expression. )Developmnent no longer halts at this earlier
stage, but bri',.- wack tihe, white fuzz andl thle ,mooth seeds of the
parvilt types a1d muily i ntitrmedi te conditions. The parental charac-
tes' are ; oi only 11niite'd with each other in varying combinations, b)ut
also() in combil ition \vithi occasional traces of the green fuzz or of
Irown futizz, a ci:irai(er which also ppel1'rs in primitive types of
co (tnl. Trac-s of greeln or b)owni fiuzz umy eiven arrive without
hybridization, i time in the IUnilted Stats, or when o0r 1 1)lalI varieties are t., ,'ii in
new localities. ExXposure (o 11elw conditions disturbs lIhc usial course
of developmentt and briings many .it-mt ,diversitie,,s into expression,
Sien (I e same diversitiies that are found ami,.. the hybrids.
1)i !h.. 1, crosses between thle am >c sto('ck may show iii i' rent de-
gr(es of exprsio n 'Xof thlie : ..'!I character. Sometimes it does not
ail)pear in lie O fis't grederati ol and sometimes it L:,I in a lir,
proportionu of tihe second generation. T!,, strongest t,.iil'iu.yV to
retain lthe gr('en fuzz has ll'ee notic(l inll a hybrid which had the
J.l :imovitcli 1._. ltian ,cott(o for tile female parent and the Kekchi
cotton for tle male parent. In one planting of thirty second-.,'ii'-r -
iou individuals raised from a grei(en-seeded plant of the first genera-
lion, tweintly show at least a trace o(f green in the fuzz, five have tile
seeds nearlyy smooth, and five others have ( hiem densely covered with
whit( fczz. \Xiuui','! the twenty reckonedl a havis g gr,., i seeds there
are maniv gradations in the color as well as in the amount of fuzz
orn thie saee.
!Cir. ISI




A vI 1t rivI (C II ;\N ( l l I\ N 1 -1T N "\ IIYB I I>.


EXPRESSIO'. OF CHARACTERS DETERMINED BY ADJUSTMENTS.

It is not necessary fo suppose))O thi tha e nltr ort the fiparental rhair
actors in the secomml operation orl the c(tmon hynlrisl is caused by i
en'r rwevesal or MIniing of hlie illtfrllI aidjusAtm lelts N hili led to,
th for ion tfriihe O A een s-eeSl- as hlie Itheor of Ienilelin a-
sillins. "1 I, lro 1abili{. is rather that tlhe i)areiattd eliaraces rietlurn
because rl' uher ;mHl nioreN eoplllete mju-lili oll t\e lo ee rieahedl.
Even from the slanlolint of .lendelism it hi;is to be i, ,'li/ed for
the first _', i itlion thai tle explresion m relations o>f the chara'ters arcl
determuine(i by aldjiustment.
Thlere is n1 r season: l| believe tlhat eitlerol' tle wi v sells which haWe
formed o(e of the .Teen-seeded hl)rids was id lju-ledl to lriin tihe
1 i-seed clh;xra'ter into exp)resion. The prein-see climraeter
would have eumoiluo d to remain in ateyalnec if either of ihe ;. ", cells
w'hih 2,, jise to )a yi n,-seedol hylrid hlad conj ,.: i, Oiii a part.
iier of its owni khind. Ihit after the unju'ation lbeCan, llne teUndIenies
oft expression wer., changed and ttle g*rn-mieehc clharacltr at)l)eardt.
LUnde'r ihe 16imor of MA id'li-n (wo uill're i'it ;-i sn1])1llions a;o used1
in atlleijl "iL- to oxl'\ itin the two clhinges o 'cliaractler-, aw\ v 'roni t le
liarents au nl l tl b l)air< -_ ,in. It lihas to lw, co,. W-iil l tl h the i ar-
ncters of lthe ]I -I -encratihn are dhterinedil as- slatedbl. a rh.a adji -
nliit of thie interninal rlation- whlich "- ovein thle 'X\pr---o' f the
ehiaracters. INt win tlhL e end of (hol thleon 4 lio is racl ched ;lII( Iew,\
'v I .i cells are to w)e formed Mflv limui a-n s nni- thiai lthe e'plWI"--sioll
relations of (-he wew (A nells ardve d rniedl- in another 1and verv diit'Ireil
way, by th(e v, am,- mlon oh ihe "unlits" oh the f !tocontratd plarl'eltal
characters it) dis:inc( g'orn] cells.
ThIr aissm [t)lt io(M-I of Mldhlis that thie' chIlaracters- are r,'prIeJ n iledl
by units and hal tlhat s are aireeatel =d l an +re t IanslnititNI In- difi
ferent 'el'lit ,els, I& ol t eiiiIcelis-slI uiir -"1I soo as we ( Siderl that l't.
expression r1lation- of gerni cells may In determine lly Adjstntivne.
The fact llil t(le 1 )xpres-ion relations ol f I 'em c'ell- are cIapale of
l)eing readjiustel after onin'I ,ti, o ll should 1ie rolliehi as e ,vildehe
thai thle rMilio+ s tlev liaxv' leih'ore onj i,m Ilt a-re also re:ach'ld IN-
aIdjustment rinl r 1tl&a 1 v exclusion. I, f l Amra ors are I()lo b lI of :a re[n)reseitned in Ole g'ern cell- I)v ile rile I )rticlve- Or m iatelrial
"1111nits of v kind, it is- moe in a,'oind "ii, (l e I tis lo tllhink Ol '
hl apro ile`, ;i- +xliant win ,. some pxo-i mtin l. d 'h,,in l. or other rvla
lion amIoi 1- tamjgs'J ,-11- than a-- b'iIrj sc'l:ra otel\ lrai -lmiltle in Oif
felr li t L, :, vclls.
Sn'h facts : ts (lhe realpl)earan.,l oh the green 'll ZZ ill thle firs-t .2. 11. ra
tion of these cotton hylrids show that ile ri uastiliden of 'expre-silo
relatioms in the first generation is not (,oli& A to the parental char
c blerst, )ll y inv olive e te r al tl' er I" extire-iom of plrinitive lariic-
[I ir. 1S




\ PRIMITIVE ( I'IAiAC'I 1. IN COTTONI N HIiYIi)D .


(ter- transilted in latenIII t frm fi. ii remote ances-tor. It is one of
SiXi;HY iidicationtsl (hat the clhangeI- of expre -ion relatio ns which have
o Ia askrid to :djust tmenlt are (jquilte a i'.' .it Aas those which ..1.i-
'jli' has>, sought to explain b tlhe theory of' cliracter units" and
, f +heir ;. _...... tion in pure g:erm co Is.
Si(T \:o n l e 'dlim lihave ", ot con l ( C tin' idea o a i.tra-
,I Of cIarau: i r it' 0, wilh "lh i)ro .-o f ''1i 'Ire are titled. hIe u Licint Io -r Wcells are formed lw
>i vidi.. w oi tler cell 1' s led, lo I 'Ie ,. _.' -',- n that .a epara-
i1 f 1i HIrI'2 I i* i 1 t 1i- when tlisi "s u IXivi-
t-!( ;k(c.- j')ili('(i Two f itih i-erm 'Iil 00li] {oitaik tic unit "?
j)1'rccitir on' ( 1of sii' ce, itrvial '5- 1 i(n'a .'s :aild two other germ
liI: (ihe inmil of lfli other clhriir. T'iLi would give equal nnum-
I', of Ii crn' el:oi. of (lIh ( \o kin dsX which hIe thorY of M"i I i -i
.,,(,<. N( ve (h(-leh. it it h) -h, for (lis eq ality to be reached
ill a llnolth r l(o re pir 'ic:l way. T hv vm.l'rs of L.. 11,1 ellss i.',l. 1''!
to( expreo- 1(l c'oluI't-leo ('liar:ifir wNill be .p'.d if cji;l nm" I ber
of tihe mo''I e ellI b)eome adIjuted id (the' (wo Vays before subdi-
vision i)( >-4e 11 iohl'r cefll hmei Io, of (lie same kind iWsiead of b.;".2 of two
kind(Is. This view i u more ,]]ro' icnl be(canec it does no require ,-Is
(o suppose (h'Il the motlhr 'el!is divide into umnequal parts in forminlini
(1eri eells. In vicev of (ihe i'r,,tjie'Y of I (ie' pl0lenoene1a of rever-
-ii 'a11d recapitilaliolii 1 is i Ii ea-s-i (o s-upposeo that both of the
'-ontrasted chlaracter- arc ,ra,.-,itted. h.'.nh onlly one comes into
elxpresmion, th.1,n to l)eli(,ve that (1 ere is a: sepIarate Iran.] mission of
character units in dif',erenit 2n' cells.

SIGNTYICANCE OF PRII.IITIVE CHARACTERS IN BREEDING.
IBree(lers will appreciate the practical importance of the fact that
such a character as the -reeni fuzz of cotlon is n( leot ssarily pi'n'n
rent, even hloilhll it mav be slho)wv) byI all the miemlbers of the first
veneration o)f aI hIbrid. As soon -is we know that such a character
is likely to di>allppear we recognize the need (of carrving, our hybrid-i
over to the Second and third generations before undertaking to make
final deteerminations of their merits.
Even I,.'i,, thle cotton hybrid-s it lias to be considered that other
andi more important characters may v be al'telted by the same prin-
ciples as the green fuzz. In the first general ioll all the hybrids be-
tween the central l A.erica types of (cotton :and ouir improved Upland
varieties prodlicedl slhiorter lint than either of (tlie parents. If the
short lint hIad been looked upon as a permanent char,'ic'r, such hy-
brids would have been rejected as of no value in comparison with
(he parent varieties. Nevertheless, a series of these hybrids is !H.iii.
retained in order (to learn whether the short lint will not behave like
ICir Il'








a primitivv (lI rll: ct ('r ; Iu p 1 lit I 'III
Indeed, lhus-.c' 'rm ;:tilrc ( Ine hi~ki g- ,',. J. ,1" JiVTTl


lint I t[ illi iipp t inI Iho 6Il'M 1 , I!(' r l H)H.

SUS' M AIAY.


flzz inh ( h i 1- I r- n ;! 12i\) j it"i 'I x ii' i t
in elllner ol' ( In- p)'tu'ritl;t \ v lri 'l ic '- tl -) ;lFi it i" I

I I~ l';l ( <) 0, l)> i o l t k in11Ill. ~~


rel~iilcd.
I Ilk I IkF w I S 1 Ih~~ik II~iIIIU~

f:!1 i' I z 1: v 1 t

e'tili iI Il I lI ca t 11:11 t b t I ho rt II~


n'cip~ihi 10 1 1.; l


* l:; k' I<'\" 11 1 ( *i']

;' ( i i *i~i r cl'' t o


< txpresion iw tli, il l .I t'. lltnkII I e 1s c i l i' ii i 1 .0_ 1 ll
aroce s ot III i klio ((ili i e rIiiltl I Io I i -1 I '





)C 1 :II I ThA)1'lg 1I well Ik lI I~Ik Ibi-r c IN kl~ ~
('titcm visilble in t1 lic + ** 'd i'!;iiOii. w ln' <5i ct> t : i);;.' l i tl (* Ii i '(>



It('I)h ou;t in I \ 1, 1 )111 t i l l io l Ian jl . Id' Il'lk. l II' l 1II: It I ib (h ):',
Thi e il" first aI( -,-c II ^(l litiitiit- If l! ! wl- t't)l lt 1(1t l di v roll I
-li "jos o'f thie pl i)' ,1'. i 'f co il,,,m';n innl it i- poss -ible' t(o l!iuUtr-l;/iH t'i !<


wi1 i(' t Il rn.li li'bh llI l k'ullt ll P ,l( of rt lli( hl 11N 110 ) bt k s (lk i I.-/ l
Th0c tnic; ticsil |)<)ii~t i s tlit -nlch i/ d lpar ures fromlt Itho l 'i>;irtilil clar-
ac'tPIs iln t(ho frst .**'. ', 'at li en of h vly rid lmaV nIot I'('inl;/iii (o di'trnWcl
f tromnthevahiH.of lalt' -, ,ii1-. ll 1tn'idl i- w li (Icsc i ii1r.
aitlc prin it iv I I I I I I ve Io'I irno oxj)rI'tii's I 1IIIo II 1 ) mn-i cx 1" ;t l
lea I two .-, r, ratioII s )I t' o e r -election ()it I ca eI r cc ivec lv a!i! ed. Tho
clIiiii s i t l ) (e ir/t I'IItoiiO I da 1o iord an 11k I 'a Il
indic-:tion r.-.rdii ii VI I cliinlctvrs of tlhe later ITXerIliotnI.

Approved
,JA MES WIILSO;N,
,<'(' ,c ," of A .
W ASHINGT(ON. 1) ()c..0 [Cir, fIS


A 1'U.M 'l VK C Al;\'I IS IN O I ON I I V) I; 1.


('1 1 J ". :! i




U iIvtKI l y OF FLORIDA
' 1 2 I 6 I III I II II U
3 1262 08928 9523