A CYTOGENETIC INVESTIGATION OF SEX EXPRESSION
IN SPINACIA

By
WILLIAM PUTNAM BE MIS

A THESIS
S u b m itted to the School of G raduate Studies of M ichigan
State College of A g ric u ltu re and A pplied Science
in p a r tia l fu lfillm e n t of the re q u ire m e n ts
fo r the d eg ree of

DOCTOR OF PHILOSOPHY

D e p a rtm e n t of B otany and P la n t P athology,
and D ep a rtm e n t of H o rtic u ltu re
1952

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ACKNOW LEDGM ENTS

T his study of the p ro b le m of sex in h e rita n c e in S pinacia
h as b een m ade p o s s ib le thro u g h the jo in t c o o p eratio n of the D e­
p a r tm e n t of B otany and P la n t P athology (D octor W. B. D rew ,
H ead), and the D e p a rtm e n t of H o rtic u ltu re (D octor H. B. Tukey,
H ead).
The au th o r e x p r e s s e s h is thanks to th e se d e p a rtm e n ts
f o r the s e r v ic e s and f a c ilitie s re n d e re d to him .

He e x p re s s e s

h is thanks to the m e m b e rs of h is guidance co m m ittee, and is
e s p e c ia lly in d eb ted to D octor G. B. W ilson, D ep artm en t of
B otany (c o -c h a irm a n ), fo r h is p e rs o n a l s e rv ic e s and advice
co n cern in g the cy to lo g ical and genetic stu d ie s.

The au th o r also

e x p r e s s e s h is g ra titu d e to D octor R. L. C a ro lu s, D ep artm en t of
H o rtic u ltu re (c o -c h a irm a n ), and D octor A. I. Isb it, D ep artm en t
of H o rtic u ltu re , f o r th e ir advice co ncerning the fie ld plan tin g s
u se d in th is study.
The au th o r also acknow ledges M r. P h ilip C olem an, e x ­
p e rim e n t sta tio n p h o to g ra p h e r, fo r the p h o to m ic ro g ra p h s p r e ­
se n te d in th is p a p e r.

A CYTOGENETIC INVESTIGATION OF SEX EXPRESSION
IN SPINACIA

By
W illiam P u tn a m B em is

AN ABSTRACT
S ubm itted to the School of G rad u ate Studies of M ichigan
State C ollege of A g ric u ltu re and A pplied Science
in p a r ti a l fu lfillm e n t of the re q u ire m e n ts
fo r the d eg ree of

DOCTOR OF PHILOSOPHY

D e p a rtm e n t of B otany and P la n t P athology,
and D e p a rtm e n t of H o rtic u ltu re

Y ear

App r o v e d____ ' „

^<7

/t \

1952

_______________________________________

1
WILLIAM PUTNAM BEMIS

ABSTRACT

Sex e x p re s s io n in the a n g io sp e rm s, along w ith s e v e ra l
cytogenetic: ex p lan atio n s of s e x in h e rita n c e in c e r ta in p la n ts
and a n im a ls , and the effe c t of e n v iro n m en t a re c o n s id e re d in
the re v ie w of the g e n e ra l p ro b le m of sex e x p re s s io n and sex
in h e rita n c e .
two p a r ts :

The e x p e rim e n ta l w ork p r e s e n te d is divided into
the cy to lo g ical in v e stig a tio n and the g enetic in v e s ti­

gation.
The cy to lo g ical in v e stig a tio n of S pinacia ole ra c e a L .
c o n s is te d of a study of m e io s is in diploid m a le and in te r s e x
p la n ts , and in te tra p lo id in te r sex p la n ts .

No evidence of a

h e te ro m o rp h ic p a ir of c h ro m o so m e s w as d e tected .

The c h ro m o ­

so m al co n fig u ratio n s of the diploid m ale w ere the sam e as those
of the in te r s e x p la n ts; how ever, th e re a p p e a re d to be a d if f e r ­
ence betw een two in te r s e x lin e s .

One in te r s e x line contained

two n u c le o la r ch ro m o so m e p a i r s , as did the m ale, and the
o th e r in te r s e x lin e con tain ed only one n u c le o la r ch ro m o so m e
p a ir.

The te tra p lo id m a te r ia l exam ined in d icate d the p re s e n c e

of a t l e a s t two tr iv a le n ts a t M etaphase I.

M eio sis was o th e r ­

w ise r e g u la r up to te tr a d fo rm a tio n , w here it b ecam e ab n o rm a l

2
WILLIAM PUTNAM BEMIS

ABSTRACT

by p ro d u cin g m a n y -c e lle d 1't e t r a d s M o r p o ly ad s.
p ro d u c e d fro m

The p o llen

such polyads w as i r r e g u l a r .

The g en etic in v e stig a tio n c o n s is te d of fo u r g e n e ra tio n s
of b re e d in g S_. o le ra c e a L ., fro m w hich a sch em e f o r se x in ­
h e rita n c e w as d ev ised .

P la n t types and flo w er types w ere d e ­

s c rib e d in o r d e r to obtain a sy ste m of c la s s ific a tio n th a t would
be su ita b le fo r g en etic r a tio s .

The genetic schem e d ev ised

c o n s is te d of the in te ra c tio n of an X -and-Y ch ro m o so m e m e c h ­
a n is m and two co m pu lsion link ed g en es, w ith a v e ry low c r o s s ­
o v e r valu e, w hich w ere independent of the X and Y c h ro m o ­
so m e s .

T hese two linked genes w ere equal in th e ir s e x - e x p r e s s ­

ing c a p a c ity b u t w ere opposite in e x p re s s in g sex type.

A YY

type of in dividu al was c o n s id e re d to be v iab le.
The ab o v e-m en tio n ed schem e was ad apted to f it the c o n ­
ditions of se x in h e rita n c e found to e x ist in S p in acia; n am ely ,
the m ain ten an ce of a 1:1 sex ra tio , the p ro d u ctio n of in te r s e x
p la n ts , in te r s e x p la n ts w hich a re p u re b re e d in g fo r the in te r s e x
condition, in te r sex p la n ts w hich s e g re g a te into (a) in te r se x e s and
m a le s , (b) in te r s e x e s and fe m a le s , (c) in te r s e x e s and m a le s and
fe m a le s .

TA B LE O F CONTENTS

P age
IN T R O D U C T IO N ............................................................................................

1

GENERAL REVIEW OF THE PROBLEM OF
SEX EXPRESSION
.....................................................................................

3

Sex E x p re s s io n in the A n g io sp erm s
E n v iro n m en t as a F a c to r

...................................

........................................................

C ytogenetic In te rp re ta tio n s of Sex E x p re s s io n

. . . .

CYTOLOGICAL INVESTIGATIONS OF SEX
EXPRESSION IN SPINACIA ................................................................
D iploids

............................................................................

3
11
14

23
23

R eview of l i t e r a t u r e ...................................................................

23

............................................................

24

M eiotic o b s e r v a t i o n s ...................................................................

26

M a te ria ls and m ethods

T e tra p lo id s

...............................................................................................

29

R eview of l i t e r a t u r e ...................................................................

29

............................................................

29

M eiotic o b s e r v a t i o n s ...................................................................

31

D i s c u s s i o n ...................................................................................................

35

G ENETIC INVESTIGATIONS OF SEX
EXPRESSION IN SPINACIA ................................................................

42

M a te ria ls and m ethods

P ag e
R eview of L ite r a tu r e

.......................................................................

E n v iro n m e n t as a F a c to r

............................................................

44

...................................................................

46

.......................................................................

48

........................................................................................

50

M a te ria ls and M ethods
G enetic O b se rv a tio n s
P la n t types

42

F lo w e r typ es

........................

G enetic E x planation

..........................................................................

D i s c u s s i o n .........................................................................
S U M M A R Y ..........................................................................................................
C ytological Study

.........................................................................

G enetic S t u d y ...................................

55
59
82
84
84
84

B IB L IO G R A P H Y ...........................................................................................

86

A PPENDIX

91

......................................................................................................

L IS T O F T A B L E S

TABLE
I.

P age
............................................

16

F re q u e n c y of C ells p e r MT e tr a d 11 fo r
Two T e t r a p l o i d s ...................................................................

33

Sex E x p re s s io n of Two V a rie tie s of
Spinach . . .....................................................................................

47

IV.

P u r e - b r e e d in g In te rs e x T y p e .....................................

70

V.

Selfed I n te r s e x S egregating into F e m a le s
and In te r s e x e s .......................................................................

71

Selfed In te r s e x S eg regating into M ales
and In te r s e x e s ......................................................................

73

Selfed In te rs e x S egreg atin g into M ales,
I n te rs e x e s , and F e m a l e s ..............................................

77

II.

III.

VI.

VII.

Sex In dices in D ro so p h ila

VIII.

P la n tin g

P la n ,

W inter, 1950-51

100

IX.

P la n tin g

P la n ,

S pring, 1 9 5 1 .......................................

101

X.

P la n tin g

P la n ,

W inter, 1951-52

102

XI.

P la n tin g

P la n ,

S pring, 1952

103

.......................................

XII.

D ata

fro m W inter,

1950-51, P lan tin g

................

107

XIII.

D ata

fro m Spring, 1951a P l a n t i n g .............................

10 8

XIV.

D ata

fro m W inter,

1951-52, P lan tin g

................

109

XV.

D ata

fro m the Spring, 1952,P lan tin g

..................

110

vi
TABLE
XVI.

Page
D ata fro m S pring, 1950, T estin g Spacing
and D ate of P la n tin g on the Sex E x p r e s ­
sio n of Spinach
....................................................................

118

L IS T O F F I G U R E S

FIGURE

P age

A.

K ary otyp e of S pinacia o le ra c e a

L ................................

27

B.

F lo w e r T ypes

............................................................................

56

C.

D ia g ra m a tic Schem e fo r
the G enetic
E xp lan atio n fo r Sex In h eritan ce in
S pinacia
........................................................

61

L IST O F P L A T E S

PLA TE
I*
II.
III.

IV.

P ag e
M eio sis in D iploid S pinacia o le ra c e a L ...................

37

M eio sis in T e tra p lo id S pinacia o le ra c e a L.

39

. .

M eiotic C o nfigu rations in Spinacia
o le ra c e a L ............................................................................................
Sex Types in S pinacia o le ra c e a L .......................... .

41
54

INTRODUCTION

The p ro b le m of se x in h e rita n c e in S pinacia o le ra c e a L.
has b een a tta c k e d by u sing tech n iq u es of g e n e tic s and cy to g e­
n e tic s .

G en etics is a r e la tiv e ly new scien c e which has p la c e d

h e re d ity on a m a th e m a tic a l b a s is involving the conception of
the p a r tic u la te n a tu re of in h e rita n c e .

C ytogenetics is the b ra n c h

of sc ie n c e w hich is co n ce rn e d w ith the m e c h a n ism by which
th e s e p a r tic le s a re c a r r i e d fro m c e ll to c e ll, and fro m g e n e r a ­
tio n to g e n e ra tio n .

A c le a r concept of g en etics has b een given

by D arlin g to n (1951).
G enetics began as a study of the re la tio n s of p a re n ts
and o ffsp rin g in sexual rep ro d u ctio n .
It continued by e x a m ­
ining a d e e p e r la y e r of ev en ts, the m ov em ents and a c tiv itie s
of the d e te rm in a n ts re s p o n sib le fo r th e se re la tio n s .
It then
p a s s e d to c o n s id e r u n ic e llu la r and u n im o le c u la r o rg a n ism s
in w hich the d istin c tio n betw een d e te rm in a n t and phenotype
a lm o s t la p s e d and in w hich sexual re p ro d u c tio n e n tire ly
la p s e d only p e rh a p s to re a p p e a r again a t a lo w er le v e l.
G enetic notions then tr a n s f e r r e d to the study of c e ll-lin e a g e s
w ithin o rg a n is m s in w hich developm ent took the p la ce of
h e re d ity and d iffe re n tia tio n took the p la ce of v a ria tio n .
By
th e se sta g e s it w ill be found th a t g en etics h as g ra d u a lly
b ro k e n down the b a r r i e r s betw een the d e p a rtm e n ts of biology.
It has done so by in tro d u cin g those rig o ro u s notions of c o n ­
s ta n t p a r tic le s co n sta n tly d eterm in in g v e rifia b le e ffects w hich
M endel so c le a r ly s e t fo rth n e a rly a h u nd red y e a rs ago.
Now
ind eed in 1950 we m ay claim to have re d is c o v e re d the ele m e n ts
w hich s e g re g a te , and reco m b in e and, above all, d e te rm in e .

2
He f u r th e r ad ds, ’’G en etics re m o v e s the bandage fro m o u r ey es
when we s e t out in p u r s u it of knowledge about livin g th in g s .”
The " b a n d a g e " in the c a se of sex e x p re s s io n in the
a n g io sp e rm s h as b e e n d ifficu lt to re m o v e .

Sex e x p re s s io n is

a c h a r a c te r w hich, in the c a s e s of h e rm a p h ro d itic and in te r s e x
in d iv id u als, is v e ry d ifficu lt to p lace into sp ecified c la s s e s .
T h is, along w ith d ifferin g re s p o n s e s to en v iro n m en t, has m ade
g en etic a n a ly sis of the p ro b le m a d ifficu lt ta sk .

H ow ever, c e r ­

ta in co n clu sio n s have b e e n re a c h e d and a re p re s e n te d in this
p a p e r w hich m ay add evidence to the solution of the g e n e ra l
p ro b le m of sex in h e rita n c e .

GENERAL REVIEW OF THE PROBLEM OF SEX EXPRESSION

Sex E x p re s s io n in the A n g io sp erm s

To w hat ex ten t the dioecious and the m onoecious co m plex es
a r e p r e s e n t in the a n g io sp e rm s has by no m ean s a sim ple a n sw e r.
B efo re th is p ro b le m can be app ro ach ed , it is e s s e n tia l, f i r s t , to
define e x a c tly w hat is m e an t by the dioecious and the m onoecious
co m p lex es.
The follow ing d efin itio n s, w hich a re u sed throughout th is
p a p e r, have been tak en fro m a m a n u s c rip t p re p a r e d by G illy and
W ilson (1952) w hich d e a lt w ith the p ro b le m of sex e x p re s s io n in
the a n g io sp e rm s.
1.

D efinitions ap plicab le to the se x u a lity of flo w e rs:
a.

P e r f e c t flo w er - - A flo w er w hich is m o rp h o lo g ically
b ise x u a l (i.e ., containing both fu nctional an d ro eciu m
and function al gynoecium ).

b.

M orpho logically stam in ate flo w er - - A flo w er c o n ­
tain in g only a functional an d ro eciu m .

c.

F u n ctio n ally sta m in a te flo w er - - A flo w er co n ta in ­
ing a fu nctional an d ro eciu m and a ru d im e n ta ry o r
o th e rw ise nonfunctional gynoecium .

d.

M o rp h o lo g ically p is tilla te flo w e r- - A flo w er c o n ­
tain in g only a fu n ctio n al gynoecium .

e.

F u n c tio n a lly p is tilla te flo w e r- - A flo w er c o n ta in ­
ing a fu n ctio n al gynoecium and ru d im e n ta ry o r
o th e rw ise nonfunctional an d ro eciu m .

D efinitions ap p licab le to the sex u ality of s p e c ie s:
a.

P E R F E C T --S p e c ie s w ith a ll flo w ers on a ll in d i­
v iduals p e rfe c t.

b.

M ON O ECIO US--Species w ith som e flo w e rs on
a ll individ uals m o rp h o lo g ically sta m in a te and
o th e r flo w e rs on a ll individuals m o rp h o lo g ically
p is tilla te .

c.

POLYGAM O-M ONOECIOUS--Species w ith a ll in ­
dividuals b e a rin g th re e kinds of flo w e rs; p e rfe c t,
m o rp h o lo g ically stam in ate and m o rp h o lo g ically
p is tilla te .

d.

ANDRO-M ONOECIOUS--Species w ith all in d iv id ­
u a ls b e a rin g both p e r fe c t and m o rp h o lo g ically
sta m in a te flo w e rs .

e.

GYNO-M ONOECIOUS--Species w ith all individ uals
b e a rin g both p e r f e c t and m o rp h o lo g ically p is tilla te
flo w e rs .

FUNCTIONAL M ON O ECIO U S--Species w ith som e
flo w e rs on all ind iv id u als e ith e r m o rp h o lo g ically
o r fu n ctio n ally sta m in a te and o th e r flo w e rs on
a ll in d ividuals e ith e r m o rp h o lo g ically o r fu n c ­
tio n a lly p is tilla te ; to f it into th is categ o ry , e ith e r
the sta m in a te o r the p is tilla te flo w ers on all in ­
div id u als m u s t be of the fu nctional, r a th e r than
the m o rp h o lo g ical, type.
D IO EC IO U S--Species w ith a ll flo w ers on som e
ind iv iduals m o rp h o lo g ically sta m in a te and all
flo w e rs on the o th e r individuals m o rp h o lo g ically
p is tilla te .
PO LYG A M O -D IOECIO U S--Species w ith som e in ­
dividuals b e a rin g p e r f e c t flo w e rs and e ith e r
m o rp h o lo g ically stam in ate o r m o rp h o lo g ically
p is tilla te flo w e rs and o th e r individuals b e a rin g
flo w e rs of the opposite m o rp h o lo g ical sexual
type (accom panied o r unaccom panied by p e r f e c t
f lo w e rs ).
A ND RO -DIO ECIO US--Species w ith som e in d iv id ­
u als w ith only m o rp h o lo g ically sta m in a te flo w e rs
and o th e r in d ividu als w ith only p e r f e c t flo w e rs.

6
j.

G Y N O -D IO ECIO U S--Species w ith som e in d iv id ­
u a ls w ith only m o rp h o lo g ically p is tilla te flo w e rs
and o th e r in divid uals w ith only p e r f e c t flo w e rs,

k.

FUNCTIONAL D IO EC IO U S--Species w ith all flo w ­
e r s on som e individuals e ith e r m o rp h o lo g ically
o r fu n ctio n ally stam in ate and all flo w e rs on
o th e r in d iv id u als e ith e r m o rp h o lo g ically o r fu n c ­
tio n a lly p is tilla te ; to f it into th is c a te g o ry e ith e r
the sta m in a te o r the p is tilla te flo w ers m u st be
of the fu nctional, r a th e r than the m o rp h o lo g ical,
type.

Some p r e lim in a r y conclusions con cern in g the p ro b le m of
the ex ten t of the dioecious and m onoecious co m plexes in an g io ­
s p e rm s is p r e s e n te d by G illy and W ilson (1952).
F r o m the m o re than ten thousand g e n e ra which c o m p rise
o v e r 150,000 s p e c ie s of the a n g io sp e rm s, th ey in d icate d th a t a t
le a s t 85,148 s p e c ie s com e fro m fa m ilie s w hich co ntain som e s o r t
of d io e c io u sn e ss, and 35,571 sp e c ie s a re fro m the f a m ilie s w hich
co n tain som e tru ly dioecious s p e c ie s.
ecio u s fa m ilie s c o m p ris e 530 s p e c ie s.

The six te en s tr ic tly d io ­

7
The f a m ilie s w hich co ntain m o n o e cio u sn ess of one s o r t
o r a n o th e r c o m p ris e

102,797 s p e c ie s, and those fa m ilie s w hich

co n tain som e tr u ly m onoecious s p e c ie s c o m p rise 22,279 s p e c ie s .
The tw elve s tr ic tly m onoecious fa m ilie s c o m p rise

185 s p e c ie s.

They concluded fro m th e ir in v e stig a tio n s th a t a t le a s t
2,500 to 3,000 s p e c ie s a r e d ioecio us, and 7,000 to 7,500 s p e c ie s
a r e m o n o ecio u s, in the s t r i c t sen se of the definition included in
th is p a p e r.
The p e r f e c t condition (35,479 sp ecie s) d om in ates the
a n g io s p e rm s , bu t the dioecious com plex is by no m ean s a sm a ll
m in o rity .
A nother q u estion w hich a r i s e s co n ce rn s the place of the
d io ecio u s and m onoecious com plexes in the e v o lu tio n ary r e la tio n ­
sh ip s b etw een the ty p e s of sex e x p re s s io n .

F iv e p ro p o se d s y s ­

te m s of the evolution of th e se com plexes a re given.
One, b a s e d upon the sy ste m s of B entham and H ooker
(1862-1883), B e sse y (1919), and H utchinson (1926, 1934), shows
a tre n d fro m the p e r f e c t condition to the m onoecious o r the
d ioecious condition; i.e ., P to M o r D.
Two in te rp r e ta tio n s a r e b a s e d upon the s y ste m of E n g ler
and P r a n tl.

One in te r p r e ta tio n shows a tre n d fro m the dioecious

8
cond itio n to the p e r f e c t condition, e ith e r th ro u g h o r aro u n d the
m onoecious condition; i.e ., D to P d ir e c t, o r thro u g h M.

The

o th e r in te r p r e ta tio n is a tre n d fro m both the dio eciou s and
m o noeciou s to the p e r f e c t condition; i.e ., D and M to P .
To co m p lete the s e r ie s , G illy and W ilson have added
two m o re p o s sib le s y s te m s , one of w hich shows a tr e n d fro m
the m onoecious condition to e ith e r the p e r f e c t o r the dioecious
condition; i.e ., M to P o r D; and an o th er showing a tre n d fro m
the p e r f e c t and dioecious condition to the m onoecious condition;
i.e ., P and D to M.

They conclude th a t the p r e s e n t data a re

sim p ly not adequate fo r any d ecisio n a t th is tim e .

H owever,

th ey a g re e th a t d iffe re n c e s of sex e x p re s s io n in the a n g io sp e rm s
a re c o r r e la te d w ith the genetic co n stitu tio n of the o rg a n is m s , and
the p ro b le m of se x u a lity in the a n g io sp e rm s is , th e re fo re , to a
high d e g re e a gen etic p ro b le m .
F u r th e r evidence fo r the genetic c o n tro l of sex is shown
by stu d ie s on the in h e rita n c e of flo w er types in the C u cu rb itacea e
and in m a iz e .
F ro m a s e r ie s of c r o s s e s and back c r o s s e s in C ucum is
and C itru llu s , R osa (1928) e s ta b lis h e d th a t the d iffe re n tia tio n of
gynoecious and h e rm a p h ro d itic flo w e rs depended upon a single

9
g en etic f a c to r , h e rm a p h ro d itis m being r e c e s s iv e and an d ro m o n o e c io u s n e s s b eing dom inant.
P o o le and G rim b a ll (1939) concluded th a t in C ucum is
m elo the h e rm a p h ro d itic p la n ts d iffe re d fro m m onoecious p la n ts
by two r e c e s s iv e g en es.

A p la n t h etero zy g o u s f o r one p a ir of

gen es is an d ro m o n o ecio u s, and one h etero zy g o u s f o r the o th e r
p a i r is gynom onoecious.
Jo n es (1934) developed dioecious m a ize and p ro p a g a te d
it th ro u g h fo u r g e n e ra tio n s .

Two c la s s e s of s e x -d e te rm in in g

g a m e te s w e re p ro d u ced by the m ale p la n ts; the fem a le p la n ts
w e re m o n o g am etic.

Double r e c e s s iv e s of ta s s e l s e e d - 2 (ts^)

and s ilk ie s s (sk) w ere found to be in d istin g u ish ab le fro m ta s s e l
s e e d -2 by its e lf .

A pparen tly, th is ta s s e l - s e e d gene had the

ab ility to n u llify the actio n of the s ilk ie s s gene.

P la n ts having

the co m p o sitio n ( s k - s k - ts ^ - ts ^ ) p ro d u ced seed s both in the l a t ­
e r a l a s w ell as the te rm in a l flo w e rs , and w ere fe m a le in fu n c ­
tion.

When such p la n ts w ere c r o s s e d w ith s ilk le s s individuals

h e tero zy g o u s fo r ta s s e l s e e d -2 (sk sk T s^ts^) w hich w ere m ale
in function, the r e s u lt was a p ro g en y m ade up of the sam e two
c la s s e s a s the p a r e n ts .

Sex e x p re s s io n in th is ra c e of dioecious

m a ize is th e re fo re c o n tro lle d by a single gene (Ts^)-

10
E m e rs o n (1924) a g re e d th a t sex is p ro b ab ly an e x p re s s io n
of the in te r a c tio n of s e v e ra l, p e rh a p s m any, f a c to r s lo c a te d in
d iffe re n t c h ro m o s o m e s.

He a s su m e d th a t c h a r a c te r s in g e n e ra l,

including sex e x p re s s io n , develop thro ugh the co o p erativ e in ­
flu e n c e s of g en etic f a c to r s and f a c to r s of the in te rn a l, a s w ell
as the e x te rn a l, en v iro n m en t.

He added th a t in p re v a ilin g d io ­

ecio u s fo rm s of the flo w erin g p la n ts, f a c to rs fo r m a le n e s s and
f o r fe m a le n e s s p re s u m a b ly a r e p r e s e n t in both m ale and fem a le
in d iv id u als, bu t h e re the b alance is m o re stro n g ly in fa v o r of
one o r the o th e r condition.

The ap p ro x im ate n u m e ric a l eq u ality

of ind iv id u als of the two sex es in th e se fo rm s a t once su g g ests
a ch ro m o so m e m e ch an ism s im ila r to th a t known to e x is t in
n u m e ro u s an im al g ro u p s.

The o c c a sio n a l a p p ea ra n ce of sex

in te rg r a d e s app roaching the condition of ty p ic a l h e rm a p h ro d ite s
m ay w ell be due to the influence of s e v e ra l h etero zy g o u s sex
f a c to r s of re la tiv e ly m in o r influence.
In h is re v ie w of sex e x p re s s io n in a n g io sp e rm s, A llen
(1940) c ite d the genetic b a s is fo r sex e x p re s s io n as fo rm u la te d
by C o rre n s in 1928, w hich a ssu m e d th a t all a n g io sp e rm s p o s s e s s
p o te n c ie s f o r fe m a le n e s s , c a r r i e d by a gene o r g en e-co m p lex
(G); and fo r m a le n e s s , c a r r i e d by a gene o r g en e-co m p lex (A).

11
A no ther gene o r g e n e -c o m p le x (Z) in flu en ces f o r e ac h sp e c ie s
the tim e and o r d e r of ap p e a ra n c e of m ale o r fem a le o rg an s.
In addition, a d io ecio u s s p e c ie s has genes ( Mr e a l i z a t o r s '') te n d ­
ing r e s p e c tiv e ly to w ard fe m a le n e s s (gam m a) and to w ard m a le n e s s (alpha).

This v e ry b ro a d hyp o th esis has b een the b a s is

of a n u m b e r of ex p lan atio n s of sex in h e rita n c e in the h ig h er
p la n ts .

E n v iro n m en t as a F a c to r

The en v iro n m en tal in flu en ces upon the sex e x p re s s io n
is a p ro b le m w hich does not have a c o n crete an sw e r.

It is

im p o ssib le to show th a t en v iro n m en t has no effect o r th a t it
h as a 20- p e r c e n t effect o r is a p r im a r y co n tro llin g fa c to r .
C e rta in ly , e n v iro n m en t h as an effect, fo r w ithout en v iro n m en tal
change, no life would e x ist.

F o r exam ple, spinach seed, if kep t

in a d ry c o n ta in e r, would ev en tu ally die, o r if they w ere kept
in a w a rm , m o ist, d a rk condition co n stan tly , th ey would in itia te
grow th, b u t soon die.

In o r d e r to m ain tain grow th and dev elo p ­

m e n t th ro u g h its com p lete re p ro d u c tio n cycle, a sp in ach seed
m u s t go th ro u g h a s e r ie s of ev e r-c h a n g in g e n v iro n m e n ts.

It

12
is th e se e v e r-c h a n g in g en v iro n m e n ts w hich p e r m it the gen etic
co m p lex to e x p r e s s the c h a r a c te r s of the o rg a n ism .
The d e g re e of influence w hich e n v iro n m en t has o v er the
e x p re s s io n of c h a r a c te r s is an o th er question.

S chaffner (1927)

took the e x tre m e view, and concluded th a t sex was p u re ly p h y s i­
o lo g ical, and in no way dependent upon se g re g a tio n and co m b in a­
tio n of the u n its of c h ro m o so m e s.

He p la c e d em p h asis upon e x ­

te r n a l f a c to rs su ch as lig h t, te m p e r a tu r e , and so il, and b eliev ed
th a t e ith e r sta m in a te o r p is tilla te p la n ts c a r r i e d w ithin th e m ­
s e lv e s the p o te n tia litie s of e x p re s s io n of the opposite sex.

T his

l a tte r b e lie f of S chaffner is u su a lly accep ted , but in the c a se of
c e r ta in dio eciou s p la n ts , the conditions n e c e s s a r y to r e a liz e
the p o te n tia litie s of changing sex would be so se v e re th a t it
would r e s u l t in the d eath of the o rg a n is m .

F r o m o b se rv a tio n s

in spin ach , it a p p e a rs th a t c e r ta in m ale types a re

so co m p letely

" o v e rb a la n c e d ” on the an d ro ecio u s side th a t en v iro n m en tal
ch an g es, no m a tte r how s e v e re , would not change the sex of
the p la n t.

The sam e is tru e of the stro n g fem a le p la n ts .

This

c o m p a re s w ith the conditions e x istin g in m o s t a n im a ls.
As the s tre n g th s of the an d ro ecio u s and gynoecious c o n ­
ditio n s tend to b alan ce each o th e r, en v iro n m en t b eco m es an

13
im p o rta n t f a c to r .

E vidence of th is is shown in the effects of

the w in te r (g reenhouse) g e n e ra tio n s c o m p a re d to sp rin g (field)
g e n e ra tio n s .

T h ree lin e s of in te rs e x e s d iffe re d m a rk e d ly in

th e ir sex e x p re s s io n , while dio ecious s tr a in s m a in tain ed the 1:1
r a tio u n d er s im ila r con d itio n s.

Sugim oto (1947) noted d iff e r­

en c e s c o r r e la te d w ith en v iro n m en ts of sp rin g and autum n p la n t­
in g s.

The autum n p la n tin g s w ere influenced to a l e s s e r d eg ree

th an w e re h is sp rin g p la n tin g s.
The and rom ono ecio us p la n ts of C itru llu s v u lg a ris u sed
by R osa (1928) w ere m o re se n sitiv e to en v iro n m en tal conditions
th a n w e re the androm o noecio us p la n ts of C ucum is sativ a, as the
sta m e n s of h e rm a p h ro d itic flo w ers w ere not alw ays equally d e ­
veloped.

In o th e r v a r ie tie s of m onoecious c u c u rb ita c e a e , W hit­

a k e r (1931) re p o r te d th a t the ra tio of m ale flo w e rs to fem ale
flo w e rs v a r ie s w ith seaso n , and also w ith v a rie ty .
H ow ever, when the h e rm a p h ro d itic o r m onoecious condition
b eco m es g e n e tic a lly sta b iliz e d , en v iro n m en t once m o re b eco m es
a m in o r f a c to r .

It is m ain ly when a sp ecie s is in the p r o c e s s

of changing g e n e tic a lly , due to c o n tro lle d b reed in g , th a t e n v iro n ­
m e n t e x e r ts its g r e a te s t influence on the e x p re s s io n of c h a r a c ­
te rs .

14
C ytogenetic I n te r p r e ta tio n s of Sex E x p re s s io n

In a n im a ls and d ioecious p la n ts th e re m u s t be a s y ste m
w h ereb y one s e x w ill n o t p re d o m in a te and p o s sib ly e lim in ate
the s p e c ie s .

D isju n ctio n betw een h e te ro m o rp h ic sex c h ro m o so m es

is one s y ste m w hereby the two sex es w ill be m a in tain ed in a p ­
p ro x im a te ly equal n u m b e rs .

W here no h e te ro m o rp h ic c h ro m o ­

so m es a r e v is ib le , and a ll ch ro m o so m e p a ir s ap p ea r to be h o ­
m ologous, th e p re s e n c e of a c r o s s o v e r s u p p r e s s o r fo r a s e g ­
m e n t of a p a ir of c h ro m o so m e s w ill give the sam e actio n as
if the c h ro m o so m e s w ere nonhom ologous; th a t is , a 1:1 ra tio
f o r the p a r ti c u la r seg m en ts is m ain tain ed .

If th e se seg m en ts

a r e c o m p ris e d of s e x -d e te rm in in g gen es, then th e re is in effe c t
an X-Y m e c h a n ism w ithout h e te ro m o rp h ic p a i r s of c h ro m o so m e s.
M cClung (1902) stu d ied the m a le s of s e v e r a l o rth o p te ra n s
and su g g e ste d th a t the u n p a ire d o r ’A c c e s s o r y " ch ro m o so m e
w as the m ale sex d e te r m in e r .

L a te r , in the fe m a le , he found

th is ch ro m o so m e w as p r e s e n t tw ic e--X X fem a le; XO m ale.
W ilson (1905) stu d ied the in s e c t L ygaeus, and found in
the fe m a le two X c h ro m o so m e s, but in the m ale th e re w as an
unequal p a ir , one being an X ch ro m o so m e and the o th e r being

15
sm a lle r.

T his w as c a lle d the Y c h ro m o s o m e - -X fe m a le ; XY

m a le .
In b i r d s and le p id o p te r a it is the m a le which is h o m o ­
g a m e tic , and the sym bols Z and W a r e u s e d - - Z W fem a le;

ZZ

m a l e - - o r the W m ay be ab sen t, the fem a le being ZO.
B rid g e s (1921,

1922, 1925, 1932), w orking with D r o s o ­

phila, found a tr ip lo id fe m a le which, when c r o s s e d with a d i ­
p lo id m a le , p ro d u c e d in t e r s e x e s .

His concept of genic b alan ce

o r s e x index w as f o r m u la te d to show the r e la tio n of X c h r o m o ­
s o m e s to the a u to so m e s .

More exactly, the n e t m ale tendency

of a s e t of a u to so m e s is l e s s than the n et fem a le tendency of
an X c h ro m o s o m e .

He s u g g ested th a t the X c h ro m o so m e (fe­

m ale tendency) be r e p r e s e n t e d by 100 and the au to so m es (male
tendency) be r e p r e s e n t e d by a l e s s e r amount, a p p ro x im a te ly 80.
F r o m th is he c a lc u la te d a sex index in which 1.25 o r l a r g e r
was fe m a le , 0.63 o r lo w e r was m a le , and betw een 0.63 and 1.25
was the range of in t e r se x e s (Table I).
In the dioecious p la n t Rumex a c e to s a , f e r t i l e h e r m a p h r o ­
ditic types a r e d e s c r ib e d by Ono (1935) in a s e r i e s p a r a lle lin g
the in t e r s e x e s of D ro so p h ila.

Since polyploidy in Rumex has

b e e n p u sh ed h ig h e r, to the heptaploid, th e r e is an even g r e a t e r

16
TABLE I
SEX INDICES IN DROSOPHILA
(a fte r B ridges)
Sex

F o r m u la

X 100

A 80

Sex Index

Super fe m a le

2N- -3X2 A

300

160

1.88

F e m a le

4N- -4X4A

400

320

1.25

F e m a le

3N- -3X3 A

300

240

1.25

F e m a le

2N- -2X2 A

200

160

1.25

F e m a le

1N- - 1X1A

100

80

1.25

I n te r s e x

4N- -3X4 A

300

320

0.94

In te r s e x

3N- -2X3 A

200

240

0.83

Male

2N- -1X2 A

100

160

0.63

Male

4N- -2X4 A

200

320

0.63

Super m a le

3N- -1X3A

100

240

0.42

17
v a r i e t y of ty p e s.

H ow ever, all types with a sex index of 0.63

o r lo w e r w e r e m a le , those with a s e x index of o v er 0.63 and
u n d e r 1.25 w e re in t e r s e x e s , and a ll types w ith a sex index of
1.25 w e re f e m a le s , ex cep t f o r one c a s e .

This c a s e was a t r i -

p lo id which con tain ed th r e e X c h ro m o s o m e s and one e x t r a autosom e (3X3A + a) and was an in te r sex.

However, an o th e r in d i­

vidual of the sam e fo r m u la (3X3A + a) was a fe m a le .

This

su g g e s ts th a t the au to so m e s d iffer am o n g st th e m s e lv e s in the
p o ten cy of the m a le genes, and p e rh a p s the m a jo r p a r t of the
m a le effec t is due to a p a r t i c u l a r two of the six a u to so m e s.
In two s e p a r a te r a c e s of L e b is te s , Winge (1922-1934)
found a m a r k e d in h e rite d tendency to w ard the p ro d u ctio n of
f e m a le s w ith m a le - li k e gonopodia.

These

" m a s c u l in iz e d " f e ­

m a le s w e re f u r t h e r p e c u l ia r in th a t the X -lin k ed p a t te r n s , fo r
which they w e re h etero zy g o u s, showed up fain tly .

The n o r m a l

f o r m u la f o r the two sex es is XX fe m a le , and XY m a le .

By

c r o s s in g to g e th e r th e se in h e rite d m ale te n d en cies, the two s e ts
au gm en ted e a c h o th e r and r e s u lte d in a s m a ll p r o p o r tio n of XX
individuals th a t w ere g en etically , phenotypic ally, and fun ction ally
m a les.

They showed c h a r a c t e r i s t i c s c a r r i e d by the X of the

f a th e r and a lso by the X of the m o th e r.

When th e se XX m a le s

18
w e re c r o s s e d to s ta n d a r d f e m a le s , all of th e i r o ffsp rin g w ere
f e m a l e s , XX in c o n stitu tio n and supposedly h etero zy g o u s fo r
about half of the m a sc u lin iz in g genes p r e s e n t in the au to so m es
of t h e i r f a th e r .

A fte r th r e e g e n e ra tio n s of b a c k c r o s s in g th e se

XX m a le s to th e ir d a u g h te r s , a co m p letely m ale individual a p ­
p e a r e d among the o ffsprin g .

When th is XX m ale was c r o s s e d

to s i s t e r s , about half of the offspring w e re m a le s .
Thus, a new r a c e was e s ta b lis h e d , homozygous fo r the
X and f r e e f r o m the Y.

In this r a c e the X c h ro m o so m e has

stopped being the s e x - d if f e r e n tia l c h ro m o so m e and the X -b o rn e
c h a r a c t e r s a r e now in h e rite d equally f r o m both se x e s, and a r e
th e r e f o r e

" a u to so m a l"

in type.

Sex differen tiatio n has been

t r a n s f e r r e d to a c h ro m o s o m e th at was f o r m e r l y an autosom e,
th ro u g h the acc u m u latio n of m a le -te n d e n c y genes c o n trib u ted
b y two s e p a r a t e r a c e s which had b e e n s e le c te d fo r th e ir m a s ­
culinizing e ffe c ts, until th e ir influence was stro n g enough to
give d ecisiv e d ifferen tiatio n .

The new r a c e is fe m a le h e te r o -

g a m e tic , while the old r a c e is m ale h e te ro g a m e tic.
As the r e s u l t of th e se findings, Winge concludes th a t
n u m e ro u s fe m a le - te n d e n c y and m a le -te n d e n c y genes e x is t in
both a u to so m e s and sex c h ro m o s o m e s alike, and the s e x is the

19
o u tco m e of the sp ecific b a la n c e betw een th e se g en es, among
which th e r e is no v alid d is tin c tio n as to " p r i m a r y "
versu s

s e x genes

" m o d ifie rs."
Sex d e te r m in a tio n in h y m e n o p te ra and in a few o th e r

f o r m s h as long b een f o r m u la te d a s N m a le and 2N fe m a le .

If

IN g iv es a m a le , th e n tw ice the sa m e N should also give a
m a le .

P e r h a p s the e r r o r li e s in the assu m p tio n th a t the sa m e

two s e ts of c h ro m o s o m e s a r e p r e s e n t in the fe m a le .

In asm u ch

as the fe m a le a r i s e s f r o m f e r tiliz a tio n , h e r constitution m a y
alw ays be N /N ' while the m ale is e ith e r N o r N 1.
O ccasio n ally , b ip a re n ta l m a le s a r e o b s e rv e d in H a b r o b r a c o n ; Whiting (1933) developed an hypothesis on the a s s u m p ­
tion th a t the n o r m a l fem a le is a h etero zy g o te betw een two dif­
f e r e n t i a l p a i r s of f a c t o r s , o r m ultiple com plexes of f a c t o r s ,
which m a y be d e sig n a te d X

a

b
and X , re s p e c tiv e ly .

m a le s a r e of two genotypes, one c a r r y in g the X
the o th e r the X

com plex, o r c h ro m o so m e .

a

N o rm a l
com plex and

The b ip a re n ta l

a a
b b
m a le s would thus be X X AA o r X X AA, with the sam e genic
a
b
b a la n c e as the n o r m a l haploid m a le s , that is X A o r X A.

The

a
b
f e m a le s would have a d istin ctiv e balan ce X A /X A, o r the f e ­
m a le is Na /N^ and the m a le s N

o r N /N , N

o r N /N .

20
Then the p o s tu la te th a t IN r e s u l t s in m ale and 2N in
fe m a le is n o t the c a s e , but IN and 2N a r e both m a le while the
f e m a le is N N 1.
In the c a s e of H a b ro b ra c o n , no d ir e c t effect on i n t e r s e x
is shown, b ut due to its in t e r e s tin g

and com plex genetic m a k e ­

up, the a b o v e -m e n tio n e d sch em e is im p o rta n t to the genetic
b a la n c e of s e x - d e te r m in a tio n th eo ry .
G o ld sch m id t (1915-1934) has worked out one i n t e r p r e t a ­
tion of

s e x in h e rita n c e in the moth, L y m a n tria d i s p a r .

He has

found two r a c e s , one of which is weak (European) and the o th e r
a stro n g (Japanese) r a c e fo r sex.

He has fo r m u la te d the i n t e r ­

p r e ta tio n th a t M (male) gene is lo c a te d on the Z ch ro m o so m e
and the F (female) gene is in the
F :M

= fe m a le ; F:MM = m ale; o r

c y to p la sm of the fe m a le , thus
ZW = fem a le; ZZ = m a le .

How ever, a stro n g F with weak MM r e s u lt s in an i n t e r sex,

and a weak F

with a stro n g M also r e s u lt s in an in te r s e x .

Winge (1937) s h a r p ly c r it ic i z e d G o ld sch m id t's f o rm u la tio n
and o ffe re d an a lte r n a tiv e explanation on the following b a s is :
1.

The Z c h ro m o s o m e contains a n e t m a sc u lin e tendency,

stro n g (M50) in the J a p a n e s e r a c e and weak (M10) in the E u r o ­
pean r a c e .

21
2.

The W c h ro m o s o m e h as a n e t fem inine tendency, v e r y

s tro n g (F70) in the J a p a n e s e r a c e and weak (F24) in the E u ro p e a n
race.
3.

All a u to so m e s c a r r y sex g en es, some of which pull

in a m a s c u lin e d ire c tio n , som e in a fem inine; in the Jap an ese
r a c e the fem in in e a u to so m a l f a c to r s a r e m a rk e d ly p r e p o n d e r ­
an t (F20), b ut only slig h tly so in the E u ro p ea n r a c e (F4).
W arm ke (1946), w orking with polyploidy in M elan d riu m
dioicum , found th a t s e x was d e te r m in e d by the X/Y ra tio , and
th a t the a u to so m e s co n trib u ted little o r no effect.

M elan d riu m

has d is tin c t h e te r o m o r p h ic sex c h ro m o s o m e s th at can be counted,
and the r a t i o s d e te r m in e d in polyploids.

It was an XXXX/Y

p la n t which was in te r sex, indicating th a t the Y was strong in
m a le - d e te r m in i n g genes, while the X was weak in f e m a l e - d e ­
te rm in in g gen es, although XX/Y and XXX/Y show o cca sio n al
in t e r sex f lo w e r s .
D o ris Love (1942) m entioned the p o s s ib ility th at the
cau se of one type of in t e r sex in M eland rium was due to a
tr a n s l o c a ti o n betw een the X and the Y c h ro m o so m e .

F rom m ea­

s u r e m e n t s of the X and Y c h ro m o s o m e s of the in te r sex she
su g g e s te d th a t it was o rig in a lly an XX com position, but th a t a

22
s e c tio n of the Y c h ro m o s o m e was tr a n s l o c a te d on to the s h o r t
a r m of the X.
T h ese a r e but a few of the r e p o r t s w here s e x d e t e r m i n a ­
tion h a s b e e n studied, but they show definite p a t te r n s which
should be c o n s id e r e d in fo rm u la tin g a genetic b a s is f o r sex
e x p r e s s io n .

However, the c o m p le x itie s of sex e x p r e s s io n m ay

be of su ch a n a tu re th at m any u n r e la te d s y s te m s m a y e x is t in
the m any and v a r i e d p a t t e r n s of sex.

CYTOLOGICAL INVESTIGATIONS OF SEX EXPRESSION
IN SPINACIA

Diploids

R eview of l i t e r a t u r e .

Winge (1924) ex am in ed the c h r o m o ­

s o m e s in S pinacea o l e r a c e a L. and found no h e te ro m o rp h ic p a i r s .
N e v e r th e l e s s , he concluded th at one of the six p a i r s of c h r o m o ­
s o m e s m u s t be s e x - d e te rm in in g , w h ere the X and Y a r e alike,
and of the sam e a p p e a ra n c e as the a u to so m e s, and can c o n s e ­
quently show c r o s s in g o v e r.
O th e r in v e s tig a to r s of the cytology of S. o le r a c e a who
f a ile d to find h e te r o m o r p h ic c h ro m o so m e p a i r s include T u sch n jakowa (1929), Sinoto (1929), Haga (1934), L o r z (1937), and A r a r a tj a n
(1939).
Haga ex am in ed the m a c ro sp o re m e io s is , as well as m i c r o sp o re m e io s is , and found no d iffe re n c e s between the two se x e s .
However, A r a r a t j a n did show the p r e s e n c e of a h e te ro m o rp h ic
p a i r in S. te ta n d r a Stev. which had six p a i r s th at r e s e m b l e d the
six p a i r s in S. o l e r a c e a , except fo r the h e te ro m o rp h ic p a i r .
D o lch er (1949) k ary o ty p e d S. tu r k e s ta n ic a M. M. ILijn, but he
m ade no m en tio n of the p r e s e n c e of h e te ro m o rp h ic ch ro m o so m e

24
p a irs.

He found six p a i r s , but could d istin g u ish only the s a t e l ­

l i te d and the lo n g e s t c h ro m o s o m e s with c e r ta in ty .
T h e r e h as b e e n m u ch d is a g r e e m e n t as to the r e la tiv e
s i z e s of the c h r o m o s o m e s in Spinacia o le ra c e a :

Sinoto (1929)

found one l a r g e , two m edium , th r e e sm all; Tuschnjakowa (1929)
found th r e e l a r g e and th r e e

sm all; Haga (1934) showed som e

d if f e r e n c e s in siz e , but did not place th em in any p a r t i c u l a r
order.

L o r z (1937) d e s c r ib e d th e m as two la r g e , two m edium ,

and two sm all; A r a r a t j a n (1939) did not place the c h ro m o s o m e s
of 15. te tr a n d a into s ize c la s s ific a tio n s , but his draw ings in d i­
c a te d th a t th e re was one la r g e (h ete ro m o rp h ic), two m edium ,
and th r e e s m a ll p a i r s , which is roughly as Sinoto grouped th e m
f o r S, o l e r a c e a .

He also suggested the p o s s ib ility of k a r y o -

r a c e s o c c u r r in g within S p in acia.
In conjunction with the gen etical study of s e x in h e rita n c e
in spinach, a cytological study was also in itia ted to d e te rm in e
any d iff e r e n tia l c h ro m o s o m a l a r r a n g e m e n t sp ecific f o r any
given s e x type.

M a te r i a ls and m e th o d s .

The so urce of m a t e r i a l fo r this

study cam e f r o m two u n r e la te d in te r sex plants and p u r e m a le
p la n ts .

One line was a p u r e - b r e e d in g i n t e r s e x line developed

25
by M r. W. F e r g u s o n , of the C anadian D e p a rtm e n t of A g r ic u ltu r e .
T his line w as d e s ig n a te d C - l .

The o th e r i n t e r s e x line o r ig in a te d

f r o m an open p o llin a te d i n t e r s e x p la n t followed by two g e n e ra tio n s
of s e lfe d i n t e r s e x e s .

I n te r s e x p la n ts s e le c te d f r o m the pro g en y

of the second g e n e ra tio n of selfed in t e r sexes all b r e d tr u e f o r
the in t e r sex condition.

This line was d esig n ated L -1 5 .

The

p u r e m a le p la n ts w ere s e le c te d f r o m a planting of the c o m m e r ­
cial v a r ie ty , Long Standing B loom sdale, which was the v a r ie ty
f r o m which both i n t e r s e x lin e s o rig in ated .

The p u re m a le p la n t

was d e sig n a te d A - 10.
A n th e rs w ere tak en f r o m the flo w e rs of p u re m a le p la n ts ,
and f r o m i n t e r s e x p la n ts .

Whole flo w er c l u s t e r s w e re fixed in

a 3:1 a b so lu te a lc o h o l-g la c ia l acetic acid solution f o r f r o m
to 24 h o u rs a t ro o m te m p e r a t u r e .

F r o m th e se

12

" f ix e d " flo w er

c l u s t e r s the a n th e r s w ere e a s ily d is s e c te d out u n d er a d i s s e c t ­
ing m ic r o s c o p e .

P r e p a r a t i o n s w ere made using the iro n a c e to -

c a r m in e technique and m ade p e r m a n e n t with diaphane.
F o r the so m a tic d iv isio n s, ro o t tips w ere tak en f r o m
f r e s h l y g e r m in a te d seed s and p la c e d in a 0.01 p e r c e n t aqueous
solution of co lch icin e fo r 2 h o u rs b e fo re being fixed in the sam e

26
m a n n e r as the a n t h e r s .

A c e to - c a r m in e s m e a r s w e re then m ade,

and the slid e s w e re m ade p e r m a n e n t with diaphane.

M eiotic o b s e r v a ti o n s .

The g am etic c h ro m o so m e n u m b e r

of s ix (2n = 12) was found, and is in a g r e e m e n t with all o th e r
r e p o r t s on the c h ro m o s o m e count of Spinacia o l e r a c e a .

It is

d ifficu lt to d is tin g u is h m e io tic c h ro m o s o m e s on a s t r i c t l y size
b a s i s , but d ia k in e s is co n fig uratio n s a r e quite c h a r a c t e r i s t i c
(F ig u re A).

T h e re a p p e a rs to be one la r g e p a i r of c h ro m o s o m e s

w ith s u b te r m in a l k in e to c h o re s whose a r m s f o r m a con fig u ratio n
th a t v a r i e s f r o m a rig h t angle to a s tr a ig h t line.

Two s m a l l e r

c h r o m o s o m e s with su b m ed ian k in e to c h o re s , one of which f o r m s
and (X) with two s h o r t a r m s , and the o th e r one f o r m s a (Y) o r
an open 270- d e g r e e a r c .

One m e d iu m ch ro m o so m e often f o r m s

a rin g , and two s m a l l e r c h ro m o s o m e s a r e a s s o c ia te d with the
n u cleo lu s in lin e s A - 10 and L -1 5 .

Where only one c h ro m o so m e

is a s s o c ia te d with the n ucleo lu s, the o th e r one f o r m s a sm all
rin g .
M eio sis is r e g u l a r and the nucleolus is conspicuous at
p ach y ten e, and r e m a in s about the sam e size until la te d ia k in e s is ,
a f te r which it d is a p p e a r s .

27

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FIGURE A
KARYOTYPE OF SPINACIA OLERACEA L.

1.

D ia k in e sis, P o lle n m o th e r cell (A10).

2.

C - - m i t o s i s , Root tip c e ll (A10).

3.

K aryotype of m eio tic c h ro m o s o m e s.

4.

K aryotype of so m a tic c h ro m o s o m e s.

The o r d e r l y a r r a n g e m e n t of m eiotic c h ro m o s o m e s and
so m atic c h ro m o s o m e s shoyrs the r e la tiv e size d iffe re n c e s and
the lo c a tio n of the k in e to c h o r e s between the c h ro m o s o m e s of
the s a m e c e ll and b etw een m eiotic and som atic c h ro m o s o m e s.

28
At d ia k in e s is , the two s m a ll p a i r s of c h ro m o s o m e s a r e
a s s o c ia t e d w ith the nu cleo lus in p la n ts of lin e s L-15 and A - 10
(P late I, No. 3), b u t only one of th e m a p p e a r s to be so a s s o ­
c ia te d in C - l lin e.

Only one of the two s m a ll p a i r s of so m atic

c h r o m o s o m e s c l e a r l y shows t r a b a n ts .

H ardh (1939) found th a t

in nine v a r i e t i e s of spinach, six v a r i e t i e s had one p a i r of s a t e l ­
lite d c h r o m o s o m e s , while th r e e v a r i e t i e s had two such p a i r s .
It is p o s s ib le th at both n u c le o la r c h ro m o s o m e s found in the L-15
in t e r sex and in the p u re m a le s a r e s a te llite d c h ro m o s o m e s, but
the tr a b a n ts a r e

so s m a ll on one p a i r th at it is difficult to

show them .
At M etaphase I it is difficult to d istin g u ish the d ifferen t
chrom osom es.

Two with the subm edian k in e to c h o re s , and two

s m a ll ones which a r e f i r s t to s e p a r a te , can be d istin g u ish ed
(P late III, No. 4).

At no stage is th e re any evidence of the

e x iste n c e of a h e te r o m o r p h ic p a i r in any line exam ined.

It

m a y be p o in ted out, how ever, th a t fa ilu re to find such a p a i r
is no evidence that such a p a i r does not ex ist.

The differen ce

m a y be too s m a ll to be re so lv e d , o r m ay c o n s is t only of a
d iffe re n tia l p a irin g seg m en t.

29
T h e re is no tr u e in t e r k in e s is , the c h ro m o s o m e s going
m o r e o r l e s s d ir e c tly f r o m

Telophase I into M etaphase II.

At

M etap h ase II the c h ro m o s o m e s often a r r a n g e d th e m s e lv e s in a
c i r c l e of five, w ith the s m a l l e s t one in the c e n te r , and th is s m a ll
one is often the f i r s t one to move out fr o m the m e tap h ase p la te .
T elo p h ase II and t e t r a d fo rm a tio n p r o c e e d in a r e g u la r m a n n e r.
E x ce p t fo r the d ifferen ce in the n u c le o la r c h ro m o s o m e s,
m e io s is was the sam e in the p u re m ale and both i n t e r s e x lin e s .

T e tra p lo id s

Review of l i t e r a t u r e .

T e tra p lo id spinach has b een o b ­

ta in e d by Tandon (1951), W arm ke and B la k eslee (1939), and o th e r
in v e s t ig a to r s , but a cytological study has not been r e p o rte d .
Tandon (1951) counted the Anaphase I c h ro m o s o m e s , but
m ad e no m ention of f u r th e r m eio tic o b s e rv a tio n s.

He did note

th at the p o llen s t e r i l i t y was 15 to 40 p e rc e n t, but made no m e n ­
tion of a b n o rm a l pollen.

M a te r i a ls and m e th o d s .

The te tra p lo id p la n ts u sed in

the cytological study w ere induced fro m diploid seed of a s t r a i n
of p u r e - b r e e d i n g in t e r sex p la n ts by the use of co lch icin e.

The

se e d was soaked in w a te r fo r 24 h o u rs , a fte r which tim e the

30
r a d i c l e s had e m e r g e d to about an eighth of an inch, and w e re
then so aked in a 0 .2 - p e r c e n t aqueous solution of colchicine f o r
an ad d itio nal 24 h o u rs .
p o ts .

They w e re then p la n ted in soil in clay

Out of one h u n d red seed s thus tr e a te d , th e re w e re six

which showed som e effect of the tr e a tm e n t , b u t only two of th e se
s u rv iv e d , both of which w ere i n t e r s e x p la n ts .
The grow th was v e r y slow, and a f te r six tr u e le a v e s
w e r e f o r m e d , the p la n ts w e re p la c e d in a 16-h o u r photoperiod
w hich s tim u la te d f l o w e r - s t a l k developm ent, so the full vegetative
stage of the p la n ts was n e v e r attain ed.

However, the l a r g e s t

of the le a v e s which w e re developed w ere heavily savoyed and
v e r y thick.
a p p e a ra n c e .

As the flo w er s ta lk fo rm e d , the p la n ts had a c o a r s e
The s te m was thick and the le a f p e tio le s tended

to s p lit w h ere they w ere attac h ed to the stem .

Both p lants

w e re in te r se x e s and s e t a " n o r m a l " n u m b e r of s e e d s .

The

p la n ts w ere h eav ily b ra n c h e d , w hich was c h a r a c t e r i s t i c of the
s t r a i n f r o m which the seed was taken.

One plan t had its m ain

flo w er stalk f a s c ia te d to a th ic k n e s s of 2 in ch es, and then the
f a s c ia tio n s e p a r a te d into m any growing points as the p la n t a p ­
p r o a c h e d m a tu r ity .

The seed s w ere slightly l a r g e r than the

diploid seed, and the s e e d co at was conspicuously w rinkled.

31
The p la n ts continued to develop about tw o - th ir d s as r a p id ly as
a diploid p la n t w hich was grow n u n d e r the sam e conditions.
The m a t e r i a l f o r the study of m e io s is was p r e p a r e d in
the sam e m a n n e r as it was f o r the diploids.

The p ollen m o th e r

c e lls w e re e a s il y b ro k en , so m o re c a r e had to be tak en in the
p r e p a r a t i o n of s m e a r s than was n e c e s s a r y with the diploids.

M eiotic o b s e r v a ti o n s .

The c h ro m o so m e count was 2n =

24, as shown a t M etaphase I and M etaphase II (P late III, No.
2, 3).

At M etaphase I th e re a r e at l e a s t two tr iv a le n ts (Plate

III, No. 7).

H ow ever, no a tte m p t was m ade at this tim e to

analyze the c h r o m o s o m e s as to the n u m b e r of u n iv alen ts, b iv a le n ts , t r i v a le n t s , o r q u ad riv a le n t s.

T h e re w ere, how ever, a

c o n s id e r a b le n u m b e r of lagging c h ro m o s o m e s and b r id g e s p r e s ­
ent.

M eio s is , n e v e r t h e le s s , was r e g u la r , f o r the m o s t p a r t , up

to the fo rm a tio n of t e t r a d s .

Soon a f te r the Telophase II c h r o ­

m o s o m e s began to lo se th e ir identity, cy to k in esis was in itia ted
fo r the fo r m a tio n of p ollen g r a in s .

The p a t te r n of cytokinesis

was u s u a lly found to be i r r e g u l a r , which r e s u l t s in a n u m b e r
of m i c r o c y te s in the ’ 't e t r a d "

(Plate II, No. 8).

Wilson (1946)

d e s c r ib e d the f o r m a tio n of m ic r o c y te s in addition to the n o r m a l
fo u r c e lls in the t e t r a d s of tr ip lo id and te tr a p lo id banana, and

32
a ttr ib u te d th e m to independent division of " o m i t t e d 1' o r
chrom osom es.
are

" la g g in g "

While th e r e a r e c e r ta in ly c h ro m o s o m e s which

" o m i t t e d 11 o r " la g g i n g " in th is m a te r ia l , th e re a r e in m any

c a s e s m o r e c e lls p e r

" t e t r a d " than one would expect f r o m the

a v e ra g e n u m b e r of s eco n d -an ap h a se la g g a r d s .
as m a n y o d d - c e lle d " t e t r a d s "

Also, th e re a r e

as th e r e a r e e v e n - c e lle d ones

(Table II).
The p o llen developed f r o m th e se c e lls is ju s t as v a ria b le
in size as the c e lls in the te tr a d , the s m a l le s t m ic ro c y te being
able to develop th ick en ed w alls c h a r a c t e r i s t i c of n o rm a l pollen
g r a in s (P la te II, No. 9).
The " t e t r a d s "
tran sv erse

counted w ere taken at random , f r o m one

sweep of the slide containing s e v e r a l an th er s m e a r s ,

u sin g the high d r y le n s .

All c e lls which could a c c u r a te ly be

counted w e re counted as they a p p e a re d in the field.
In T e tr a p lo id C th e re w ere eight " t e t r a d s " which c o n ­
ta in ed fo u r e q u a l - s i z e d c ells and one sm all m ic r o c y te , and in
te n o th e r " t e t r a d s " th e r e w ere fo u r e q u a l- s iz e d cells and one
m e d iu m - s iz e d m ic r o c y te .

Of the f o rty " t e t r a d s "

counted, th e re

w e re t h i r t y - f o u r which had fo u r e q u a l- s iz e d c e lls , of which
tw en ty-n in e had additional c e lls .

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34
In T e tr a p lo id A th e r e w ere tw enty-nine ' ' t e t r a d s 11 which
c o ntain ed fo u r e q u a l - s i z e d c e lls , of which twenty-two had a d d i­
tio n al c e lls .
The " t e t r a d s ' 1 w hich co ntained l a r g e n u m b e rs of c e lls
did not a p p e a r to have any o r d e r l y a r r a n g e m e n t of c e lls within
the " t e t r a d , " but in s te a d , r e s e m b le d a sack of m a r b l e s .
l a r g e s t n u m b e r of c e lls contained in a " t e t r a d "

The

of the t e t r a ­

p lo id was f o u rte e n .
A c l o s e r ex am inatio n of the te tr a d s of diploid a n th e rs
r e v e a le d th a t an o c c a sio n a l m ic ro c y te was p r e s e n t in the t e t r a d s .
They w e re so o b s c u r e d as to p a s s unnoticed u n le ss one was a c ­
tu a lly looking f o r th em .
Some p r e l i m i n a r y in v e stig atio n s of the seed f r o m the
two te tr a p lo id p la n ts have shown th a t T e tra p lo id A had a g e r ­
m in atio n of 90 p e r c e n t, and T e tra p lo id C had a g e rm in a tio n of
20 p e r c e n t.
Tr> T e tr a p lo id A, r o o t tips w ere exam ined, and in four,
w h ere m ito tic f ig u r e s w e re o b serv ed , they w ere all diploid.
The T e tr a p lo id C r o o t tip s w e re exam ined and counts w ere
m ad e in two, both of which w ere te tra p lo id .

35
D is c u s sio n

T h e re a p p e a rs to be no sig n ifican t cytological differen ce
b etw een lin e s of sp in ach showing d iffe re n t d e g r e e s of sexual
e x p r e s s io n .

No evidence of the p r e s e n c e of a h e te ro m o rp h ic

p a i r of c h r o m o s o m e s was found in any line.

This, as noted

p re v io u s ly , n eed only m e a n th a t the d ifferen ce betw een the X
and Y c h r o m o s o m e s is not of a n a tu re o r extent which is m o r ­
p h o lo g ically d istin g u ish a b le .
The c o n s is te n c y of the 1:1 sex d istrib u tio n , as well as
m o r e d e ta ile d genetic data p r e s e n te d below, in d icate s the p r e s ­
ence of som e f o r m of s e g re g a tio n m e c h a n is m equivalent to the
s ta n d a r d X-Y s y s te m .
It a p p e a r s th a t th e -a b n o r m a l " t e t r a d s 1' a r e the r e s u l t s
of c h r o m o s o m e s which a r e s e p a r a te d f r o m the m a in m a s s e s of
T elo p h ase II c h r o m o s o m e s .

Telophase II p r o c e e d s r e g u la r ly ,

but b efo re cy to k in esis is in itia ted , the ch ro m o s o m e s a p p e a r to
s p r e a d out.

Then cy to k in esis b eco m es i r r e g u l a r , and actu ally

a p p e a r s to cut off c e r t a in n u m b e rs of the c h ro m o s o m e s to f o r m
m i c r o c y te s .

36
PLATE I
MEIOSIS IN DIPLOID SPINACIA O L E R A C E A L .

1.

P a c h y te n e --(lin e

C - 1 i n t e r sex).

2.

D i a k i n e s i s - - ( l i n e A - 10 m a le ) .
T his show s th e c h a r a c t e r i s t i c
f o r m s of the c h r o m o s o m e s , and the two n u c l e o l a r c h r o m o ­
som es.

3.

D ia k i n e s i s - -(lin e A - 10 m a le ) .
T h is sh ow s th e two n u c l e o l a r
c h r o m o s o m e s a t ta c h e d to the n u c le o lu s a f t e r th e y h av e b e e n
f o r c e d out of th e c e l l s .
A ll of th e n u c l e o li show n h a v e two
a t ta c h e d c h r o m o s o m e s .

4.

L a te D i a k i n e s i s - - ( l i n e A - 10 m a le ) .
The c h r o m o s o m e s a r e
r e d u c e d to n e a r M e ta p h a se I s iz e .
The n u c le o lu s is p r o m ­
in e n t and shows the two a t ta c h e d c h r o m o s o m e s .

5.

M e ta p h a s e I - - ( l i n e A - 10 m a le ) .
T he c h r o m o s o m e n u m b e r
of tw elve is r e a d i l y d e t e r m i n e d .
T h e r e a p p e a r s to be no
e v id e n c e f o r the p r e s e n c e of a h e t e r o m o r p h i c c h r o m o s o m e
p air.

6.

T e lo p h a s e I — (line C - l i n t e r s e x ) .
The c h r o m o s o m e s c o m ­
p l e t e l y lo s e t h e i r id e n tity and M e ta p h a s e II fo llo w s w ith o u t
d elay .

7.

T e lo p h a s e I I - - ( l i n e A - 10 m a le ) .

8.

T e t r a d s - - (line A - 10 m a l e ) .
The f o u r g r o u p s of T e lo p h a s e
II c h r o m o s o m e s a r e c u t off in to in d iv id u a l m i c r o s p o r e s .
T h e h e t e r o p y c n o t i c r e g i o n s r e m a i n v is ib l e in th e m i c r o s p o r e s .

9.

P o l l e n - - (d ip lo id i n t e r s e x ) .
8 m i c r o n s in d i a m e t e r .

S c a le --O n e

T h e y a r e u n if o r m , and ab o u t 7

d i v i s i o n i s e q u a l to t e n m i c r o n s .

to

37

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38
PLATE

II

MEIOSIS IN T E T R A P L O ID SPINACIA O L E R A C E A L .
(all f i g u r e s f r o m T e t r a p l o i d A i n t e r sex)

1.

P ach y ten e.

2.

D ia k i n e s i s .

3.

M e ta p h a s e I - - A t l e a s t one t r i v a l e n t is c l e a r l y v i s i b l e in the
c e n t e r of th e g ro u p .

4.

A n a p h a s e I - - T h e tw e n t y - f o u r c h r o m o s o m e s a t e i t h e r p o le
c a n be a c c u r a t e l y co u n ted a t th i s s ta g e .
N ote the t h r e e
" l a g g i n g " c h r o m o s o m e s t h a t a p p e a r to r e m a i n on the m e t a ­
p h ase p la te .

5.

T e lo p h a s e I I - - T h i s show s th e n o r m a l tig h t g ro u p in g of c h r o ­
m o s o m e s a t the f o u r p o l e s .

6.

T e lo p h a s e I I - - T h e c h r o m o s o m e s a p p e a r to s p r e a d out f r o m
th e c o m p a c t g ro u p in g of M i d - te lo p h a s e II.

7.

C y to k in e s is s t i m u l a t i o n a f t e r T e lo p h a s e I I - - A f t e r th e T e l o ­
p h a s e II c h r o m o s o m e s s p r e a d out, i r r e g u l a r c y t o k in e s is
is in i tia te d .

8.

" P o l y a d s 1’- - The r e s u l t of the i r r e g u l a r c y t o k i n e s i s is the
f o r m a t i o n of m u l t i c e l l e d " t e t r a d s . "
T h e y v a r y in s iz e and
n u m b e r p e r p o lle n m o t h e r c e ll.

9.

P o l l e n - - T h e i r r e g u l a r - s i z e d p o ll e n g r a i n s r e s u l t f r o m the
ab n o rm a l " -te tra d s."
The s m a l l e r p o lle n g r a i n s s e e m s to
b e o p ti c a ll y vo id of s u b s t a n c e w hen s ta i n e d w ith a c e t o c a rm in e .

S c a le --O n e

d i v i s i o n i s e q u a l to t e n m i c r o n s .

39
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40
P L A T E III
M EIOTIC

CONFIGURATIONS IN SPINACIA O L E R A C E A L .

1.

M e ta p h a s e I - - ( T e t r a p l o i d A i n t e r se x ).
Shows p r e m a t u r e m i ­
g r a t i o n to w a r d th e p o l e s , o r p o s s i b l y u n iv a le n ts .

2.

A n a p h a s e I - - ( T e t r a p l o i d A i n t e r s e x ).
T h is s ta g e show s the
a c c u r a t e c o u n ts of th e tw e n t y - f o u r c h r o m o s o m e s , tw elv e
c h r o m o s o m e s a t e a c h p o le .

3.

A n a p h a s e I - - ( T e t r a p l o i d A i n t e r sex ).
Shows a c h r o m o s o m e
b r i d g e w h ich is c o m m o n in the t e t r a p l o i d .

4.

M e ta p h a s e I - - ( l i n e L - 1 5 i n t e r sex ).
The c h r o m o s o m e s a r e
s e p a r a t i n g p r i o r to th e m i g r a t i o n to th e p o l e s .
D ifferen ces
in th e r a t e of s e p a r a t i o n a r e n o te d , and c h r o m o s o m e s w ith
s u b m e d ia n k i n e t o c h o r e s c a n be id e n tif ie d .
T h e r e i s no v i s ­
ib le h e t e r o m o r p h i c c h r o m o s o m e p a i r .

5.

M e ta p h a s e I I - A n a p h a s e I I - - ( l i n e A - 10 m a le ) .

6.

M e ta p h a s e I - - ( l i n e L - 1 5 i n t e r s e x ) .
Shows no v i s i b l e h e t e r o ­
m o r p h i c p a i r , a n d a p p e a r s to be no d i f f e r e n t f r o m th e M e t a ­
p h a s e I of the lin e A - 10 m a le ( P la t e I, N o. 5).

7.

M e ta p h a s e I - - ( T e t r a p l o i d A i n t e r se x ).
T h is show s th e p r e s ­
e n c e of a t l e a s t two d i s t i n c t t r i v a l e n t s , in lin e on e i t h e r sid e
of the m e io ti c c o n f ig u r a tio n in th e c e n t e r c e ll.

8.

D ia k i n e s i s - - ( lin e A - 10 m a le ) .
F ro m th e ir c h a ra c te ristic
s h a p e s , th e c h r o m o s o m e s can b e id e n tif ie d a t th is s ta g e .

9.

D ia k in e s i s - - ( l i n e C - l i n t e r s e x ) .
T h is lin e i s d i f f e r e n t in
h a v in g on ly one n u c l e o l a r c h r o m o s o m e p a i r .

S c a le --O n e

d iv is io n i s e q u a l to te n m i c r o n s .

41

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G EN ETIC INVESTIGATIONS OF SEX EXPRESSION
IN SPIN A CIA

Review of L ite r a tu re

While w orking on the seed -ty p e in h e rita n c e of spinach,
N o h ara (1923) n o ted a n e a r - p e r f e c t 1:1 sex ra tio ; n am ely , 495
fe m a le to 496 m a le .
T hat the d iffe re n c e s in m ale types (e x tre m e and v e g e ta ­
tive) and m onoecious fo rm s a re due to genetic fa c to r s is in d i­
c a te d by the w ork of R osa (1925), who conducted e x p e rim e n ts
w hich showed th a t en v iro n m en tal in flu en ces did not have any
a p p re c ia b le influence on the se x e x p re s s io n of spinach.

He

te s te d r ic h v e r s u s p o o r s o ils , shade v e rs u s full lig ht, wide
v e r s u s c lo se spacin g, e a r ly v e rs u s la te plantin g, and m u tilatio n .
Of h is to ta l population of 5,198 p la n ts, he had 50.5 p e rc e n t
m a le , 49.3 p e r c e n t fe m a le , and 0.2 p e rc e n t in te rs e x .
H ir a ta and Y am am oto (1930) selfed in te rs e x e s of Spinacia
and g rew only fe m a le s and in te r s e x e s fro m them .

They c o n ­

cluded th a t the in te r sex es they d e a lt w ith w ere fe m a le -lik e ,
g e n e tic a lly .

43
N egodi (1934) in v e stig a te d sex in h e rita n c e in S. o le ra c e a ,
and su g g e s te d th a t sex w as c o n tro lle d by a m ultiple com plex of
g en es co n stitu tin g a sex u al group, the fem a le being hom ogam etic
and the m a le being h e te ro g a m e tic .

He su g g ested th a t the m o n o ­

ecio u s condition depended on d iffe re n c e s in the fem ale com plex,
and e ith e r would b r e e d tru e o r s e g re g a te into m onoecious and
fe m a le .

E n v iro n m en t w as c o n sid e re d to be a fa c to r in the d e ­

v elo p m en t of a c e r ta in type of m onoecious condition.

His schem e

w as of the type w h ere M M FF = fe m a le , MMFf = m ale, w ith F ^ ,
F ^ m o noecious f a c to r s .

MMFF^ = m onoecious, which s e g r e ­

g a te s 0.25 p e r c e n t M M FF being fem a le, 50 p e rc e n t MMFF^
being lik e the p a re n t, and 25 p e rc e n t MMF^F^ being tru e b r e e d ­
ing in te r sex.
MMF F
MMF F

1 1

= m onoecious which s e g re g a te s 25 p e rc e n t

being tr u e b reed in g in te r sex, 50 p e rc e n t M M F .F

1 2

bein g lik e the p a re n t, and 25 p e rc e n t M M F^F^ en v iro n m en tal
c o n tro lle d m o n o ecio u s, o r fe m a le .
M iry u ta (1937) d e te rm in e d th a t it w as quite p o ssib le to
obtain c o n sta n t fo rm s , p ro d u cin g fem a le and m onoecious p la n ts
in a 1:1 ra tio , w ith com p lete co n siste n c y of the m onoecious
type, as r e g a r d s sex c h a r a c te r s .

In the F ^ , it is p o s sib le to

44
o btain (1) m a le and m onoecious (near m ale p lan t), (2) a ll m ono­
e cio u s p la n ts w ith s e g re g a tio n into two m onoecious sub grou ps,
and (3) a ll m onoecious p la n ts w ithout seg reg atio n .

He su g g ested

th a t s e x typ es in £3. o le ra c e a a r e no t c o n tro lle d by en v iro n m en t,
b u t th a t they com e to fu ll developm ent only u nder c e r ta in e n ­
v iro n m e n ta l con d itio n s.
Sugimoto (1947) o ffered a g en etical explanation b a se d
upon an X-Y m e c h a n ism p lu s f a c to r s ZZ.
f a c to r s :

He had six ty p es of

(1) fe m a le f a c t o r - - ZZXX; (2) en v iro n m en tal fem a le

in te rm e d ia te --Z z X X ; (3) m ale fa c to r--z z X X ; (4) en v iro n m en tal
m ale in te rm e d ia te --Z z X Y ; (5) fem a le in te rs e x --z z X X ; and (6)
m a le in te r s e x - - ZZXY.
F ro m the tra n s la tio n of the p a p e r, th e re was no ap p a re n t
ex p lan atio n fo r the selfing of m a le -ty p e in te r sex p la n ts w hich
co n tain ed the XY fa c to r.

F r o m a m a th e m a tic a l view point, the

selfin g of an X-Y individual w ill r e s u lt in o n e -fo u rth of the
p ro g en y having a YY fa c to r .

E n v iro n m en t as a F a c to r

In the sp rin g of 1950, b efo re th is p r e s e n t w ork w as in i ­
tia te d , a t r i a l plan tin g of spinach, co n sistin g of two v a r ie tie s ,

45
w as planted, to ch eck an unpublished r e p o r t of an e x p e rim e n t
cond ucted by B o w se r (1943), indicating th a t spacing and date of
p la n tin g would influence the sex ra tio .

F ro m the r e s u lts of

th is t r i a l p lan tin g (Table XVI in the Appendix), it was concluded
th a t n e ith e r the spacing n o r the date of planting sig n ifican tly
in flu en ced the sex ra tio .
R osa (1925) po in ted out th a t thinning would often influence
the se x r a tio , owing to the s e le c tio n of the p la n ts being thinned
out.

The m ale p la n ts a re often the s m a lle s t a t the stage when

thinning is p r a c tic a l, and the tendency to rem ove the s m a lle s t
p la n ts (m o stly m ale) w ill cau se the rem ain in g population to be
p re d o m in a n tly fe m a le o r in te r sex.
An influence of date of planting on the sex ra tio m ay be
in d ic a te d u n le ss the p la n ts a r e all s c o re d a t the sam e age.

The

e a r l i e r p la n tin g s w ill often show an in c re a s e in the n u m b e r of
in te r s e x e s if c o m p a re d w ith la t e r plantin gs com posed of younger
p la n ts .

The in te r sex condition in sp ecific p la n ts w ill m a n ife st

its e lf to a g r e a t e r d eg re e as the p lan t m a tu re s .

This is tru e

only of p la n ts of a sp ecific g enetic m ak e-u p , a v e rs io n of Sugio m o to 's 1'e n v iro n m e n t in te rm e d ia te f a c to r ."

46
T able III co n tain s the to tal n u m b e rs of m ale, fe m a le , and
in te r se x p la n ts f ro m the t r i a l planting in 1950.
When th is w as b ro k en down by v a r ie tie s , the s trik in g
d iffe re n c e w as in the n u m b e r of in te rs e x e s in each v a r ie ty —
8.3 p e r c e n t, c o m p a re d to 1.9 p e rc e n t.

In asm uch as e n v iro n ­

m e n ta l cond itio ns w ere s im ila r fo r each v a rie ty , th is differen ce
m ay be a ttrib u te d to g enetic f a c to r s .

A p ro g ra m was in itia te d

to t e s t th is contention.

M a te ria ls and M ethods

In te r sex p la n ts which w ere o p en -p o llen ated w ere s e le c te d
fro m th is 1950 sp rin g planting, and a b reed in g p ro g ra m was i n i­
tia te d .

By u tiliz in g the g reen h o u se, fo u r com p lete g en eratio n s

w ere p ro d u c e d and ev alu ated .

In the w in ter of 1950-51, fifteen

p ro g e n ie s w ere grown; tw elve individuals fro m seven of th e se
p ro g e n ie s w ere s e le c te d and p la n ted in the fie ld in the sp rin g
of 1951.

In the w in te r of 1951-52, six p ro g e n ie s w ere grow n

fro m one c r o s s and five se lfs s e le c te d fro m the 1951 sp rin g
p la n tin g s.

In the sp rin g of 1952, fifty p ro g e n ie s w ere grow n

f ro m c r o s s e s and s e lfs of the m a te r ia l grow n in the w in ter of

47
T A B L E III
SEX EXPRESSION OF TWO VARIETIES OF SPINACH
(field planting)
T otal

M ale

F e m a le

In te rs e x

V a rie ty
No.

P e t.

No. P e t.

No. P e t.

No. P e t.

1,262

66.1

598 47.6

559 44.3

105

8.3

Nobel

648

33.9

310 47.8

326 50.3

12

1.9

T o tal

1,910

100.0

908 47.5

885 46.3

117

5.7

Long
Standing
B loom s dale

1951-52.

D ata fro m all p lan tin g s a re given in T ables XII,

XIII, XIV, XV, in the A ppendix.
In addition to c ro s s in g and selfing diploid p la n ts, the
u se of polyploidy w as to be included.

H ow ever, to date, only

two te tra p lo id p la n ts have been produced.

As yet, no c r o s s e s

have b een a tte m p te d , pending f u r th e r study of the sta b ility of
the te tra p lo id m a te r ia l as d e s c rib e d in the cytological study.

48
G enetic O b se rv a tio n s

F o r the m o s t p a r t, the d ata to be u sed in th is g e n e tic a l
d is c u s s io n have b een tak en fro m the sp rin g cro p grow n in 1952.
Spinach, b e c a u se of its anem ophilous n a tu re and its p re d o m in an tly
d io ecio u s condition, is e x tre m e ly h etero zy g o u s.

It h as t h e r e ­

fo re tak en fo u r g e n e ra tio n s of co n tro lle d b reed in g to obtain
lin e s w hich w ere p u re enough to show gen etical p a tte rn s of
in h e rita n c e .

This is d e m o n stra te d by the data c o lle c te d on the

c o lo r f a c to r (A), w hich has now been shown to follow a single
gene type of in h e rita n c e .

But it was not u n til the fo u rth g en ­

e r a tio n th a t th is could be shown to be tru e .
One c r it ic i s m

of the p re v io u sly p re s e n te d sch em es of

se x in h e rita n c e is th a t the a n a ly sis has b een w orked out fro m
d ata fro m a sm a ll n u m b e r of p la n ts, grow n fo r only a few g en ­
e r a tio n s .

Sex in h e rita n c e in spinach is obviously too com plex

to be ex p lain ed fro m such a sm a ll am ount of data.

The p r e s e n t

study, although m o re ex ten siv e than m ost, s till p ro v id e s data
su ita b le only fo r a g e n e ra l a n a ly sis .
In fo rm u la tin g a genetic schem e of sex in h e rita n c e , the
p r e s e n c e of an X-Y m e ch an ism has been assu m ed .

This is

p u re ly an assu m p tio n , b a s e d upon genetic data, and not fro m

49
c y to lo g ic a l o b s e rv a tio n s of 11sex c h ro m o s o m e s .11

As p re v io u s ly

m en tio n ed , tbe p r e s e n c e of a h e te ro m o rp h ic chro m osom e p a ir
h as n e v e r b e e n r e p o rte d in iS. o le ra c e a , n o r was the p re s e n c e
of such a p a i r d e te c te d in th is study.

H owever, as s ta te d b e ­

f o r e , th is is no t co n clu siv e evidence a g a in st the e x isten ce of a
p a i r of c h ro m o so m e s w hich a c t as " s e x c h ro m o s o m e s ."

It is

d iffic u lt to ex p lain the 1:1 sex ra tio w ithout such a m e ch an ism .
The p re s e n c e of m odifying sex genes lo c a te d on a c h r o ­
m o so m e s e p a ra te fro m the X and Y ch ro m o so m es was also
a s s u m e d , b a s e d on genetic d ata.
The th ir d assu m p tio n was the balancing of the m odifying
sex g enes by som e m e c h a n ism in o r d e r to m a in tain a 1:1 sex
ra tio u n d er n a tu ra l co ndition s.

C o m m ercia l v a rie tie s of spinach

have b e e n s e le c te d fo r m any y e a r s , to w ard the elim in atio n of
the e x tre m e m a le type and tow ard an in c re a s in g n u m b er of
in te r s e x p la n ts , u n til the m e ch an ism fo r co n tro l of the 1:1 sex
ra tio h as b een a lte r e d .

D ark G reen B loom sdale, Long Standing

B lo o m sd ale, J u lia n a , N obel, and H ollandia a re ex am p les of c o m ­
m e r c ia lly im p o rta n t v a r ie tie s th a t have o rig in a te d fro m single
p la n t s e le c tio n s of in te r sex p la n ts .

Even though th e se v a r ie tie s

have had th is m e c h a n ism a lte r e d during th e ir o rig in atio n ,

50
n e v e r th e le s s , they s till p re d o m in an tly m a in ta in the 1:1 sex
r a tio .

The co m p lete a lte ra tio n of th is m e ch an ism has b een a c ­

c o m p lish e d only re c e n tly by the e s ta b lis h m e n t of p u re -b re e d in g
in te r se x lin e s .
A p ro b le m of m a jo r im p o rtan ce is the p lacin g of sex
ty p e s into c la s s e s .

F e m a le s , m a le s , and e x tre m e m ale types

a re quite d is tin c t in th e ir m orphology, and a re e a s ily reco g n ized .
H ow ever, the v a rio u s d e g re e s of in te r sex p la n ts p r e s e n t a d if­
f e r e n t situ a tio n .

To p la c e the in te r sex p la n ts into a single

c la s s ific a tio n m ak es the genetic in te rp re ta tio n difficu lt, and it
is a lso d ifficu lt to d e te rm in e the p ro p e r c la s s ific a tio n fo r the
v ary in g d e g re e of in te r s e x o r to d e te rm in e the extent of e n ­
v iro n m e n ta l influence on the in te r sex condition.

By sc o rin g the

se x type of the p la n ts a t a p p ro x im ately the sam e stage of d e ­
velo p m en t, the v ary in g en v iro n m en tal in fluen ces a re held to a
m inim u m .

In th is study, seven c la ss ific a tio n s fo r sex type have

b een d e sig n a te d .

P la n t ty p e s .
1.

F e m a le - - A t an e a rly stag e, flow er developm ent is

c h a r a c te r iz e d by long s tig m a s, and as the p la n t m a tu re s and
p o llen is av ailab le to b rin g about fe rtiliz a tio n , the ra p id

51
d ev elo p m en t of s e e d ta k e s p la c e .

P o in ts to check a re the t e r ­

m in a l ends of the l a t e r a l b ra n c h e s and the b a se of the m ain
flo w e r sta lk .
e rs

It is in th e se a r e a s w here h e rm a p h ro d itic flo w ­

a p p e a r, if the p la n t is a fem ale in te r sex.
2.

F e m a le in te r s e x --T h e p lan t, if young, m ay

p a s s as

fe m a le , but as it a p p ro a c h e s m a tu rity , ap p ro x im ately 30 p e r c e n t
of the flo w e rs a r e e ith e r h e rm a p h ro d itic o r an d ro ecio u s.

The

g r e a te s t c o n c e n tra tio n s of th e se flo w e rs a re u su ally n e a r the
te rm in a ls of the flo w er s ta lk s .
3.

In te r s e x - - This type of p la n t p ro d u ces m ain ly a n d ro ­

ecio u s and gynoecious flo w e rs in a p p ro x im ately equal n u m b e rs ,
w ith a s m a lle r n u m b er of h e rm a p h ro d itic flo w e rs .

The i n t e r ­

s e x e x p re s s io n is v is ib le w ith the f i r s t flo w er c lu s te r s .
4.

M ale i n t e r s e x - - This type is iden tified by having a

m a jo rity of a n d ro ecio u s flo w e rs.

In e x tre m e s of th is

a few fu n ctio n al o v a rie s a r e p re s e n t.

type only

T hese a re u su ally found

n e a r the c e n tr a l p o rtio n of the m ain flow er stalk .
5.

N onfunctional m ale in te r s e x --T h is type m ay e a s ily be

s c o re d as p u re m a le , as no fun ctio nal o v a rie s a r e p r e s e n t.
a p p a re n tly an d ro e c io u s flo w er buds, sm all h a ir- lik e

stig m as

p ro tru d e fro m the c e n te r of the flo w er b efo re the stam en

In

52
fila m e n ts elo n g ate.

The n u m b er of th e se nonfunctional h e rm a p h ­

ro d ite flo w e rs is u su a lly few, and they can e a s ily be m is s e d .
C a re m u s t be ta k en not to confuse the w ith e re d stam en f i l a ­
m e n ts of old flo w e rs f o r s tig m a s, as th e re is a c lo se r e s e m ­
b la n ce betw een the two.

This type of p la n t is m o rp h o lo g ically

m a le in a p p e a ra n c e , being s m a lle r and m a tu rin g e a r l i e r than
f e m a le s o r fu n ctio n al in te r se x e s.

It is p o ssib le th a t the gyno-

ecio u s e x p re s s io n in th is type of p la n t is co m p arab le to the
an d ro e c io u s e x p re s s io n in the stro n g fem ale in te rs e x , except
th a t in red u cin g the an d ro ecio u s e x p re ssio n , it is the n u m b er
of a n th e rs w hich a r e red u ced , and in the c a se of the gynoecious
e x p re s s io n the o v ary b eco m es red u ced to a nonfunctional body.
H ow ever, one fu n ctio n al a n th e r m ay produce enough p o llen to
f e r tiliz e a g r e a t n u m b e r of gynoecious flo w e rs.
6.

V eg etative m a le -- T h e flo w ers on th is type a re p u re ly

a n d ro e c io u s, and the p la n t re s e m b le s the nonfunctional m ale
in te r sex type.
7.

E x tre m e m a le - - T h is type is m o rp h o lo g ically d iffe re n t

in th a t it flo w e rs e a rly , seldom b ra n c h e s , and m a tu re s and d ies
e a rly .

The flo w e rs a r e a ll an d ro ecio u s.

H ow ever, th e re have

b een h e rm a p h ro d itic flo w e rs noted on the e x tre m e m a le-ty p e

53
P L A T E IV
SEX T Y PE S IN SPINA CIA O L E R A C E A L .

1.

E x tr e m e m a le ty p e - - T h e flo w e rs a r e a ll a n d r o e c io u s .
The
s ta m e n f ila m e n ts , a f t e r the a n th e r s h av e d e h is c e d and d r ie d
up, m a y g iv e th e a p p e a ra n c e of s tig m a s .

2.

M ale i n t e r s e x - - N o te th e h o r n e d - ty p e s e e d s , w h ich a r e l i m ­
ite d to one o r two p e r flo w e r c l u s t e r .

3.

I n te r s e x - - A n d r o e c io u s an d g y n o e c io u s f lo w e r s a r e
e q u a l in n u m b e r th ro u g h o u t the p la n t.

4.

F e m a le in t e r s e x - - The p la n t w as p r e d o m in a n tly g y n o e c io u s,
b u t the te r m i n a l b r a n c h e s a s show n h e r e r e v e r t e d to th e
a n d ro e c io u s c o n d itio n .

5.

F e m a l e - - T h e f lo w e r s a r e
th e s tig m a s .

ab o u t

a ll g y n o e c io u s; n o te the le n g th of

T h e s e f ig u r e s a ls o in d ic a te th a t flo w e r c l u s t e r s c o n ta in in g g y n o ­
e c io u s f lo w e r s a r e m o re a p t to be a c c o m p a n ie d b y s m a ll le a v e s
th a n flo w e r c l u s t e r s c o n ta in in g a n d r o e c io u s f lo w e r s .

54

55
p la n t in c e r ta in fo re ig n s tr a in s of spinach grow n h e re a t this
sta tio n .

F lo w e r ty p e s .

Seven flow er types w hich show five i n t e r ­

g ra d a tio n s f ro m gynoecious to an d ro ecio u s flo w e rs a re in d icate d
by sev en d raw ings in F ig u re B.

The draw ings w ere m ade fro m

flo w e rs w hich w ere d is s e c te d fro m a single fem ale in te r s e x
flo w e r stalk .

V isually , m o rp h o lo g ically p is tilla te flo w ers (Type

1) a re c h a r a c te r iz e d by th e ir lo n g -b ra n c h e d stig m a s, the length
of w hich v a r ie s c o n sid e ra b ly among d iffe re n t p la n ts .

The o v ary

is la rg e and in c r e a s e s in size as soon as f e r tiliz a tio n ta k e s
p la c e .

P e r f e c t (Type 2) is a weak an d ro ecio u s type flo w er, b u t

the sin g le a n th e r p ro d u ced is functional, producing a c o n sid e ra b le
am ount of p o llen .

The ap p earan ce of the an th er u su a lly is

la te , and often the flow er h as b een f e r tiliz e d b efo re the included
a n th e r m a tu r e s .

P e r f e c t (Type 3) is functional fo r both p a r ts .

The n u m b e r of b ra n c h e s of the stig m a is u su a lly redu ced, but
the o v a ry is s till la rg e .
the a n th e r s .

O ften sm a ll b r a c ts a re fo rm ed n e a r

P e r f e c t (Type 4) is often fun ctionally stam in ate

only, as the o v a ry is c o n sid e ra b ly red uced , and often a b o rts ,
r a th e r than fo rm in g n o rm a l seed.

The naked seed (ovule) often

grow s out of the o v ary , and is not f e r tile .

Types 5 and 6 a re

FIGURE B
FLOWER TYPES

V isually m o rp h o lo g ically p is tilla te (Type 1).
P e r f e c t (Type 2).
P e r f e c t (Type 3).
P e r f e c t (Type 4).
F u n c tio n a lly stam in ate (Type 5).
F u n c tio n a lly stam in ate (Type 6).
V isu ally m o rp h o lo g ically p is tilla te (Type 7).

57
fu n c tio n a lly s ta m in a te flo w e rs .

R u d im en tary stig m as a re fo rm e d

and m ay be b ra n c h e d and extend beyond the a n th e rs , o r m ay be
a sin g le h a ir - lik e

s tr u c tu re w hich extends beyond the a n th e rs

only, w hile th ey a r e in the bud stag e.

T hese types of flo w e rs

a re often co nfused w ith p u re an d ro ecio u s flo w e rs which have
m a tu re d th e ir a n th e rs .

The stam en fila m e n ts sh rin k in size

and the a n th e r w all fa lls off, giving the ap p earan ce of s tig m a ­
lik e s tr u c t u r e s .

The bud stage is the b e s t tim e to exam ine

f o r fu n ctio n ally sta m in a te flo w e rs.

V isually m o rph olo gically

s ta m in a te flo w e rs (Type 7) u su a lly contain fo u r a n th e rs , but
th is n u m b e r is not co n stan t.

O ccasio n ally , a fte r the flow er has

m a tu re d and the stam en fila m e n ts have shrunk to the size of
s tig m a -lik e s tr u c tu r e s , the la rg e b ra c ts w ill fold upw ard and
can give an a p p ea ra n ce s im ila r to th a t of a p is tilla te flo w er.
Only by using such a sy ste m of c la s s ific a tio n can the
m i nimum

n u m b e r of f a c to rs re q u ire d to fit a genotype to the

v a rio u s c la s s e s be d e te rm in e d .
The ZZXY s y ste m , as p ro p o sed by Sugiomoto (1947), is
b a s e d upon a schem e s im ila r to the type u se d h e re , but his is
lim ite d in the n u m b er of c la s s e s to which his fa c to rs w ill fit;

58
ho w ever, h is te r m

' 1en v iro n m en tal in te rm e d ia te " allow s the in ­

c lu sio n of s e v e r a l d e s c rib e d ty p e s.
A sch em e b a s e d upon c ro s s in g o v er betw een the X and
Y c h ro m o s o m e s, w hich p e r m its varying am ounts of each sex d e te rm in in g ch ro m o so m e to be included, adapts v e ry w ell to the
v a ry in g d eg re e of the in te r s e x condition, and to the se g re g a tio n
of e ith e r fe m a le s o r m a le s , but b re a k s down when selfed i n t e r ­
se x p la n ts s e g re g a te into m a le s and fe m a le s w ith o r w ithout the
in te r s e x condition also se g re g a tin g .
F ro m data obtained w ith the b reed in g m a te ria l of spinach
u se d in th is study, an accep tab le g en etical schem e fo r sex in ­
h e rita n c e m u s t explain:
1.

C on stan t 1:1 sex ra tio .

2.

P ro d u c tio n of in te r sex es of d iffe re n t d e g re e s .

3.

M aintenance of a p u re -b re e d in g in te r sex line.

4.

S eg reg atio n of in te rs e x e s into (a) m a le s, fe m a le s ,

and in te r s e x e s ; (b) fe m a le s and in te r sexes only; o r (c) m a les
and in te r sex es only.
5.

P u re

s e x - in te r s e x c r o s s e s of d iffe re n t ty p e s.

59
G enetic E xplanation

The g en etic sch em e d ev ised to fit the conditions of the
o b s e rv e d r e s u lts of the b reed in g m a te r ia l is shown d ia g ra m a tic a lly
in F ig u re C.

It h as been a rra n g e d in a m odified P u n n ett sq u are

to show the g a m e te s and the re s u ltin g genotype of the in d iv id u als,
and by keying out to the m a rg in it shows the g am etes p ro duced
by e ac h type of individual, a ssu m in g com plete linkage of the
A-G g en es.

The A and G genes a re the a n d ro e c io u s- and

g y n o e c io u s-d e te rm in in g genes.
By a ssu m in g a v e ry low c ro s s o v e r value, n e a rly c o m ­
p le te coupling linkage of the A-G genes, then the g r e a t m a jo rity
of genotypes p ro d u ced would be as r e p re s e n te d by the eight
c o r n e r s q u a re s of the XX and XY b lo c k s.

This sy ste m w ill

then m a in ta in a 1:1 ra tio fo r sex.
In o r d e r to p ro d u ce the in te rs e x condition th e re m u st
be c ro s s in g o v er betw een the A -G genes, and this m u s t n a tu ra lly
o ccu r in in d iv id u als of the (Aa Gg) type.

This condition also

re d u c e s the ch an ces fo r the fo rm a tio n of in te r s e x p la n ts, as
c ro s s in g o v e r in the (AA GG) o r (aa gg) individuals w ill not
a l te r the genotype of the g am etes produced.

In fa c t, it m ight

be p o s sib le to have the A-G genes p r e s e n t in only the r e c e s s iv e ,

E X PL A N A T IO N F O R FIG U R E C

The XX b lo c k a n d th e YY b lo c k s e g r e g a te only two ty p e s
of g a m e te s , w hile th e XY b lo c k s e g r e g a te s fo u r ty p e s of g a m e te
a s in d ic a te d in th e m a r g in s .

In a ll c a s e s th e A -G g e n e s a r e

a s s u m e d to b e lin k e d w ith a v e r y low c r o s s o v e r v a lu e .

How ­

e v e r , th e y a r e in d e p e n d e n t of th e X o r Y c h r o m o s o m e s .
AA. > Aa > a a , f o r a n d ro e c io u s te n d e n c ie s , and lik e w is e ,
GG > Gg > gg, fo r g y n o ecio u s te n d e n c ie s .

61
F IG U R E C
DIAGRAMATIC SCHEME FOR THE GENETIC EXPLANATION
FOR SEX INHERITANCE IN SPINACIA

G am ete s

X
A-G

v
A
A -g

X
a-G

X
a -g

X
A-G

X
A -g

X
a -G

X
a -g

XX
AA GG

XX
AA Gg

XX
Aa GG

XX
Aa Gg

XX
AA Gg

XX
AA gg

XX
Aa Gg

XX
Aa gg
*

XX
Aa GG

XX
Aa Gg

XX
aa GG

XX
aa Gg

XX
Aa Gg

XX
Aa gg
*

XX
aa Gg

XX
aa gg

* D e n o te s e n v ir o n m e n ta lly u n s ta b le in te r s e x ty p e s.

62
F I G U R E C (C o n tin u e d )

G am etes

X
A-G

X
A -g

X
a-G

X
a -g

G am etes

X
A -G

X
A -g

X
a-G

X
a -g

XY
AA GG

XY
AA Gg

XY
Aa GG

XY
Aa Gg

XY
AA Gg

XY
AA gg

XY
Aa Gg

XY
Aa gg

XY
Aa GG

XY
Aa Gg

XY
aa GG

XY
aa Gg
*

XY
Aa Gg

XY
Aa gg

XY
aa Gg
*

XY
aa gg

Y
A-G

Y
A -g

Y
a-G

Y
a -g

G am ete s

I

A-G

V
"
JL

A -g

V
X

a-G

Y
a-g

Game te s

* D e n o te s e n v ir o n m e n ta lly u n s ta b le in te r s e x ty p e s .

63
F I G U R E C (C o n tin u e d )

G am etes

Y
A-G

Y
A -g

Y
a-G

Y
a -g

v
X

YY
AA GG

YY
AA Gg

YY
Aa GG
*

YY
Aa Gg

YY
AA Gg

YY
AA gg

YY
A a Gg

YY
Aa gg

YY
Aa GG
*

YY
Aa Gg

YY
aa GG

YY
aa Gg
*

YY
Aa Gg

YY
Aa gg

YY
aa Gg
*

YY
aa gg

A-G

v
i

A -g

I

a-G

I

a -g

* D enotes en v iro n m en tally u n stab le in te r sex ty p es.

64
o r d om inant condition in the population, which, would elim in ate
the p o s s ib ility of the p ro d u ctio n of in te rs e x e s , and m ain tain a
c o n sta n t 1:1 sex ra tio .
A ssu m in g som e c ro s s in g o v er does take p la ce (all h o ­
m ologous c h ro m o so m e p a ir s w ere o b serv ed to show c h ia sm a ta
fo rm a tio n during m e io s is in S. o le ra c e a ) , the f i r s t step is the
p ro d u c tio n of p u r e - s e x individuals w hich w ill produce g am etes
which, when com bined, w ill give a la rg e p ro p o rtio n of in te rs e x
ty p e s, o r it is p o s sib le to p ro d u ce in te r s e x types d ire c tly as
the r e s u lt of the c r o s s in g -o v e r .

F o r exam ple, the individual

(XX Aa Gg) w ill, as a r e s u lt of c ro s s in g o v er, produce g am etes
of the (X A-g) and X a-G) type.

These g am etes com bined

w ith Y -contain in g g am etes w ill produ ce m a les of the type
(XY A- g -), o r m a le in te rs e x e s of the type XY a - G -), and
if com bined w ith X -con tain ing g am etes they w ill be r e v e r s e d
in th e ir actio n and p ro d u ce fe m a le s of the (XX a - G-) type,
o r fe m a le in te r s e x e s of the type (XX A- g -).
The fe m a le in te rs e x e s p ro duced in th is m a n n er would
a lso be of two ty p e s.

The " s tr o n g e s t" in te r sex of the type

(XX AA Gg) would, when selfed , se g re g a te into fe m a le s, the
p a te r n a l type, and into the p u re -b re e d in g in te r sex type, in the

65
ra tio of 1:2:1.

The o th e r fem ale in te r sex of the type (XX Aa

gg) would be a stro n g fe m a le in te rs e x , su b ject to en v iro n m en tal
in flu en ces to a g r e a te r extent, and would also s e g re g a te , when
se lfe d , into fe m a le s , the p a re n ta l type, and into the p u r e - b r e e d ­
ing in te r s e x type in the ra tio of 1:2:1.
To m e e t the conditions of the se g re g a tio n of se lfe d in ­
t e r s e x p la n ts into m a le s , as w ell as fe m a le s and in te r sex ty p es,
the YY type of individual was c o n sid e re d to be viable, and to
develop n o rm a lly .
F ro m the cyto lo g ical study w here the twelve ch ro m o so m es
w ere of six m o rp h o lo g ically id e n tic a l p a ir s , it would seem p la u s ­
ib le th a t th e re w ere no g r e a t d iffe re n c e s betw een the c h ro m o ­
so m es m aking up the X-Y m ech an ism .

It would also then seem

p la u sib le th a t the e x isten ce of a YY individual th a t would d iffer
only in its d e g re e of sex e x p re s s io n would be p o s sib le .
g e n e tic a l data b e a r th is out, as w ill be shown.

The

A ssum ing this

condition to e x ist, the XY m ale in te r sex p lan ts w ill then s e g r e ­
gate w hen se lfe d into fe m a le s , the p a re n ta l type, o th e r in te r sex
ty p e s, and m a le s , depending upon the genotype of the p a re n t
in te r sex.

66
In the c a se w h ere only m a le s and m ale in te rs e x e s s e g ­
re g a te fro m a se lfe d m ale in te r sex, the absence of the X c h r o ­
m osom e m u s t be a ssu m e d .

In o th e r w o rd s, the m ale in te rs e x

w as of the YY type.
F ro m the g e n e tic a l schem e involving the X-Y m ech an ism
and the A-G m odifying g enes, th e re a re tw en ty -sev en genotypes
(or th irty , counting linkage p a tte rn s ) re p re s e n tin g six phenotypes.
They a r e as follow s:
I.

M ales (pure b re e d in g , en v iro n m en tally stab le).
(XY AA GG)
(XY Aa Gg)
(XY aa gg)

(A-G, a -g linked)

(YY AA GG)
(YY Aa Gg)
(YY aa gg)

(A-G, a -g linked)

Note:
The YY m a les a re uncom m on, being the r e s u lt
of selfed XY in te rs e x p la n ts, o r such in te r s e x p la n ts
o u tc ro s s e d to XY m a le s , and the YY m a le s w ill in
tu rn p ro d u ce only m a les when c r o s s e d to fem ale
p la n ts .
II.

M ales (se g re g a tin g , en v iro n m en tally stable).
(XY
(XY
(XY
(XY

AA
Aa
AA
Aa

gg)
gg)
Gg)
Gg)

(A-g, a-G linked)

67
(YY
(YY
(YY
(YY

AA
Aa
AA
Aa

gg)
gg)
Gg)
Gg)

(A-g, a-G linked)

Note:
This type of YY m ale, when c r o s s e d to fem ale
p la n ts , w ill give Type II XY m a les and XY in te r s e x
p la n ts .
III.

N onfunctional m ale in te rs e x (seg reg atin g , e n v iro n ­
m e n ta lly influenced to produce seed).
(YY Aa GG)
(YY aa Gg)

IV.

M ale in te r s e x (seg reg atin g , en v iro n m en tally u nstable).
(XY Aa GG)
(XY aa Gg)

V.

M ale in te r s e x (pure b reed in g , f a ir d eg ree of e n v iro n ­
m e n tal sta b ility ).
(YY aa GG)

VI.

In te rs e x (seg reg atin g , high d eg ree of env iro n m en tal
s ta b ility ).
(XY aa GG)

VII.

In te rs e x (pure b reed in g , en v iro n m en tally stab le).
(XX AA gg)

VIII.

F e m a le in te r s e x (seg reg atin g , en v iro n m en tally u n stab le).
(XX Aa gg)
(XX AA Gg)

68
XX.

F e m a le (se g re g a tin g , en v iro n m en tally stab le).
(XX
(XX
(XX
(XX

X.

Aa
aa
Aa
aa

GG)
GG)
Gg)
Gg)

(A-g,

a-G linked)

F e m a le (pure b reed in g , en v iro n m en tally stable).
(XX AA GG)
(XX Aa Gg)
(XX aa gg)

(A-G,

a -g linked)

The six phenotypes r e p re s e n te d and iden tifiab le, b a r r in g
e n v iro n m e n ta l in flu en ces, a re m a le s, nonfunctional m ale i n t e r ­
s e x e s , m ale in te r s e x e s , in te r s e x e s , fem ale in te r s e x e s , and f e ­
m a le s .
The m o rp h o lo g ically e x tre m e m ale is no d ifferen t in sex
fro m the v eg etativ e m a le s.
The com plete data fo r all p lantin gs a re included in the
A ppendix, and only sp ecific c a s e s w ill be used h e re to illu s tr a te
p a r ti c u la r m odes of in h e rita n c e .
The fo rm a tio n of a p u re -b re e d in g in te r s e x line is b e s t
shown by the p ro g en y of the ten selfed in te rs e x p la n ts of the
p e d ig re e ( X F - 14-11 -15) which w ere grown in the sp rin g of
1952.
The XF p la n t w as a m ale in te rs e x type s e le c te d fro m
a p lan tin g of Long Standing B loom sdale grown in the sp rin g of

69
1950.

T h is p la n t w as o p en -p o llin ated , but was selfed to a high d eg ree

by the heavy p ro d u c tio n of an d ro ecio u s flo w e rs.

In the green h o u se in

1950-51, its p ro g en y s e g re g a te d into six m a le , fo u r fem a le, and fou r
in te r s e x p la n ts .
the fie ld in 1951.

The fo u r in te rs e x p lan ts w ere selfed and p lan ted in
L ine (X F-14-11), which was the pro gen y of one of

th e se in te r s e x lin e s , s e g re g a te d into th re e m a le, th re e fe m a le , eight
fe m a le in te r s e x , tw enty-one in te r s e x , and tw elve m ale in te rs e x p la n ts .
Two in te r s e x p la n ts w ere s e le c te d fro m th is progeny, selfed, and grow n
in the g reen h o u se in 1951-52.

F ro m the pro geny of one of th e se p la n ts

( X F -14-11 - 15), ten in te r s e x p la n ts w ere se lfe d and p lan ted in the field
in 1952.

The p a tte r n of se g re g a tio n of th ese is shown in Table IV.

It is quite obvious th a t th is p a r tic u la r line is b reeding
tru e f o r the in te r s e x condition.

The v a ria tio n s noted a re p ro b ­

ably due to en v iro n m en tal in fluen ces on the ra te of m a tu ratio n
of the p la n ts , and to som e slig h t e r r o r in sco rin g .

The geno­

type of th is lin e m ay be c o n sid e re d as being (XX AA gg), and
should re m a in as a tru e b reed in g line fo r the in te r s e x condition.
E x am p les of selfed in te rs e x p la n ts seg reg atin g into f e ­
m a le s and in te r sex es a r e in d icated by the data fo r four p ro g e n ie s
shown in T able V.

One line was grown during the sp rin g of 1951,

and th r e e , during the sp rin g of 1952.

70
T A B L E IV
PU R E-B R EED IN G INTERSEX TYPE (XX AA gg)

P e d ig r e e No.

Male
In te rs e x

In te rs e x

F e m a le
In te rs e x

(X F- 1 4 -1 1- 15- I)

1

45

3

(XF -1 4 -1 1 -1 5 -2 )

10

68

-

(XF -1 4 -1 1 -1 5 -3 )

7

33

1

(XF - 14-11- 15-4)

2

55

1

(XF - 1 4-11-1 5-5 )

20

56

2

(XF -1 4 -1 1 -1 5 -6 )

-

no

2

(XF - 14-1 1-15-7)

3

73

4

(XF - 14-11 -15 -8)

3

53

5

(XF - 1 4-11-15-9)

20

36

1

(XF - 14-11-15-18)

14

36

-

71
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72
N u m b er (X F -14-9) was in the second g en eratio n of se lfing, and p ro b a b ly was s till h etero zy g o u s to a high d eg ree, but
show ed the p a tte r n to w ard fem a le and in te r s e x ty p es.
F o r n u m b e r ( X F -14-11-7-22) the 1:2:1 ra tio fits the
d a ta giving a c h i-s q u a r e value of 0.981 and a P value of 0.65.
The genotype fittin g th is c a se would be (XX Aa gg), which s e g ­
re g a te d 1 (XX AA gg) : 2 (XX Aa gg), which a re both in te rs e x e s ,
and 1 (XX aa gg), w hich is fem a le.

The d ifferen c es in types

of in te r s e x e s again m ay be a ttrib u te d to en v iro n m en t and sco rin g .
The im p o rta n t fa c to r , how ever, is th a t h e re a re th re e in te rs e x
ty p es to one fe m a le type.
N um ber ( X F - 14-12-8-36) is a p oor 3:1 fit, but the g e n e ra l
p a tte rn is th e re .

In n u m b er (X F -14-12-8-37), the c h i-s q u a re

value f o r a 3:1 ra tio of in te rs e x types to fe m a le s is 0.442, and
a P value of 0.50, and the sam e genotype would fit as in the
c a s e w ith n u m b e r ( X F - 14-11 -7-2 2).
C a se s of selfed in te r s e x p lan ts seg reg atin g into m a le s
and in te r s e x ty p es a re

shown fro m the progeny seg reg atio n of

two in te r s e x p la n ts in Table VI.

N um ber (X F -14-12) fits a

3:1, w ith a c h i-s q u a re value of 0.785 and a P value of 0.40 fo r
the ra tio of one m ale to th re e in te r sex -ty p e p la n ts.

73
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74
The genotype of (YY aa Gg) s e g re g a te s into 1 (YY aa gg)
m a le , 2 (YY a a Gg) p a re n ta l-ty p e in te rs e x , and 1 (YY aa GG),
w hich is c o n s id e re d a s a stro n g m ale in te r s e x type.
The second exam ple of th is type a p p e a rs to be b reed in g
tr u e f o r the m ale in te r s e x type, allow ing fo r env iro n m en tal and
sc o rin g v a ria tio n s .

The genotype (YY aa GG) would s a tisfy the

r e q u ire m e n ts in th is c a s e .
F u r th e r evidence fo r the XY in te rs e x and YY-type in d i­
v id u a ls is shown in the data fro m line [(X F-3-2) x (X F -3 -2 )]-l,
w hich w as a b r o t h e r - s i s t e r c r o s s , w ith in te r s e x p la n ts fro m th is
p ro g en y being selfed, and th e ir progeny grow n in the field in
1952.
The individual (X F-3-2) was an in te r s e x p la n t se le c te d
f ro m a se g re g a tin g population of seventeen m a le s, nine fe m a le s ,
and two in te r s e x p la n ts .

The progeny fro m the selfing of this

p la n t w as grow n in the fie ld in 1951.

It s e g re g a te d into fo rty -

one m a le s , tw elve in te r sex es, and tw enty-tw o fe m a le s .
The th e o re tic a l r a tio fo r the seg reg atio n of an (XY aa
Gg) in te r s e x would be fo u r fe m a le , th re e m a le, th re e nonfunctional
m ale in te rs e x , fo u r p a r e n ta l type, and two in te r s e x .

If we

group the m a le s and m ale in te rs e x , including p a re n ta l type,

75
into the m a le c la s s , then a ra tio of fo u r fe m a le , two in te rs e x ,
and te n m a le p la n ts is expected.
T h is grouping of m ale in te r sexes w ith m a le s , including
the p a r e n ta l typ e, is su g g ested b ecau se of the influence e n v iro n ­
m e n t has on se x e x p re s s io n of the in te r s e x e s .

O b se rv a tio n s

in d icate th a t in g reen h o u se g e n e ra tio n s, the an d ro ecio u s e x p r e s ­
sion is delayed , w hile the gynoecious e x p re s s io n p e r s is ts .

It

w as th en p o s sib le to have a m a le -ty p e in te r s e x e x p re s s its e lf
and s e t a la r g e am ount of seed, while the sam e genotype in the
fie ld could p o s s ib ly be s c o re d as a m ale o r nonfunctional m ale
in te r s e x .
The ra tio of 4:2:10 fits the data, w ith a c h i-s q u a re value
of 1.971 and a P value of 0.40.
U nfo rtu n ately , the seg reg atio n of the prog eny fro m th is
c r o s s , w hich w as grow n in the g reen h o u se, was not obtained
b e c a u se the p la n ts w ere sc o re d and rem oved b efo re the com plete
e x p re s s io n of th e ir sex was m a n ifested .

H owever, fro m this

p ro g en y , elev en in te r s e x p lan ts w ere selfed and th e ir progeny
grow n in the fie ld in 1952.

By grouping the m a le s and no n­

fu n ctio n al m a le in te rs e x e s into one c la s s , the rem ain in g in te r s e x

76
ty p es into a n o th e r c la s s , and fe m a le s in the th ird c la s s , the
follow ing r a tio s w ere obtained, and a r e shown in T able VII.
C o n sid erin g only the XY seg reg atio n , and assu m ing the
m odifying g en es to be stro n g ly an d ro ecio u s, the expected d i s t r i ­
bution is 1 XX : 2 XY : 1 YY, o r one fem ale to th re e m ale o r
in te r s e x .

T his 3:1 ra tio

s q u a re and P v alu es a r e

was applied to the data, and the ch iindicated in Table VII.

The se g re g a tio n of m a le s and in te r s e x types was not
quite a s co n clu siv e, but h e re again the sex balance was a p p ro a c h ­
ing e q u ality and was su b ject to env ironm ental influences to a
g r e a t e r d e g re e .

H ow ever, p la n ts (by using the l a s t num ber in

the p e d ig re e to d esig n ate plants) n u m b e re d 47 and 49,

w ith the

high p ro p o rtio n of in te r se x e s, a re pro b ab ly of the genotype
a a GG), w hich s e g re g a te s one fem ale to th re e in te rs e x .

(XY

A lso,

p la n ts n u m b e re d 43, 44, 45, 46, and 48 a p p ea r to be f a ir ly
stro n g fo r the in te r s e x condition, and a r e p ro b ab ly of the geno­
type (XY aa Gg).

The rem ain in g fo u r p la n ts, n um bered 40, 41,

42, and 50, a p p e a r to be stro n g ly m ale, and a re p ro b ab ly of the
genotype (XY Aa GG).

77

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VII (Continued)

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79
T h is follow s the p a tte r n of p ro d u ctio n of th e se ty p es,
w hich a r e p ro d u c e d in the ra tio of 2:1:2; th a t is 2 (XY Aa GG)
: 1 (XY a a GG) : 2 (XY aa Gg).
I.

The C ro s s B etw een In te rs e x and Strong M ale.

stro n g m a le w as tak en fro m an in c re a s e planting of a fo re ig n
p la n t in tro d u c tio n population (F .P .I. 164965).

The plan t was of

the m o rp h o lo g ically e x tre m e m ale type.
T his c r o s s was acc o m p lish ed in the green h o u se in 195152, as w ere the o th e r c r o s s e s .

As stated b e fo re , the andro ecio u s

condition is s u p p re s s e d o r delayed in greenho use planting, and
b e c a u se of th is condition the in te rs e x p la n t had p ro duced no
an d ro e c io u s flo w e rs , bu t was in a full gynoecious bloom .

These

gynoecious flo w ers w ere p o llin ated with pollen fro m the e x tre m e
m a le p la n t and the seed had s e t b efo re any and roeciou s flo w ers
a p p e a re d .

The p la n t w as then p ru n ed back, leaving only the

p o rtio n of the ste m s b e a rin g fe rtiliz e d seed s.

The andro ecious

flo w ers then a p p e a re d , but as no m o re gynoecious flo w ers d e ­
veloped, th e re was no dan ger of producing selfed seed.
p ro g en y b o re th is out by using o th e r fa c to rs as c o n tro ls .

The
In

th is c a s e it w as the h o rn e d -s e e d condition w hich was dom inant,
and the m ale p la n t w as hom ozygous fo r th is dom inant c h a ra c te r,

The

80
th u s, a ll s e e d -b e a rin g p la n ts in the p ro g en y e x p re s s e d th is
h o rn e d c h a r a c te r .
The r e s u lts of th is c r o s s as to sex e x p re ssio n w ere
th irty -n in e m o rp h o lo g ically e x tre m e m a le s, tw e n ty -th re e i n t e r ­
s e x e s , and six te e n fe m a le in te r s e x e s .
m a le to one in te rs e x .

This is a p e r f e c t one

The genotype of the m ale w as pro b ab ly

(XY Aa Gg), w ith A -G and a -g linked.
could have b een (XX AA gg).

The in te rs e x genotype

This c r o s s would then se g re g a te

1 (XY AA Gg) : 1 (XY Aa gg), both being m a le s, and 1 (XX
AA gg) in te r s e x : 1 (XX Aa gg), which should show the fem ale
in te r s e x condition.
II.
( F .P .I.

This schem e fitte d the data v e ry w ell.

F e m a le C ro s s e d With M orphologically E x tre m e M ale

164965).

The p ro g en y se g re g a te d fifty -th re e m orp h o lo g ically

e x tre m e m a le s , fo rty -o n e fe m a le s, and no in te rs e x e s .

The m ale

w as (XY Aa Gg), as in d icated in the f i r s t c r o s s , and the fem ale
could be any one of th re e types:
(XX aa gg).

(XX AA GG), (XX Aa Gg), o r

By a ssu m in g linkage of the A-G o r a -g , only m a les

and fe m a le s would re s u lt.

The ra tio (53:41) has a c h i-s q u a re

value of 1.532 and a P value of 0.21 fo r a 1:1 ra tio .
III.

F e m a le C ro s se d With M orphologically E x trem e M ale

(F .P .I. 164965).

The r e s u lts fo r sex e x p re ssio n w ere th irty -o n e

81
m o rp h o lo g ic a lly e x tre m e m a le s and tw e n ty -six fe m a le s , plus
six s tro n g fem a le in te r s e x p la n ts .

The m ale was (XY Aa Gg),

and in th is c a s e the fem a le was p ro b ab ly (XX Aa gg).

This

could be p o s sib le b ecau se th is fem ale was fro m the p rogen y of
a se lfe d in te r s e x p la n t.

The expected r e s u lts of such a c ro s s

w ould be two m a le s to one fem ale to one fem ale in te r s e x of
two ty p e s.
A gain, en v iro n m en t could m odify the 1:1 ra tio of fem ale
to fe m a le in te r s e x type.

But, the fa c t th a t som e a n d ro e c io u sn e ss

w as p r e s e n t in the fe m a le s in th is c r o s s , and not in the p rev io u s
c r o s s , in d ic a te d a d ifferen c e in the genotype of the two fem ale
p la n ts involved.
IV.

F e m a le C ro s s e d w ith In te rs e x P la n t.

The in te r s e x

p la n t u se d w as a p u re -b re e d in g in te rs e x , the p ro g en y of which
gave one hundred ten in te r s e x and two fem ale in te r s e x p la n ts.
It was then of the genotype (XX AA gg).

This p lan t, when used

as the p o llen p a r e n t fo r a fem ale p lan t, gave a progeny of nine
in te rs e x , e ig h ty -fo u r fe m a le in te rs e x , and four fe m a le .

The

nine in te r s e x and fo u r fem a le p lan ts o b serv ed could have been
due to en v iro n m e n ta l influ ences or e r r o r s in sco rin g .

82
A ssu m in g a fe m a le w ith the genotype of (XX AA GG),
th e n th e re s u ltin g p ro g en y would be all (XX AA Gg), which is
a fe m a le in te r s e x genotype.
V.

F e m a le C ro s se d With In te rs e x P la n t.

The i n t e r ­

sex p la n t w as of the genotype (XY Aa GG), as ind icated by the
r a tio s of its p ro g e n y a s a r e s u lt of having been selfed (R efer
to P la n t No. 40).

The seg reg atio n fo r sex e x p re ssio n of th is

c r o s s w as one m a le , tw elve nonfunctional m ale in te rs e x , tw entynine m ale in te r s e x , one in te rs e x , one fem ale in te rs e x , and
f o r ty fe m a le s .

The m a jo r c la ss ific a tio n s a re fem a les and i n t e r ­

sex ty p es in the ra tio of 1:1.

If the genotype of the fem ale was

(XX A a GG), and th at of the in te r s e x was (XY Aa GG), the
re s u ltin g ex p ected p ro g en y would be fo u r fem ale to one in te rs e x
to two m ale in te r s e x to one m ale.

T his fits the data obtained.

The r a tio s of the in te rs e x types v a ry som ew hat, as was to be
expected, due to the clo se balancing of sex fa c to rs and th e ir
re a c tio n to en v iro n m en tal influences.

D iscus sion

It h as been shown fro m the data c o llected over fo u r
g e n e ra tio n s of c o n tro lle d b reed in g of spinach, th a t the in h e rita n c e

83
of sex is no t a sim p le p a tte rn , bu t is a com plex of s e v e ra l
f a c to r s lo c a te d on m o re than one p a ir of ch ro m o so m e s.
The a ssu m p tio n of an X-Y m ech an ism was n e c e s s a r y to
f it a 1:1 r a tio .

The n u m b er of fa c to rs m aking up the sexual

blo ck of the X-Y ch ro m o so m es is not known, but it a p p ea re d
to be m o re th an a single fa c to r.
The A-G gene linkage group and the YY type was b ased
upon the gen etic data of in te r s e x p lan ts seg reg atin g fo r m ales
and fe m a le s .

The o c c u rre n c e of a low c r o s s o v e r freq u en cy

w as u tiliz e d to explain the in te r s e x p la n ts.
F u r th e r study, using the m a te r ia l which now a p p e a rs to
be known gen otypically , should c la rify som e of the s till-o b s c u re
p a tte r n s of in te r s e x type seg reg atio n .
The v a rio u s re s p o n s e s of the d ifferen t genotypes to en ­
v iro n m e n ta l effects need f u rth e r study.

This is a v e ry co m ­

p le x p ro b le m , and, a s th e re a re two v a ria b le s , it would be a
c o n s id e ra b le ta s k to obtain conclusive r e s u lts .

SUMMARY

C ytological Study

S p in acia o le ra c e a L . has a chrom osom e num ber of twelve
(n = six ).
T h ere a r e d iffe re n c e s betw een lin e s concerning the n u m ­
b e r of n u c le o la r c h ro m o so m es, and in no line w as th e re e v i­
dence of a h e te ro m o rp h ic chrom osom e p a ir.

T h ere w ere no

c h ro m o so m a l d iffe re n c e s o b se rv e d betw een m ale and in te r s e x
lin e s .
T e tra p lo id spinach was p roduced and studied, and the
p ro d u ctio n of p o llen was o b serv ed to be ir r e g u la r .

G enetic Study

A schem e was su ggested to fit the o b serv ed sex in h e r i­
ta n ce.

It was p r im a r ily an X-Y sy stem , plu s two p a ir s of linked

m odifying gen es, independent of the X-Y sy stem , and having a
v e ry low c r o s s o v e r freq u en cy .

The existence of YY m a les and

YY in te r se x e s w as a ssu m e d , b a se d on g en etical data and cy to ­
lo g ic a l o b s e rv a tio n s .

85
C o lor F a c to r A, a sin g le-g en e type of in h e rita n c e , can
be u s e d a s a m a r k e r gene fo r c r o s s e s betw een in te r s e x p lan ts
w h ere e m a sc u la tio n is an inhibiting fa c to r.
E n v iro n m en t is a fa c to r which affects the e x p re s s io n of
c e r ta in c la s s e s of in te r sex es.
Sex e x p re s s io n affects the developm ent of flow er s ta lk s,
bu t the in itia tio n of flo w er stalk s is co n tro lled by a se p a ra te
f a c to r o r f a c to r s independent of sex e x p re ssio n .

BIBLIOGRAPHY

1.

A llen, C. E,
1940.
The Genotypic B asis of Sex E x p re s s io n
in A n g io sp e rm s. Bot. Rev. 6:229-300.

2.

A r a r a ta ja n , A. G.
1931. H etero ch ro m o so m e in the Wild
Spinach.
C. R. (dolclady) Acad. Sci. U.R.S.S. 24:
56-57.

3.

B o w se r, P . H. 1943. U npublished re p o rt of seed tr i a l s
in the U pper P en in su la of M ichigan. Dept, of
H o rt., M ich. State C ollege.

4.

B rid g e s ,
C. B. 1916. N on-disjunction as P ro o f of the
C hrom osom e T heory of H ered ity . G enetics 1:1-52.

5.___________ .
1925. Sex in R elation to C hrom osom es and
G enes. A m e r. Nat. 59:127-137.
6.

_________ .
1939. Sex and In te rn a l S e cretio n s.
2nd ed.
(Chap. 2, C ytological and G enetical B a sis of Sex),
pp. 15-63.

7.

D arlin g to n , C. D.
1951. G enetics in the 20th C entury
(Mendel and the D eterm in an ts), pp. 315-332.

8.

D o lch er, T.
1949. Sulla C ario logia di Spinacia tu rk e s ta n ic a
M. M. Ilijn .
C aryologia 2:55-59.

9.

E m e rso n , R. A.
1924. A G enetic View of Sex E x p re ssio n
in F lo w erin g P la n ts . Science 59:176-182.

10.

G illy, C. L ., and G. B. W ilson.
1952. Sex E x p re s s io n in
the A n g io sp erm s. M ich. State C oll., Dept, of Bot.
(unpublished data).

11.

G old sch m idt, R.
1934.
( a b s tr a c t) .

L y m a n tria .

Bibliog. Gen. 11:1

87
12.

H aga, T.
1935.
Sex and C hrom osom es in Spinacia o le ra c e a
L.. Ja p . J o u r. Gen. 10:218-222.

13.

__________ . 1938.
The Sex R atio in Spinach.
Oyohi Dobitu. 6:1573-1574.

14.

H ard h, H.
1939.
T utkim uksia K ro m o so m i-m o rfo lo g ia sta
ja P o ly s o m a tia -e le m io s ta Spinacia o le ra c e a 11a L.
M a a ta lo u st A ikakausk 11:317-332 (a b s tra c t).
B iol.
A bst. 14:12887.

15.

H ay asi, S.
1932. R elatio n Betw een Age of the Seed and
Sex in Spinach. A g ric. and H o rt. Japan . 7:11491156.

16.

H ira ta , K ., and K. Y am am oto.
1931. On the O ccu rre n c e
of F e m a le In te r sexual P la n ts in Spinacia and M eland r iu m . Jap . J o u r. Gen. 7:105-107 (su m m ary).

17.

Jo n e s, D. F .
1934. U nisexual M aize P la n ts and th e ir
B earin g on Sex D eterm in atio n in o th e r P la n ts and
in A n im als.
G enetics 19:552-567.

18.

K o taro , K.
1935. C ytological Studies on the C ultivated
C ro c u s.
Jap . J o u r. Gen. 11:162-168.

19.

Loehw ing, W. F .
1938. P h y sio lo g ical A sp ects of Sex in
A n g io sp e rm s.
Bot. Rev. 4:581-625.

20.

Love, D o ris.
1942. In te r sex u ality in M elandrium rub rum
P ro b a b ly C aused by a T ra n slo c a tio n Betw een the
Sex C h ro m o so m es (an a b s tra c t).
H e re d ita s 28:
497-498.

21.

L o rz , A.
1937.
C ytological Investig atio n s on F ive Chenopo d iaceo u s G en era w ith Special E m phasis on C h ro ­
m oso m e M orphology and Som atic Doubling in
S p in a c ia . C ytologia 8(2):241-276.

22.

M a g ru d e r, R ., et al.
1938.
D escrip tio n of Types of P r i n ­
cip al A m e ric a n V a rie tie s of Spinach. M isc. P ubl.
No. 316, USDA.

Syokubutu

88
23.

M cClung, E. E.
1902.
The A c c e s s o ry C h ro m o so m e-S ex D e te rm in a n t?
B iol. B ull. 3:43-84 (a b s tra c t).

24.

M iry u ta , J . P .
1937.
Sex in P la n ts .
843-850.

25.

N egodi, G.
1934.
C om portam ento E r e d ita r io del Monoc e ism o in S pinacia o le ra c e a . Riv. Biol. 17:445-450.

26.

N o h ara, S.
1923. G enetical Studies on Spinacia.
J o u r. B ot. 1:111-120.

27.

Ono, T.

28.

P o o le , C. F ., and P . C. G rim b a ll.
1939. In h eritan ce of
New Sex F o rm s in Cucum is m elo L. Jo u r. H ered.
30:21-25.

29.

R osa, J . T.
1925.
Sex E x p re s s io n in Spinach.
l(12):259-274.

30.

_________ .
1928.
The In h eritan ce of F lo w er Types in Cu­
cu m is and C itru llu s .
H ilg ard ia 3(9):233-250.

31.

S chaffner, J . H.
1935. O b se rv a tio n s and E x p erim en ts on
Sex in P la n ts .
Bui. T o rre y Bot. Club 62:387-402.

32.

Sinoto, Y.
1929. C hrom osom e Studies in som e D ioecious
P la n ts , w ith S pecial R eferen ce to the A llo so m es.
C ytologia 1:109-191.

33.

Sugim oto, Y.
1948. Studies on the B reeding of Spinach.
2. Sex E x p re s s io n and G enetical E xplanation.
H ort.
A sso c. Jap an . J . 17:17-83.

34.

Tandon, S. L.
1951.
C olchicine Induced P olyploidy in
Spinach.
C ur. Sci. 19:66.

A C ontribution to the G enetics of
B ull. Acad. Sci. U.R.S.S. Sci. B iol.

Jap .

1935.
C hrom osom en und S exualitat von Rumex
a c e to s a . D ei. Rep. Tohoku. Univ. Biol. 10:41
( a b s tr a c t) .

H ilg a rd ia

89
35.

36.

T asch n jak o w a, M.
1929.
U ntersuchungen u b e r die K ern b e sc h a ffe n h e it e in ig e r D io z isc h e r P flan zen .
Z e itsc h r,
W iss. B iol. Abt. E . P la n ta 7(4):427-443.
W arm ke, H. E.
1946.
in M elan d riu m .

Sex D eterm in atio n and Sex B alance
A m er. Jo u r. Bot. 33:648-660.

37.

W arm ke, H. E ., and A. F . B la k eslee.
1939.
E ffect of
P o ly p lo id upon the Sex M echanism in D ioecious
P la n ts .
G enetics 24:88-89 (an a b s tra c t).

38.

_________ . 1940. E s ta b lis h m e n t of a 4n D ioecious Race in
M elan drium . A m e r. J o u r. Bot. 27:751-762.

39.

W hitaker, T. W.
1931. Sex R atio and Sex E x p re s s io n in
the C u ltiv ated C u cu rb its. A m er. Jo u r. Bot. 18:
359-366.

40.

W hiting, P . W.
W asps.

1935. Sex D eterm in atio n in B ees and
J o u r. H ered . 26:263.

41.

W ilson, G. B.
1946.
C ytological Studies in the M usae.
I. M eiosis in som e T rip lo id C lones. G enetics 31:
214-258.

42.

_________ . 1946. C ytological Studies in the M usae.
III.
M eio sis in som e Seedling C lones. G enetics 31:
483-493.

43.

44.

45.

.
1950. N u clear Cytology.
lege P r e s s .

M ichigan State C o l­

Winge, O.
1924. On Sex C h ro m o so m es, Sex D eterm in atio n
and P re p o n d e ra n c e of F e m a le s in Some D ioecious
P la n ts .
C. R. T rav . L a b o r. C a rls b e rg 15(5): 1-26.
1931. X and Y L inked In h eritan ce in M elan d riu m .
H e re d ita s 15:127-165.

90
46.

1934.
The E x p e rim e n ta l A lte ra tio n of Sex
C h ro m o so m e s into A utosom es and Vice V e rsa ,
as I llu s tr a te d by L e b is te s . C. R. T rav . L abo r.
C a rls b e rg 21:1.

47.

1937. G o ld sch m id t's T heory of Sex D e te rm in a ­
tion in L y m a n tria . Jo u r. Gen. 36:81.

48.

Y am polsky, C.
1933.
Sex and C h rom o so m es in P la n ts.
T o r r e y Bot. Club Bui. 60:639-655.

APPENDIX

OTHER GENETIC CHARACTERS OBSERVED
IN S. OLERACEA L.

B e s id e s sex e x p re s s io n , o th e r c h a r a c te r s which a r e
g e n e tic a l in n a tu re w ere o b se rv e d during the c o u rse of the in ­
v e stig a tio n .

C olor F a c to r A

T his is a sin g le -g en e f a c to r, fo r re d co lo r a t the s te m ro o t a r e a .

The a r e a w hich w ill show the co lo r v a rie s fro m

o n e -h a lf in ch to th re e in ch es, depending upon the size of the
p la n t, and a tta in s m axim um in te n sity when the p lan ts a re in full
flo w e r.

Red is dom inant o v er c o lo rle s s , w ith m o st c o m m e rc ia l

v a r ie tie s being h etero zy g o u s fo r the fa c to r.
th r e e g e n e ra tio n s

D ata fro m the la s t

shown in ta b le s in the Appendix ind icate the

n a tu re of the in h e rita n c e of this gene.

This c h a r a c te r could

be u sed a s a m a rk e r gene in the c ro s s in g of in te r s e x p lan ts
w h ere e m a sc u la tio n is im p o ssib le in p r a c tic e .

By the use of

a hom ozygous r e c e s s iv e in te r s e x p lant, a c r o s s can be m ade
w ith a hom ozygous dom inant p o llen p a re n t plan t, and when the
p ro g en y is grow n, a ll re d —
stem. (C olor F a c to r A) p lan ts w ill

93
be c r o s s e d ind ivid u als, and all w h ite -s te m p la n ts will be the
r e s u l t s of se lfe d seed.

C olor F a c t o r B

This f a c t o r was noted on the m orp h o lo g ically e x tre m e
m a le p la n t u s e d in c r o s s in g .

It is ap p aren tly a single-gene

type in h e rita n c e , but th is has not been conclusively shown.

In

th is c a s e , the r e d color p e r s i s t s v e ry pale throughout the flow er
s talk , and if a n th e r s a r e fo rm e d the a n th e r wall b eco m es quite
re d .

This f a c to r , if p r e s e n t, will m a sk Color F a c to r A.

H om ed-seed F acto r

All of the p la n ts b e a rin g seed which w ere c r o s s e d with
th is m o rp h o lo g ica lly e x tre m e m ale e x p r e s s e d the h o r n e d - s e e d
condition.

This is in a g r e e m e n t with N ohara (1923), who showed

th a t this h o r n e d - s e e d f a c to r had a single-gene type of in h eritan ce,
and the h o rn ed seed was dominant o v er the round seed.

F rom

o b s e rv a tio n s of h o rn ed seed, it was noted that the seed had
f r o m two to fo u r sp in es, o r h o rn s, and that in some rounds e e d e d ty p e s, s m a ll h o rn s w ere o b s e rv e d on seed fr o m some
p la n ts .

94
The M orph o log ically E x tre m e Type Male P la n t

All m a le s f r o m the c r o s s with this type m ale p la n t w ere
of the sam e type, being m orp h olo gically e x tre m e .

This also a p ­

p e a r s to be a dom inant condition, and is fully e x p r e s s e d only
by m a le p la n ts .

Savoyed Type Leaf and Dwarf Type
F lo w e r Stalk

Savoyed type le a f and dwarf type flow er stalk conditions
have been o b se rv e d , but th e ir mode of in h e ritan ce is not known.

F a s c ia tio n and P r o lif e r a tio n of
Growing P o in ts

One in b re d line was o b serv ed fo r this c h a r a c te r .

The

flo w er stalk s all b eca m e fa s c ia te d , and, as the plant reach e d
full m a tu r ity , the tips of the f a s c ia te d p o rtio n s of the ste m
b eca m e a m a s s of growing points.

Its mode of in h eritan ce is

unknown, but it a p p e a rs to be a r e c e s s iv e c h a r a c te r .

R esponse to P hoto perio d

Spinach r e m a in s in the vegetative state until a c e r ta in
len gth of p h o to p erio d e x is ts .

The length of photoperiod r e q u ir e d

95
to s tim u la te flo w e r stalk developm ent v a r ie s with, d ifferen t
p la n ts .

Some of the fo re ig n p la n t introductions of S. ole r a c e a

w e re o b s e r v e d to resp o n d to a photoperiod of nine h o u rs, while
m o s t c o m m e r c ia l v a r i e t i e s r e q u ir e a photoperiod of f ro m twelve
to f o u r te e n h o u r s to in itiate f lo w e r - s ta lk development.

The sex

of the p la n t m odifies the r a te of f lo w e r - s ta lk development, but
a p p a r e n tly has little influence on f lo r a l initiation.

It was o b ­

s e r v e d th a t in t e r s e x and fem ale plan ts will re m a in vegetative
lo n g e r than m a le , if the populations o b serv ed w ere of the sam e
genotype f o r p h otoperiodic r e s p o n s e .

However, it was also

o b s e r v e d th a t f e m a le s and in t e r s e x p lan ts will f o r m flow er
s ta lk s ah ead of m ale p la n ts.
The explanation fo r this is the in h e re n t r e s p o n s e to
p h o to p e rio d within the v a rio u s p la n ts.

A nother indication of

th is is th a t the in t e r sex p la n ts which w ere used in this e x p e r i­
m e n t w e re u su a lly se le c te d e a rly , and as a r e s u l t w ere uncon­
s c io u s ly s e le c te d f o r re s p o n s e to s h o r te r photoperiods, as in d i­
c a te d by the e a r l y f lo w e r - s ta lk fo rm a tio n in the p ro g en ie s grown
in the e a r l y spring.

SEX REVERSAL

D e s c rip tio n of P a r e n t P la n t of P ro g en y
(XF -14-1 2 -8-38 )

A r e d - s t e m m e d fem a le plan t grown in the g reenhouse in
the w in te r of 1951-52 p ro d u ced a v e ry few a n th e rs (about ten
to fifteen) n e a r the lo w er p o rtio n of the main flow er stalk,
while the r e m a in d e r of the p la n t was fe m a le .

The m ain flow er

s talk r e a c h e d a height of 3 feet, and was all fe m a le , when an
apparent " s e x r e v e r s a l"
the m a in flo w er stalk.

took place within the l a s t 5 inches of
Within th is 5 -in ch span, the flo w ers

tr a n s f o r m e d f r o m the p u re fem ale condition through a s e r i e s
of the m onoecious com plex and h e rm a p h ro d itic flo w ers to a
p u r e m a le condition, which te rm in a te d the flow er stalk.

S im ­

i l a r conditions e x iste d to a l e s s e r extent on the l a t e r a l s .
The only s e e d which was s e t on this plan t developed
n e a r the b a s e of the m ain flow er stalk, where the f i r s t a n th e rs
a p p e a re d , and a l a r g e r n u m b er of seeds was s e t f r o m the t e r ­
m in a ls of the flo w er stalk s where the l a t e r a n th e rs ap p eared .
The m a jo r p o rtio n of the flo w er stalk, which was p u re fem a le,
fa ile d to s e t seed, p ro b ab ly due to the lack of pollen.

97
While th is was a m a n ifestatio n of environm ent, it was
not u n iv e r s a l f o r all the fem ale p la n ts grown under this con­
dition, b u t only a p p e a re d on a few p la n ts.

This indicates,

again, th a t it is a com bination of in te rn a l f a c to r s (genetic c o n ­
trol) and e x te r n a l f a c to r s which d e te rm in e th is
in spinach.

"sex re v e rsa l"

PEDIGREE EXAMPLES

P la n tin g N um ber One, Spring, 1952
(XF- 14- 11-15-1)

In the sp rin g of 1950, an in t e r s e x p lan t was selec ted
f r o m a f ie ld p lanting of Long Standing B loom sdale and Nobel.
The p la n t s e le c te d was of the Long Standing B loom sdale v arie ty ,
w ith no c o n tro l o v er the m ale p a re n t; however, this p la n t was
an i n t e r s e x which was ten p e r cen t fem ale and ninety p e r cent
m a le .

This p la n t w as desig n ated as (XF).

The seed f r o m this

p la n t was p la n ted in the green h o u se in the w inter of 1950-51.
F r o m the p ro g en y of this planting an in te r s e x was selfed.
p la n t was d esig n ated as (XF-14).

This

The seed f r o m th is plant was

p la n te d in the fie ld in the spring of 1951.

A w h ite -s te m m e d

i n t e r s e x p la n t was selfed f r o m the progeny and was designated
a s ( X F - 1 4 - 11).

The seed f r o m this p lant was planted in the

g reen h o u se in the w in te r of 1951-52.

F r o m the progeny of

th is planting, a white - ste m m e d i n t e r s e x plant was selfed.
p la n t was d e sig n a te d ( X F - 14-11 - 15).

This

The seed f r o m this p la n t

was p la n te d in the field in the spring of 1952, and the pro g eny

99
f r o m th is p lan tin g was d esig n ated ( X F - 14-11 -15-1).
g r e e would then be li s t e d as follows:

The p e d i­

(XF); (XF-14); (XF-14-11);

( X F - 14-11-15); (X F -1 4 -1 1 -1 5 -1 ).

P lan tin g N u m b er F o r ty - s e v e n , Spring, 1952
[ ( X F - 3-2) x ( X F -3 -2 )-1 -47]

(XF); ( X F - 3); (X F-3-2) x (X F-3-2); [(XF-3-2) x (X F - 3 - 2 ) - l] ;
[(X F -3-2) x (X F-3-2) -1-47].
F o r d e s c rip tio n s of the individuals, consult Tables VIII,
IX, X, and XI in the Appendix, and fo r d es c rip tio n s of the
p r o g e n ie s of individuals, co n su lt Tables XII, XIII, XIV, and XV
in the Appendix.

100
T A B L E VIII
PLANTING PLAN, WINTER, 1950-51
(all s e e d - b e a r in g p lan ts w ere of the Long Standing
B lo o m sd ale v a rie ty ; m ale p a r e n t was unknown)

1.

(XF) fem a le

9.

2.

(XF) fem a le

10.

(XF) in te r sex

3.

(XF) fem a le

11.

(XF) in te r sex

4.

(XF) fe m a le

12.

(XF) in te r sex

5.

(XF) fem a le in te r sex

13.

(XF) m ale in te r sex

6.

(XF) fe m a le in te r sex

14.

(XF) m ale in te r s ex

7.

(XF) fem a le in te r sex

15.

(XF) fem ale

8.

(XF) fem a le in te r sex

(XF) fem ale

101
TABLE IX
PLANTING PLAN, SPRING, 1951

1.

(XF-3)

in t e r sex

7.

(XF-11) in te r s e x

2.

(XF-3)

in t e r sex

8.

(XF-12) in te r s e x

3.

(X F -6)

in tersex

9.

(XF-14) in te r sex

4.

(XF-7)

in t e r s e x

10.

(XF-14) in te r sex

5.

(XF-9)

in tersex

11.

(XF-14) in te r sex

6.

(XF-11) i n t e r s e x

12.

(XF-14) in te r s e x

102
TABLE X
PLANTING PLAN, WINTER, 1951-52
P e d i g r e e No.

Sex

Stem Color

m ale x fem ale

r e d x white

1.

(X F -3 -2 )x (X F -3-2)

6.

( X F - 14-9)

in t e r s e x

re d

7.

(X F -1 4 - 11)

in t e r s e x

red

8.

(XF -1 4 - 12)

in t e r s e x

red

12.

(XF -14-9)

in t e r s e x

15.

(XF -14-11)

in te r sex

white

103
TABLE XI
PLANTING PLAN, SPRING, 1952a

P e d ig r e e No.

Sex

Stem
Color

(XF - 14 -11-15)

in tersex

white

2.

(X F-14 - 11-15)

in tersex

white

3.

(XF - 14-11-15)

in t e r s e x

white

4.

(X F -1 4 - 11-15)

i n te r s e x

white

5.

(X F- 14- 11-15)

in tersex

red

6.

(XF -14-11-15)

in te r sex

white

7.

(X F -1 4 - 11-15)

in te r sex

white

8.

( X F - 1 4 - 11- 15)

in te r sex

white

9.

(XF -14-11-15)

in te r sex

white

i—
i

(XF -14 -11 - 15)

in tersex

white

20.

(X F -1 4 - 11 -7)

in t e r s e x

re d

21.

(XF -1 4 -11 -7 )

in t e r s e x

re d

22.

(XF -1 4 - 11-7)

in te r sex

white

23.

(X F -1 4 - 11-7)

in t e r s e x

red

24.

(XF -14 - 11-7)

in t e r s e x

red

25.

( X F - 14-11-7)

in te r sex

red

26.

(XF -14 -1 1 -7 )

in t e r s e x

red

00

1.

104
T A B L E XI (C o n tin u e d )

P e d ig r e e No.

Sex

Stem
Color

27.

(XF - 1 4 - 9 - 1 2 )

in tersex

white

28.

( X F - 14-9 -12)

in te r s e x

re d

29.

( X F - 14-9-6)

in tersex

red

30.

(X F - 1 4 - 9- 6 )

in te r sex

red

31.

(X F - 1 4 - 9 - 6 )

in te r s e x

red

32.

(XF-14-9-6)

in te r s e x

re d

33.

( X F - 1 4- 9- 6 )

in te r sex

red

36.

( X F - 1 4 - 1 2 - 8)

in te r sex

red

37.

(XF - 1 4 - 12 - 8)

in tersex

re d

38.

( X F - 1 4 - 12-8)

in te r sex

re d

40.

[ ( X F - 3 - 2 ) x ( X F - 3 - 2 ) -1]

in te r sex

re d

41.

[ ( X F - 3 - 2 ) x ( X F - 3 - 2 ) -1]

in t e r s e x

red

42.

[(X F-3-2)x(X F-3-2)-l]

in te r s e x

red

43.

[(XF - 3 - 2 ) x ( X F - 3 - 2 ) -1]

in te r s e x

white

44.

[(XF - 3 - 2 ) x ( X F - 3 - 2 ) -1]

in te r sex

red

45.

[ ( X F - 3 - 2 ) x ( X F - 3-2) -1]

in te r sex

white

105
T A B L E XI (C o n tin u ed )

P e d ig r e e No.

Sex

Stem
Color

46.

[(XF - 3 -2 )x (X F -3-2) -1]

in te r sex

white

47.

[(X F -3 -2 )x (X F -3-2) -1]

in te r sex

red

48.

[(XF -3-2)x(X F - 3-2) -1]

in te r s e x

red

49.

[(X F -3-2)x(X F - 3-2) -1]

in t e r s e x

red

50.

[(X F -3 -2 )x (X F -3 -2 ) -1]

in te r sex

white

(XF -1 4 - 11-15)

in t e r s e x

white

11.

X

X

X

(F .P .I.)

m ale

red

(XF -14- 11-7)

fem ale

X

X

(X F -1 4 - 11-15)

in te r sex

re d
x
white

(XF - 14- 12- 8 )

fem ale

re d

X

X

X

(F .P .I.)

m ale

re d

(X F-14 - 12-8)

fem ale

white

X

X

X

(F .P .I.)

m ale

red

[XF - 14-12-8]

fem ale

red

X

X

X

[(X F -3 -2 )x (X F -3 -2 ) -1]

in t e r s e x

red

52.

(X F -1 4 - 1 l)b

in te r sex

red

53.

(XF -1 4 -9 )°

in te r sex

re d

19.

34.

35.

39.

106
T A B L E XI (C o n tin u e d )

P e d ig r e e No.

Stem
Color

Sex

J
54.

( X F - 1 4 - 11)

white

in te r sex

B ecau se of the env iro n m en tal effects under g r e e n ­
house conditions, the in t e r s e x p lan ts w ere all c o n sid ere d as
in t e r s e x , and no a tte m p t was made to f u r th e r c la s s ify them .
The c o lo r r e f e r s to the s te m colo r.
1^
Identical to n u m b e r 7 in w inter, 1951-52.
c

Id entical to n u m b er 6 in w in ter, 1951-52.
Id en tical to n u m b e r 15 in w inter,

1951-52.

107
T A B L E XII
DATA FROM WINTER, 1950-51, PLANTING
P e d ig r e e
No.

Male

I n te r s e x

F e m a le

Total

(XF - 1)

17

-

9

26

(XF-Z)

13

-

12

25

(XF-3)

17

2

12

28

(XF-4)

14

-

9

23

(XF-5)

9

-

14

23

(X F -6 )

13

1

13

27

(XF -7)

10

1

12

23

(XF - 8 )

6

-

16

22

(XF-9)

10

2

8

20

(XF- 10)

9

1

14

24

(XF-11)

12

2

12

26

(XF -13)

7

-

13

20

(XF-14)

6

4

4

14

(XF-15)

12

2

9

23

161

16

169

346

Total

108
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109
TABLE XIV
DATA FROM WINTER, 1951-52, PLANTING*

P e d ig r e e
No.

Male

In te rsex

Fe­
m ale

Stem Color
Total
Red

White

( X F - 14-9-6)

-

8

72

80

71

9

(X F- 14-9-12)

-

4

18

22

20

2

(XF- 14-11-7)

-

11

98

109

85

24

(X F- 14-11-15)

-

6

63

69

3

66

( X F - 14-12-8)

-

-

31

31

24

7

6

19

19

44

23

(X F -3-2)
X

21

(X F-3-2)

* The data on sex e x p re s s io n is not valid, as some of
the p la n ts s c o r e d as fem a le l a t e r tu rn e d out to be in te r s e x
p la n ts , producing a good s e t of seed.

110
T A B L E XV
DATA FRO M THE SPRING,

P e d ig re e
No.

M ale

1952, P LA N T IN G
N o n fu n c­
tio n a l
M ale
In te r sex

M ale
In te r sex

(XF - 1 4 - 1 1 - 1 5 - 1 )

-

-

1

(XF - 14 -1 1 -1 5 -2 )

-

-

10

(XF - 1 4 - 1 1 - 1 5 - 3 )

-

1

6

(XF - 1 4 -1 1 -1 5 -4 )

-

1

1

(XF - 1 4 - 1 1 - 1 5 - 5 )

-

-

20

(XF - 1 4 -1 1 -1 5 -6 )

-

-

-

(XF - 1 4 - 1 1 - 1 5 - 7 )

-

(XF - 1 4 - 1 1 - 1 5 - 8 )

-

-

3

(XF - 1 4 -1 1 -1 5 -9 )

-

1

19

(XF - 1 4 - 1 1 - 1 5 - 1 8 )

-

14

(XF - 1 4 -1 1 -7 -2 0 )

-

13

3

(XF - 1 4 -1 1 -7 -2 1 )

-

12

47

(XF - 14 -1 1 - 7 - 2 2 )

-

-

26

( X F - 1 4 - 1 1-7-23)

-

8

44

(XF - 14 -11 - 7-24)

1

6

72

Ill

T A B L E XV (C o n tin u e d )

I n te r s e x

F e m a le
I n te r s e x

Stem Color
F e m a le

Total
Red

White

45

3

-

49

-

49

68

-

-

78

-

78

33

1

-

41

1

40

55

1

-

58

1

57

56

2

78

60

18

110

2

-

112

-

112

73

4

-

80

3

77

53

5

-

61

-

61

36

1

57

57

36

-

50

50

42

-

55

55

6

-

65

65

-

32

110

1

109

52

-

16

-

-

68

54

14

12

-

-

91

72

19

112
T A B L E X V ( C o n t in u e d )

P e d ig re e
No.

M ale

Nonfunc tio n a l
M ale
In te r sex

M ale
In te rse x

(XF - 1 4 - 1 1 - 7 - 2 5 )

-

-

43

(XF - 1 4 -1 1 -7 -2 6 )

-

7

84

(XF - 1 4 -9 - 12-27)

-

-

13

(XF - 1 4 - 9 - 1 2 - 2 8 )

-

1

31

3

58

( X F - 1 4 -9 -6 -2 9 )
(XF - 1 4 -9 -6 -3 0 )

-

-

72

(XF - 1 4 -9 -6 -3 1 )

-

4

34

(XF - 1 4 -9 -6 -3 2 )

-

1

71

(XF - 1 4 -9 -6 -3 3 )

-

-

14

1

-

(XF - 1 4 - 1 2 - 8 - 36)
( X F - 1 4 - 12-8-37)

-

1

6

(XF - 1 4 -1 2 -8 -3 8 )

6

35

41

[ ( X F - 3 - 2 ) x ( X F -3 -2 ) - 1 -40]

47

-

6

[ ( X F - 3 - 2 ) x ( X F - 3 - 2 ) -1 -4 1 ]

28

39

7

113
T A B L E XV (C o n tin u e d )

I n te r s e x

40

F em ale
In te rse x

-

Stem Color
F e m a le

-

El

Total
Red

White

83

61

22

112

84

28

36

1

-

50

-

50

13

-

-

45

32

13

13

-

-

74

56

18

E3

-

-

95

77

18

23

4

1

66

49

17

3

-

-

75

75

-

55

12

-

81

61

20

8

15

21

45

31

14

17

24

13

61

46

15

-

-

82

61

21

3

-

20

76

54

22

-

1

21

96

74

21

114
T A B L E X V ( C o n ti n u e d )

P e d ig re e
No.

M ale

Nonfunc tio n a l
M ale
In te r sex

M ale
In te r sex

-

[(XF -3 -2 ) x ( X F - 3 - 2 ) - 1 - 4 2]

83

8

[(XF -3 -2 ) x ( X F - 3 - 2 ) - 1 - 4 3]

41

19

14

[(XF - 3 - 2) x(XF - 3- 2) -1 -44]

15

16

20

[(XF - 3 -2 )x (X F -3 -2 ) - 1 -45]

10

38

14

[(XF - 3 -2 )x (X F -3 -2 ) - 1 -46]

17

22

28

[(X F -3 -2 )x (X F -3 -2 )-1 -4 7 ]

-

9

23

[ (X F - 3 -2 )x ( X F - 3 - 2 ) - 1 - 4 8 ]

9

16

31

[(X F -3 -2 )x (X F -3 -2 )-l-4 9 ]

3

11

21

[(XF - 3 - 2 )x (X F -3 -2 ) - 1-50]

35

27

(X F -14-1 1 -1 5 -1 1 ) x F .P .I .
i n t e r s e x x e x t r e m e m a le

39*

-

-

( X F - 14- 1 2-8-34) x F . P . I .
f e m a le x e x t r e m e m a le

53*

-

-

(X F -14-12-8-35 ) x F .P .I.
f e m a l e x e x t r e m e m a le

31 *

3

-

[ X F - 1 4 - 1 2 - 8 - 3 9 ] f e m a le
X

[(X F -3-2)x(X F -3 -2 )-1 -4 0 ]

1

12

29

115
T A B L E XV (C o n tin u e d )

I n te r s e x

F e m a le
In te r sex

Stem Color
F e m a le

Total
Red

White

-

-

24

115

86

29

4

2

21

1 01

4

97

-

2

18

71

54

17

7

-

21

90

3

87

4

1

24

96

-

96

19

1

19

71

52

19

1

-

25

82

58

24

7

2

19

63

49

14

-

-

19

84

1

83

23

16

78

78

-

-

41

94

94

-

6

26

63

63

1

1

41

85

85

-

116
T A B L E XV (C o n tin u ed )

P e d ig re e
No.

M ale

N o n fu n c­
tio n a l
M ale
In te rse x

M ale
In te r sex

(XF - 14 -1 1 - 7 - 1 9 ) f e m a le
-

-

X

(XF - 1 4 -1 1 -1 5 -6 )

(XF -1 4 - 1 1 - 7 )

-

1

8

( X F - 1 4 -9 -6 )

-

-

11

(X F - 14- 11-15)

-

-

* D en o tes e x t r e m e

m a le .

3

117
T A B L E XV (C o n tin u e d )

I n te r s ex

F em ale
In te r s e x

Stem Color
F e m a le

Total
Red

White

9

84

4

97

47

50

36

16

10

71

45

16

12

6

3

32

24

8

8

-

-

11

-

11

118
T A B L E XVI
DATA FROM SPRING, 1950, TESTING SPACING AND DATE
OF PLANTING ON THE SEX EXPRESSION OF SPINACH
P la n tin g

Date

Male

In te r sex

F e m a le

Total

Long Standing Bloom sdale
1

4 /22

46

10

35

91

2

4 /29

141

33

137

311

3

5/6

152

27

148

327

4

5/13

142

24

146

312

5

5/20

117

11

93

221

598

105

559

1,262

Spacing
T otal
(1"

-

2^)

298

50

287

635

(4 "

-

6 ’»)

190

36

178

404

(8 "

- 10” )

110

19

94

223

119
T A B L E XVI (C o n tin u e d )
P la n tin g

Date

Male

In te r sex

F e m a le

Total

Nobel
1

4 /2 2

20

1

17

38

2

4/29

56

3

52

111

3

5/6

91

4

85

180

4

5/13

89

3

10 1

193

5

5/20

54

1

71

126

310

12

326

648

Spacing
T otal

129

5

143

277

(4 "

6 ")

98

2

114

214

83

6

69

157

1

o
i—
l

2”)

00

(1M -